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The Atomic Bomb: Arguments in Support Of The Decision

Note: This section is intended as an objective overview of the decision to use the atomic bomb for new students of the issue. For the other side of the issue, go here.

Argument #1: The Atomic Bomb Saved American Lives

The main argument in support of the decision to use the atomic bomb is that it saved American lives which would otherwise have been lost in two D-Day-style land invasions of the main islands of the Japanese homeland. The first, against the Southern island of Kyushu, had been scheduled for November 1 (Operation Torch). The second, against the main island of Honshu would take place in the spring of 1946 (Operation Coronet). The two operations combined were codenamed Operation Downfall. There is no doubt that a land invasion would have incurred extremely high casualties, for a variety of reasons. For one, Field Marshall Hisaichi Terauchi had ordered that all 100,000 Allied prisoners of war be executed if the Americans invaded. Second, it was apparent to the Japanese as much as to the Americans that there were few good landing sites, and that Japanese forces would be concentrated there. Third, there was real concern in Washington that the Japanese had made a determination to fight literally to the death. The Japanese saw suicide as an honorable alternative to surrender. The term they used was gyokusai, or, “shattering of the jewel.” It was the same rationale for their use of the so-called banzai charges employed early in the war. In his 1944 “emergency declaration,” Prime Minister Hideki Tojo had called for “100 million gyokusai,” and that the entire Japanese population be prepared to die.

For American military commanders, determining the strength of Japanese forces and anticipating the level of civilian resistance were the keys to preparing casualty projections.  Numerous studies were conducted, with widely varying results. Some of the studies estimated American casualties for just the first 30 days of Operation Torch. Such a study done by General MacArthur’s staff in June estimated 23,000 US casualties.

U.S. Army Chief of Staff George Marshall thought the Americans would suffer 31,000 casualties in the first 30 days, while Admiral Ernest King, Chief of Naval Operations, put them between 31,000 and 41,000. Pacific Fleet Commander Admiral Chester Nimitz, whose staff conducted their own study, estimated 49,000 U.S casualties in the first 30 days, including 5,000 at sea from Kamikaze attacks.

Studies estimating total U.S. casualties were equally varied and no less grim.  One by the Joint Chiefs of Staff in April 1945 resulted in an estimate of 1,200,000 casualties, with 267,000 fatalities. Admiral Leahy, Chief of Staff to the Commander in Chief, estimated 268,000 casualties (35%).  Former President Herbert Hoover sent a memorandum to President Truman and Secretary of War Stimson, with “conservative” estimates of 500,000 to 1,000,000 fatalities. A study done for Secretary of War Henry Stimson’s staff by William Shockley estimated the costs at 1.7 to 4 million American casualties, including 400,000-800,000 fatalities.

General Douglas MacArthur had been chosen to command US invasion forces for Operation Downfall, and his staff conducted their own study.  In June their prediction was American casualties of 105,000 after 120 days of combat.  Mid-July intelligence estimates placed the number of Japanese soldiers in the main islands at under 2,000,000, but that number increased sharply in the weeks that followed as more units were repatriated from Asia for the final homeland defense.   By late July, MacArthur’s Chief of Intelligence, General Charles Willoughby, revised the estimate and predicted American casualties on Kyushu alone (Operation Torch) would be 500,000, or ten times what they had been on Okinawa.

All of the military planners based their casualty estimates on the ongoing conduct of the war and the evolving tactics employed by the Japanese.   In the first major land combat at Guadalcanal, the Japanese had employed night-time banzai charges—direct frontal assaults against entrenched machine gun positions.  This tactic had worked well against enemy forces in their Asian campaigns, but against the Marines, the Japanese lost about 2,500 troops and killed only 80 Marines.

At Tarawa in May 1943, The Japanese modified their tactics and put up a fierce resistance to the Marine amphibious landings.  Once the battered Marines made it ashore, the 4,500 well-supplied and well-prepared Japanese defenders fought almost to the last man.  Only 17 Japanese soldiers were alive at the end of the battle.

On Saipan in July 1944, the Japanese again put up fanatical resistance, even though a decisive U.S. Navy victory over the Japanese fleet had ended any hope of their resupply.  U.S. forces had to burnthen out of holes, caves, and bunkers with flamethrowers. Japanese forces staged multiple banzai attacks. At the end of the battle the Japanese staged a final banzai that included wounded men, some of them on crutches.  Marines were forced to mow them down.  Meanwhile, on the north end of the island a thousand civilians threw committed suicide by jumping from the cliff to the rocks below after being promised an honorable afterlife by Emperor Hirohito, and after being threatened with death by the Japanese army. In the fall of 1944, Marines landed on the small island of Peleliu, just east of the Philippines, for what was supposed to be a four-day mission. The battle lasted two months. At Peleliu, the Japanese unveiled a new defense strategy. Colonel Kunio Nakagawa, the Japanese commander, constructed a system of heavily fortified bunkers, caves, and underground positions, and waited for the Marines to attack them, and they replaced the fruitless banzai attacks with coordinated counterattacks. Much of the island was solid volcanic rock, making the digging of foxholes with the standard-issue entrenching tool impossible. When the Marines sought cover and concealment, the terrain’s jagged, sharp edges cut up their uniforms, bodies, and equipment. The plan was to make Peleliu a bloody war of attrition, and it worked well. The fight for Umurbrogol Mountain is considered by many to be the most difficult fight that the U.S. military encountered in the entire Second World War. At Peleliu, U.S. forces suffered 50% casualties, including 1,794 killed. Japanese losses were 10,695 killed and only 202 captured. After securing the Philippines and delivering yet another shattering blow to the Japanese navy, the Americans landed next on Iwo Jima in February 1945, where the main mission was to secure three Japanese airfields. U.S. Marines again faced an enemy well entrenched in a vast network of bunkers, hidden artillery, and miles of underground tunnels. American casualties on Iwo Jima were 6,822 killed or missing and 19,217 wounded. Japanese casualties were about 18,000 killed or missing, and only 216 captured.  Meanwhile, another method of Japanese resistance was emerging.  With the Japanese navy neutralized, the Japanese resorted to suicide missions designed to turn piloted aircraft into guided bombs. A kamikaze air attack on ships anchored at sea on February 21 sunk an escort carrier and did severe damage to the fleet carrier Saratoga. It was a harbinger of things to come.

After Iwo Jima, only the island of Okinawa stood between U.S. forces and Japan. Once secured, Okinawa would be used as a staging area for Operation Torch. Situated less than 400 miles from Kyushu, the island had been Japanese territory since 1868, and it was home to several hundred thousand Japanese civilians. The Battle of Okinawa was fought from April 1 – June 22, 1945. Five U.S. Army divisions, three Marine divisions, and dozens of Navy vessels participated in the 82-day battle. The Japanese stepped up their use of kamikaze attacks, this time sending them at U.S. ships in waves. Seven major kamikaze attacks took place involving 1,500 planes. They took a devastating toll—both physically and psychologically. The U.S. Navy’s dead, at 4,907, exceeded its wounded, primarily because of the kamikaze.

On land, U.S. forces again faced heavily fortified and well-constructed defenses. The Japanese extracted heavy American casualties at one line of defense, and then as the Americans began to gain the upper hand, fell back to another series of fortifications. Japanese defenders and civilians fought to the death (even women with spears) or committed suicide rather than be captured. The civilians had been told the Americans would go on a rampage of killing and raping. About 95,000 Japanese soldiers were killed, and possibly as many as 150,000 civilians died, or 25% of the civilian population. And the fierce resistance took a heavy toll on the Americans; 12,513 were killed on Okinawa, and another 38,916 were wounded.

The increased level of Japanese resistance on Okinawa was of particular significance to military planners, especially the resistance of civilians. This was a concern for the American troops as well. In the Ken Burns documentary The War (2007), a veteran Marine pilot of the Okinawa campaign relates his thoughts at the time about invading the home islands:

By then, our sense of the strangeness of the Japanese opposition had become stronger. And I could imagine every farmer with his pitchfork coming at my guts; every pretty girl with a hand grenade strapped to her bottom, or something; that everyone would be an enemy.

Although the estimates of American casualties in Operation Downfall vary widely, no one doubts that they would have been significant.  A sobering indicator of the government’s expectations is that 500,000 Purple Heart medals (awarded for combat-related wounds) were manufactured in preparation for Operation Downfall.

Argument #1.1: The Atomic Bomb Saved Japanese Lives

A concurrent, though ironic argument supporting the use of the Atomic bomb is that because of the expected Japanese resistance to an invasion of the home island, its use actually saved Japanese lives. Military planners included Japanese casualties in their estimates.  The study done for Secretary of War Stimson predicted five to ten million Japanese fatalities.  There is support for the bomb even among some Japanese.  In 1983, at the annual observance of Hiroshima’s destruction, an aging Japanese professor recalled that at war’s end, due to the extreme food rationing, he had weighed less than 90 pounds and could scarcely climb a flight of stairs. “I couldn’t have survived another month,” he said.  “If the military had its way, we would have fought until all 80 million Japanese were dead.  Only the atomic bomb saved me.  Not me alone, but many Japanese, ironically speaking, were saved by the atomic bomb.”

Argument #1.2: It Was Necessary to Shorten the War

Another concurrent argument supporting the use of the Atomic bomb is that it achieved its primary objective of shortening the war. The bombs were dropped on August 6 and 9. The next day, the Japanese requested a halting of the war.  On August 14 Emperor Hirohito announced to the Japanese people that they would surrender, and the United States celebrated V-J Day (Victory over Japan).  Military planners had wanted the Pacific war finished no later than a year after the fall of Nazi Germany. The rationale was the belief that in a democracy, there is only so much that can reasonably be asked of its citizen soldiers (and of the voting public).

As Army Chief of Staff George Marshall later put it, “a democracy cannot fight a Seven Years’ war.” By the summer of 1945 the American military was exhausted, and the sheer number of troops needed for Operation Downfall meant that not only would the troops in the Pacific have to make one more landing, but even many of those troops whose valor and sacrifice had brought an end to the Nazi Third Reich were to be sent Pacific.  In his 2006 memoir, former 101st Airborne battalion commander Richard Winters reflected on the state of his men as they played baseball in the summer of 1945 in occupied Austria (Winters became something of a celebrity after his portrayal in the extremely popular 2001 HBO series Band of Brothers):

During the baseball games when the men were stripped to their waists, or wearing only shorts, the sight of all those battle scars made me conscious of the fact that other than a handful of men in the battalion who had survived all four campaigns, only a few were lucky enough to be without at least one scar.  Some men had two, three, even four scars on their chests, backs, arms, or legs. Keep in mind that…I was looking only at the men who were not seriously wounded.

Supporters of the bomb wonder if it was reasonable to ask even more sacrifice of these men. Since these veterans are the men whose lives (or wholeness) were, by this argument, saved by the bomb, it is relevant to survey their thoughts on the matter, as written in various war memoirs going back to the 1950s.  The record is mixed. For example, despite Winters’ observation above, he seemed to have reservations about the bomb: “Three days later, on August 14, Japan surrendered.  Apparently the atomic bomb carried as much punch as a regiment of paratroopers.  It seemed inhumane for our national leaders to employ either weapon on the human race.”

His opinion is not shared by other members of Easy Company, some of whom published their own memoirs after the interest generated by Band of Brothers.  William “Wild Bill” Guarnere expressed a very blunt opinion about the bomb in 2007:

We were on garrison duty in France for about a month, and in August, we got great news: we weren’t going to the Pacific.  The U.S. dropped a bomb on Hiroshima, the Japanese surrendered, and the war was over.  We were so relieved.  It was the greatest thing that could have happened. Somebody once said to me that the bomb was the worst thing that ever happened, that the U.S. could have found other ways.  I said, “Yeah, like what? Me and all my buddies jumping in Tokyo, and the Allied forces going in, and all of us getting killed?  Millions more Allied soldiers getting killed?”  When the Japanese bombed Pearl Harbor were they concerned about how many lives they took?  We should have dropped eighteen bombs as far as I’m concerned.  The Japanese should have stayed out of it if they didn’t want bombs dropped. The end of the war was good news to us.  We knew we were going home soon.

Those soldiers with extensive combat experience in the Pacific theater and with first-hand knowledge of Japanese resistance also express conflicting thoughts about the bomb. All of them write of the relief and joy they felt upon first hearing the news. William Manchester, in Goodbye, Darkness: a Memoir of the Pacific War, wrote, “You think of the lives which would have been lost in an invasion of Japan’s home islands—a staggering number of American lives but millions more of Japanese—and you thank God for the atomic bomb.”

But in preparation for writing his 1980 memoir, when Manchester visited Tinian, the small Pacific island from which the Hiroshima mission was launched, he reflected on the “global angst” that Tinian represents.  He writes that while the battle to take Tinian itself was relatively easy, “the aftermath was ominous.” It was also from Tinian that napalm was dropped on Japanese cities, which Manchester describes as “one of thecruelest instruments of war.”  Manchester continues:

This is where the nuclear shadow first appeared.  I feel forlorn, alienated, wholly without empathy for the men who did what they did.  This was not my war…Standing there, notebook in hand; you are shrouded in absolute, inexpressible loneliness.

Two other Pacific memoirs, both published decades ago, resurged in popularity in 2010, owing to their authors’ portrayal in another HBO mini-series, The Pacific (2010).  Eugene Sledge published his combat memoir in 1981.  He describes the moment when they first heard about the atom bomb, having just survived the Okinawa campaign:

We received the news with quiet disbelief coupled with an indescribable sense of relief.  We thought the Japanese would never surrender.  Many refused to believe it.  Sitting around in stunned silence, we remembered our dead.  So many dead.  So many maimed.  So many bright futures consigned to the ashes of the past.  So many dreams lost in the madness that had engulfed us.  Except for a few widely scattered shouts of joy, the survivors sat hollow-eyed and silent, trying to comprehend a world without war.

Robert Leckie, like Manchester, seems to have had conflicting feelings about the bomb in his 1957 memoir Helmet for my Pillow.  When the bomb was dropped, Leckie was recovering from wounds suffered on Peleliu:

Suddenly, secretly, covertly–I rejoiced. For as I lay there in that hospital, I had faced the bleak prospect of returning to the Pacific and the war and the law of averages. But now, I knew the Japanese would have to lay down their arms. The war was over. I had survived. Like a man wielding a submachine gun to defend himself against an unarmed boy, I had survived. So I rejoiced.

But just a paragraph later, Leckie reflects writes:

The suffering of those who lived, the immolation [death by burning] of those who died–that must now be placed in the scales of God’s justice that began to tip so awkwardly against us when the mushroom rose over the world…Dear Father, forgive us for that awful cloud.

 Argument #1.3: Only the Bomb Convinced the Emperor to Intervene

A third concurrent argument defending the bomb is the observation that even after the first two bombs were dropped, and the Russians had declared war, the Japanese still almost did not surrender. The Japanese cabinet convened in emergency session on August 7. Military authorities refused to concede that the Hiroshima bomb was atomic in nature and refused to consider surrender. The following day, Emperor Hirohito privately expressed to Prime Minister Togo his determination that the war should end and the cabinet was convened again on August 9. At this point Prime Minister Suzuki was in agreement, but a unanimous decision was required and three of the military chiefs still refused to admit defeat.

Some in the leadership argued that there was no way the Americans could have refined enough fissionable material to produce more than one bomb.  But then the bombing of Nagasaki had demonstrated otherwise, and a lie told by a downed American pilot convinced War Minister Korechika Anami that the Americans had as many as a hundred bombs. (The official scientific report confirming the bomb was atomic arrived at Imperial Headquarters on the 10th). Even so, hours of meetings and debates lasting well into the early morning hours of the 10th still resulted in a 3-3 deadlock.  Prime Minister Suzuki then took the unprecedented step of asking Emperor Hirohito, who never spoke at cabinet meetings, to break the deadlock. Hirohito responded:

I have given serious thought to the situation prevailing at home and abroad and have concluded that continuing the war can only mean destruction for the nation and prolongation of bloodshed and cruelty in the world. I cannot bear to see my innocent people suffer any longer.

In his 1947 article published in Harper’s, former Secretary of War Stimson expressed his opinion that only the atomic bomb convinced the emperor to step in: “All the evidence I have seen indicates that the controlling factor in the final Japanese decision to accept our terms of surrender was the atomic bomb.”

Emperor Hirohito agreed that Japan should accept the Potsdam Declaration (the terms of surrender proposed by the Americans, discussed below), and then recorded a message on phonograph to the Japanese people.

Japanese hard-liners attempted to suppress this recording, and late on the evening of the 14th, attempted a coup against the Emperor, presumably to save him from himself. The coup failed, but the fanaticism required to make such an attempt is further evidence to bomb supporters that, without the bomb, Japan would never have surrendered. In the end, the military leaders accepted surrender partly because of the Emperor’s intervention, and partly because the atomic bomb helped them “save face” by rationalizing that they had not been defeated by because of a lack of spiritual power or strategic decisions, but by science. In other words, the Japanese military hadn’t lost the war, Japanese science did.

Atomic Bomb Argument 2: The Decision was made by a Committee of Shared Responsibility

Supporters of President Truman’s decision to use atomic weapons point out that the President did not act unilaterally, but rather was supported by a committee of shared responsibility.  The Interim Committee, created in May 1945, was primarily tasked with providing advice to the President on all matters pertaining to nuclear energy.  Most of its work focused on the role of the bomb after the war.  But the committee did consider the question of its use against Japan.

Secretary of War Henry Stimson chaired the committee.  Truman’s personal representative was James F. Byrnes, former U.S. Senator and Truman’s pick to be Secretary of State.  The committee sought the advice of four physicists from the Manhattan Project, including Enrico Fermi and J. Robert Oppenheimer.  The scientific panel wrote, “We see no acceptable alternative to direct military use.” The final recommendation to the President was arrived at on June 1 and is described in the committee meeting log:

Mr. Byrnes recommended, and the Committee agreed, that the Secretary of War should be advised that, while recognizing that the final selection of the target was essentially a military decision, the present view of the Committee was that the bomb should be used against Japan as soon as possible; that it be used on a war plant surrounded by workers’ homes; and that it be used without prior warning.

On June 21, the committee reaffirmed its recommendation with the following wording:

…that the weapon be used against Japan at the earliest opportunity, that it be used without warning, and that it be used on a dual target, namely, a military installation or war plant surrounded by or adjacent to homes or other buildings most susceptible to damage.

Supporters of Truman’s decision thus argue that the President, in dropping the bomb, was simply following the recommendation of the most experienced military, political, and scientific minds in the nation, and to do otherwise would have been grossly negligent.

Atomic Bomb Argument #3: The Japanese Were Given Fair Warning (Potsdam Declaration & Leaflets)

Supporters of Truman’s decision to use the atomic bomb point out that Japan had been given ample opportunity to surrender. On July 26, with the knowledge that the Los Alamos test had been successful, President Truman and the Allies issued a final ultimatum to Japan, known as the Potsdam Declaration (Truman was in Potsdam, Germany at the time).  Although it had been decided by Prime Minster Churchill and President Roosevelt back at the Casablanca Conference that the Allies would accept only unconditional surrender from the Axis, the Potsdam Declaration does lay out some terms of surrender.  The government responsible for the war would be dismantled, there would be a military occupation of Japan, and the nation would be reduced in size to pre-war borders. The military, after being disarmed, would be permitted to return home to lead peaceful lives.  Assurance was given that the allies had no desire to enslave or destroy the Japanese people, but there would be war crimes trials.  Peaceful industries would be allowed to produce goods, and basic freedoms of speech, religion, and thought would be introduced.  The document concluded with an ultimatum: “We call upon the Government of Japan to proclaim now the unconditional surrender of all the Japanese armed forces…the alternative for Japan is prompt and utter destruction.”  To bomb supporters, the Potsdam Declaration was m5ore than fair in its surrender terms and in its warning of what would happen should those terms be rejected.  The Japanese did not respond to the declaration. Additionally, bomb supporters argue that Japanese civilians were warned in advance through millions of leaflets dropped on Japanese cities by U.S. warplanes. In the months preceding the atomic bombings, some 63 million leaflets were dropped on 35 cities target for destruction by U.S. air forces. The Japanese people generally regarded the information on these leaflets as truthful, but anyone caught in possession of one was subject to arrest by the government. Some of the leaflets mentioned the terms of surrender offered in the Potsdam Declaration and urged the civilians to convince Japanese government to accept them—an unrealistic expectation to say the least.

Generally, the leaflets warned that the city was considered a target and urged the civilian populations to evacuate. However, no leaflets specifically warning about a new destructive weapon were dropped until after Hiroshima, and it’s also not clear where U.S. officials thought the entire urban population of 35 Japanese cities could viably relocate to even if they did read and heed the warnings.

Argument 4: The atom bomb was in retaliation for Japanese barbarism

Although it is perhaps not the most civilized of arguments, Americans with an “eye for an eye” philosophy of justice argue that the atomic bomb was payback for the undeniably brutal, barbaric, criminal conduct of the Japanese Army.  Pumped up with their own version of master race theories, the Japanese military committed atrocities throughout Asia and the Pacific. They raped women, forced others to become sexual slaves, murdered civilians, and tortured and executed prisoners. Most famously, in a six-week period following the Japanese capture of the Chinese city of Nanjing, Japanese soldiers (and some civilians) went on a rampage.  They murdered several hundred thousand unarmed civilians, and raped between 20,000-80,000 men, women and children.

With regards to Japanese conduct specific to Americans, there is the obvious “back-stabbing” aspect of the “surprise” attack on Pearl Harbor on December 7, 1941. That the Japanese government was still engaged in good faith diplomatic negotiations with the State Department at the very moment the attack was underway is a singular instance of barbaric behavior that bomb supporters point to as just cause for using the atom bomb. President Truman said as much when he made his August 6 radio broadcast to the nation about Hiroshima: “The Japanese began the war from the air at Pearl Harbor. They have been repaid many fold.”

The infamous “Bataan Death March” provides further rationale for supporters of this argument. Despite having a presence in the Philippines since 1898 and a long-standingstrategic plan for a theoretical war with Japan, the Americans were caught unprepared for the Japanese invasion of the main island of Luzon. After retreating to the rugged Bataan peninsula and holding out for months, it became evident that America had no recourse but to abandon them to their fate.   After General MacArthur removed his command to Australia under the cover of darkness, 78,000 American and Filipino troops surrendered to the Japanese, the largest surrender in American history.

Despite promises from Japanese commanders, the American prisoners were treated inhumanely.  They were force-marched back up the peninsula toward trains and a POW camp beyond.  Along the way they were beaten, deprived of food & water, tortured, buried alive, and executed.  The episode became known at The Bataan Death March. Thousands perished along the way.  And when the survivors reached their destination, Camp O’Donnell, many thousands more died from disease, starvation, and forced labor.  Perhaps fueled by humiliation and a sense of helplessness, few events of WWII aroused such fury in Americans as did the Bataan Death March.  To what extent it may have been a factor in President Truman’s decision is unknown, but it is frequently cited, along with Pearl Harbor, as justification for the payback given out at Hiroshima and Nagasaki to those who started the war. The remaining two arguments in support of the bomb are based on consideration of the unfortunate predicament facing President Truman as the man who inherited both the White House and years of war policy from the late President Roosevelt.

Argument 5: The Manhattan Project Expense Required Use of the Bomb

The Manhattan Project had been initiated by Roosevelt back in 1939, five years before Truman was asked to be on the Democratic ticket.  By the time Roosevelt died in April 1945, almost 2 billion dollars of taxpayer money had been spent on the project.  The Manhattan Project was the most expensive government project in history at that time.  The President’s Chief of Staff, Admiral Leahy, said, “I know FDR would have used it in a minute to prove that he had not wasted $2 billion.” Bomb supporters argue that the pressure to honor the legacy of FDR, who had been in office for so long that many Americans could hardly remember anyone else ever being president, was surely enormous. The political consequences of such a waste of expenditures, once the public found out, would have been disastrous for the Democrats for decades to come. (The counter-argument, of course, is that fear of losing an election is no justification for using such a weapon).

Argument 6: Truman Inherited the War Policy of Bombing Cities

Likewise, the decision to intentionally target civilians, however morally questionable and distasteful, had begun under President Roosevelt, and it was not something that President Truman could realistically be expected to roll back. Precedents for bombing civilians began as early as 1932, when Japanese planes bombed Chapei, the Chinese sector of Shanghai.  Italian forces bombed civilians as part of their conquest of Ethiopia in 1935-1936.  Germany had first bombed civilians as part of an incursion into the Spanish Civil War. At the outbreak of WWII in September 1939, President Roosevelt was troubled by the prospect of what seemed likely to be Axis strategy, and on the day of the German invasion of Poland, he wrote to the governments of France, Germany, Italy, Poland and Great Britain.  Roosevelt said that these precedents for attacking civilians from the air, “has sickened the hearts of every civilized man and woman, and has profoundly shocked the conscience of humanity.” He went on to describe such actions as “inhuman barbarism,” and appealed to the war-makers not to target civilian populations. But Germany bombed cities in Poland in 1939, destroyed the Dutch city of Rotterdam in 1940, and infamously “blitzed” London, Coventry, and other British cities in the summer and fall of the 1940. The British retaliated by bombing German cities.  Allied war leaders rationalized that to win the war, it was necessary to cripple the enemy’s capacity to make war. Since cities contained factories that produced war materials, and since civilians worked in factories, the population of cities (including the “workers’ dwellings” surrounding those factories) were legitimate military targets.

Despite Roosevelt’s “appeal” in 1939, he and the nation had long crossed that moral line by war’s end.  This fact perhaps reveals the psychological effects of killing on all of the war’s participants, and says something about the moral atmosphere in which President Truman found himself upon the President’s death. On February 13, 1945, 1,300 U.S. and British heavy bombers firebombed the German city of Dresden, the center of German art and culture, creating a firestorm that destroyed 15 square miles and killed 25,000 civilians.  Meanwhile, still five weeks before Truman took office; American bombers dropped 2,000 tons of napalm on Tokyo, creating a firestorm with hurricane-force winds.  Flight crews flying high over the 16 square miles of devastation reported smelling burning fleshbelow.  Approximately 125,000 Japanese civilians died in that raid.  By the time the atomic bomb was ready, similar attacks had been launched on the Japanese cities of Nagoya, Osaka, and Kobe.  Quickly running out of targets, the B-29 bombers went back over Tokyo and killed another 80,000 civilians.  Atomic Bomb supporters argue that, although this destruction is distasteful by post-war sensibilities, it had become the norm long before President Truman took office, and the atomic bomb was just one more weapon in the arsenal to be employed under this policy.  To expect the new president, who had to make decisions under enormous pressure, to roll back this policy—to roll back the social norm—was simply not realistic.

 Sources Used and Recommended

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The Atomic Bomb and the End of World War II

A Collection of Primary Sources

Updated National Security Archive Posting Marks 75th Anniversary of the Atomic Bombings of Japan and the End of World War II

Extensive Compilation of Primary Source Documents Explores Manhattan Project, Eisenhower’s Early Misgivings about First Nuclear Use, Curtis LeMay and the Firebombing of Tokyo, Debates over Japanese Surrender Terms, Atomic Targeting Decisions, and Lagging Awareness of Radiation Effects

Washington, D.C., August 4, 2020 –  To mark the 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945, the National Security Archive is updating and reposting one of its most popular e-books of the past 25 years. 

While U.S. leaders hailed the bombings at the time and for many years afterwards for bringing the Pacific war to an end and saving untold thousands of American lives, that interpretation has since been seriously challenged.  Moreover, ethical questions have shrouded the bombings which caused terrible human losses and in succeeding decades fed a nuclear arms race with the Soviet Union and now Russia and others.

Three-quarters of a century on, Hiroshima and Nagasaki remain emblematic of the dangers and human costs of warfare, specifically the use of nuclear weapons.  Since these issues will be subjects of hot debate for many more years, the Archive has once again refreshed its compilation of declassified U.S. government documents and translated Japanese records that first appeared on these pages in 2005.

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Introduction

By William Burr

The 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945 is an occasion for sober reflection. In Japan and elsewhere around the world, each anniversary is observed with great solemnity. The bombings were the first time that nuclear weapons had been detonated in combat operations.  They caused terrible human losses and destruction at the time and more deaths and sickness in the years ahead from the radiation effects. And the U.S. bombings hastened the Soviet Union’s atomic bomb project and have fed a big-power nuclear arms race to this day. Thankfully, nuclear weapons have not been exploded in war since 1945, perhaps owing to the taboo against their use shaped by the dropping of the bombs on Japan. 

Along with the ethical issues involved in the use of atomic and other mass casualty weapons, why the bombs were dropped in the first place has been the subject of sometimes heated debate. As with all events in human history, interpretations vary and readings of primary sources can lead to different conclusions.  Thus, the extent to which the bombings contributed to the end of World War II or the beginning of the Cold War remain live issues.  A significant contested question is whether, under the weight of a U.S. blockade and massive conventional bombing, the Japanese were ready to surrender before the bombs were dropped.  Also still debated is the impact of the Soviet declaration of war and invasion of Manchuria, compared to the atomic bombings, on the Japanese decision to surrender. Counterfactual issues are also disputed, for example whether there were alternatives to the atomic bombings, or would the Japanese have surrendered had a demonstration of the bomb been used to produced shock and awe. Moreover, the role of an invasion of Japan in U.S. planning remains a matter of debate, with some arguing that the bombings spared many thousands of American lives that otherwise would have been lost in an invasion.

Those and other questions will be subjects of discussion well into the indefinite future. Interested readers will continue to absorb the fascinating historical literature on the subject.  Some will want to read declassified primary sources so they can further develop their own thinking about the issues. Toward that end, in 2005, at the time of the 60th anniversary of the bombings, staff at the National Security Archive compiled and scanned a significant number of declassified U.S. government documents to make them more widely available. The documents cover multiple aspects of the bombings and their context.  Also included, to give a wider perspective, were translations of Japanese documents not widely available before.  Since 2005, the collection has been updated. This latest iteration of the collection includes corrections, a few minor revisions, and updated footnotes to take into account recently published secondary literature.

2015 Update

August 4, 2015 – A few months after the atomic bombings of Hiroshima and Nagasaki, General Dwight D.  Eisenhower commented during a social occasion “how he had hoped that the war might have ended without our having to use the atomic bomb.” This virtually unknown evidence from the diary of Robert P. Meiklejohn, an assistant to Ambassador W. Averell Harriman, published for the first time today by the National Security Archive, confirms that the future President Eisenhower had early misgivings about the first use of atomic weapons by the United States. General George C. Marshall is the only high-level official whose contemporaneous (pre-Hiroshima) doubts about using the weapons against cities are on record.

On the 70th anniversary of the bombing of Hiroshima on August 6, 1945, the National Security Archive updates its 2005 publication of the most comprehensive on-line collection of declassified U.S. government documents on the first use of the atomic bomb and the end of the war in the Pacific. This update presents previously unpublished material and translations of difficult-to-find records. Included are documents on the early stages of the U.S. atomic bomb project, Army Air Force General  Curtis LeMay’s report  on the firebombing of Tokyo (March 1945), Secretary of War Henry  Stimson’s requests  for modification of unconditional surrender terms,  Soviet documents  relating to the events, excerpts from the Robert P. Meiklejohn diaries mentioned above, and selections from the diaries of Walter J. Brown, special assistant to Secretary of State James Byrnes.

The original 2005 posting included a wide range of material, including formerly top secret "Magic" summaries of intercepted Japanese communications and the first-ever full translations from the Japanese of accounts of high level meetings and discussions in Tokyo leading to the Emperor’s decision to surrender. Also documented are U.S. decisions to target Japanese cities, pre-Hiroshima petitions by scientists questioning the military use of the A-bomb, proposals for demonstrating the effects of the bomb, debates over whether to modify unconditional surrender terms, reports from the bombing missions of Hiroshima and Nagasaki, and belated top-level awareness of the radiation effects of atomic weapons.

The documents can help readers to make up their own minds about long-standing controversies such as whether the first use of atomic weapons was justified, whether President Harry S. Truman had alternatives to atomic attacks for ending the war, and what the impact of the Soviet declaration of war on Japan was. Since the 1960s, when the declassification of important sources began, historians have engaged in vigorous debate over the bomb and the end of World War II. Drawing on sources at the National Archives and the Library of Congress as well as Japanese materials, this electronic briefing book includes key documents that historians of the events have relied upon to present their findings and advance their interpretations.

The Atomic Bomb and the End of World War II: A Collection of Primary Sources

Seventy years ago this month, the United States dropped atomic bombs on Hiroshima and Nagasaki, the Soviet Union declared war on Japan, and the Japanese government surrendered to the United States and its allies. The nuclear age had truly begun with the first military use of atomic weapons. With the material that follows, the National Security Archive publishes the most comprehensive on-line collection to date of declassified U.S. government documents on the atomic bomb and the end of the war in the Pacific. Besides material from the files of the Manhattan Project, this collection includes formerly “Top Secret Ultra” summaries and translations of Japanese diplomatic cable traffic intercepted under the “Magic” program. Moreover, the collection includes for the first time translations from Japanese sources of high level meetings and discussions in Tokyo, including the conferences when Emperor Hirohito authorized the final decision to surrender. [1]

Ever since the atomic bombs were exploded over Japanese cities, historians, social scientists, journalists, World War II veterans, and ordinary citizens have engaged in intense controversy about the events of August 1945. John Hersey’s  Hiroshima , first published in the New Yorker  in 1946 encouraged unsettled readers to question the bombings while church groups and some commentators, most prominently Norman Cousins, explicitly criticized them. Former Secretary of War Henry Stimson found the criticisms troubling and published an influential justification for the attacks in  Harper’s . [2] During the 1960s the availability of primary sources made historical research and writing possible and the debate became more vigorous. Historians Herbert Feis and Gar Alperovitz raised searching questions about the first use of nuclear weapons and their broader political and diplomatic implications. The controversy, especially the arguments made by Alperovitz and others about “atomic diplomacy” quickly became caught up in heated debates over Cold War “revisionism.” The controversy simmered over the years with major contributions by Martin Sherwin and Barton J. Bernstein but it became explosive during the mid-1990s when curators at the National Air and Space Museum met the wrath of the Air Force Association over a proposed historical exhibit on the Enola Gay. [3] The NASM exhibit was drastically scaled-down but historians and journalist continued to engage in the debate. Alperovitz, Bernstein, and Sherwin made new contributions as did other historians, social scientists, and journalists including Richard B. Frank, Herbert Bix, Sadao Asada, Kai Bird, Robert James Maddox, Sean Malloy, Robert P. Newman, Robert S. Norris, Tsuyoshi Hagesawa, and J. Samuel Walker. [4]

The continued controversy has revolved around the following, among other, questions:

• were the atomic strikes necessary primarily to avert an invasion of Japan in November 1945?
• Did Truman authorize the use of atomic bombs for diplomatic-political reasons-- to intimidate the Soviets--or was his major goal to force Japan to surrender and bring the war to an early end?
• If ending the war quickly was the most important motivation of Truman and his advisers to what extent did they see an “atomic diplomacy” capability as a “bonus”?
• To what extent did subsequent justification for the atomic bomb exaggerate or misuse wartime estimates for U.S. casualties stemming from an invasion of Japan?
• Were there alternatives to the use of the weapons? If there were, what were they and how plausible are they in retrospect? Why were alternatives not pursued?
• How did the U.S. government plan to use the bombs? What concepts did war planners use to select targets? To what extent were senior officials interested in looking at alternatives to urban targets? How familiar was President Truman with the concepts that led target planners chose major cities as targets?
• What did senior officials know about the effects of atomic bombs before they were first used. How much did top officials know about the radiation effects of the weapons?
• Did President Truman make a decision, in a robust sense, to use the bomb or did he inherit a decision that had already been made?
• Were the Japanese ready to surrender before the bombs were dropped? To what extent had Emperor Hirohito prolonged the war unnecessarily by not seizing opportunities for surrender?
• If the United States had been more flexible about the demand for “unconditional surrender” by explicitly or implicitly guaranteeing a constitutional monarchy would Japan have surrendered earlier than it did?
• How decisive was the atomic bombings to the Japanese decision to surrender?
• Was the bombing of Nagasaki unnecessary? To the extent that the atomic bombing was critically important to the Japanese decision to surrender would it have been enough to destroy one city?
• Would the Soviet declaration of war have been enough to compel Tokyo to admit defeat?
• Was the dropping of the atomic bombs morally justifiable?

This compilation will not attempt to answer these questions or use primary sources to stake out positions on any of them. Nor is it an attempt to substitute for the extraordinary rich literature on the atomic bombings and the end of World War II. Nor does it include any of the interviews, documents prepared after the events, and post-World War II correspondence, etc. that participants in the debate have brought to bear in framing their arguments. Originally this collection did not include documents on the origins and development of the Manhattan Project, although this updated posting includes some significant records for context. By providing access to a broad range of U.S. and Japanese documents, mainly from the spring and summer of 1945, interested readers can see for themselves the crucial source material that scholars have used to shape narrative accounts of the historical developments and to frame their arguments about the questions that have provoked controversy over the years. To help readers who are less familiar with the debates, commentary on some of the documents will point out, although far from comprehensively, some of the ways in which they have been interpreted. With direct access to the documents, readers may develop their own answers to the questions raised above. The documents may even provoke new questions.

Contributors to the historical controversy have deployed the documents selected here to support their arguments about the first use of nuclear weapons and the end of World War II. The editor has closely reviewed the footnotes and endnotes in a variety of articles and books and selected documents cited by participants on the various sides of the controversy. [5] While the editor has a point of view on the issues, to the greatest extent possible he has tried to not let that influence document selection, e.g., by selectively withholding or including documents that may buttress one point of view or the other. The task of compilation involved consultation of primary sources at the National Archives, mainly in Manhattan Project files held in the records of the Army Corps of Engineers, Record Group 77, but also in the archival records of the National Security Agency. Private collections were also important, such as the Henry L. Stimson Papers held at Yale University (although available on microfilm, for example, at the Library of Congress) and the papers of W. Averell Harriman at the Library of Congress. To a great extent the documents selected for this compilation have been declassified for years, even decades; the most recent declassifications were in the 1990s.

The U.S. documents cited here will be familiar to many knowledgeable readers on the Hiroshima-Nagasaki controversy and the history of the Manhattan Project. To provide a fuller picture of the transition from U.S.-Japanese antagonism to reconciliation, the editor has done what could be done within time and resource constraints to present information on the activities and points of view of Japanese policymakers and diplomats. This includes a number of formerly top secret summaries of intercepted Japanese diplomatic communications, which enable interested readers to form their own judgments about the direction of Japanese diplomacy in the weeks before the atomic bombings. Moreover, to shed light on the considerations that induced Japan’s surrender, this briefing book includes new translations of Japanese primary sources on crucial events, including accounts of the conferences on August 9 and 14, where Emperor Hirohito made decisions to accept Allied terms of surrender.

[ Editor’s Note: Originally prepared in July 2005 this posting has been updated, with new documents, changes in organization, and other editorial changes. As noted, some documents relating to the origins of the Manhattan Project have been included in addition to entries from the Robert P. Meiklejohn diaries and translations of a few Soviet documents, among other items. Moreover, recent significant contributions to the scholarly literature have been taken into account.]

I. Background on the U.S. Atomic Project

Documents 1A-C: Report of the Uranium Committee

1A . Arthur H. Compton, National Academy of Sciences Committee on Atomic Fission, to Frank Jewett, President, National Academy of Sciences, 17 May 1941, Secret

1B . Report to the President of the National Academy of Sciences by the Academy Committee on Uranium, 6 November 1941, Secret

1C . Vannevar Bush, Director, Office of Scientific Research and Development, to President Roosevelt, 27 November 1941, Secret

Source: National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

This set of documents concerns the work of the Uranium Committee of the National Academy of Sciences, an exploratory project that was the lead-up to the actual production effort undertaken by the Manhattan Project. The initial report, May 1941, showed how leading American scientists grappled with the potential of nuclear energy for military purposes. At the outset, three possibilities were envisioned: radiological warfare, a power source for submarines and ships, and explosives. To produce material for any of those purposes required a capability to separate uranium isotopes in order to produce fissionable U-235. Also necessary for those capabilities was the production of a nuclear chain reaction. At the time of the first report, various methods for producing a chain reaction were envisioned and money was being budgeted to try them out.

Later that year, the Uranium Committee completed its report and OSRD Chairman Vannevar Bush reported the findings to President Roosevelt: As Bush emphasized, the U.S. findings were more conservative than those in the British MAUD report: the bomb would be somewhat “less effective,” would take longer to produce, and at a higher cost. One of the report’s key findings was that a fission bomb of superlatively destructive power will result from bringing quickly together a sufficient mass of element U235.” That was a certainty, “as sure as any untried prediction based upon theory and experiment can be.” The critically important task was to develop ways and means to separate highly enriched uranium from uranium-238. To get production going, Bush wanted to establish a “carefully chosen engineering group to study plans for possible production.” This was the basis of the Top Policy Group, or the S-1 Committee, which Bush and James B. Conant quickly established. [6]

In its discussion of the effects of an atomic weapon, the committee considered both blast and radiological damage. With respect to the latter, “It is possible that the destructive effects on life caused by the intense radioactivity of the products of the explosion may be as important as those of the explosion itself.” This insight was overlooked when top officials of the Manhattan Project considered the targeting of Japan during 1945. [7]

Documents 2A-B: Going Ahead with the Bomb

2A : Vannevar Bush to President Roosevelt, 9 March 1942, with memo from Roosevelt attached, 11 March 1942, Secret

2B : Vannevar Bush to President Roosevelt, 16 December 1942, Secret (report not attached)

Sources: 2A: RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942): 2B: Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

The Manhattan Project never had an official charter establishing it and defining its mission, but these two documents are the functional equivalent of a charter, in terms of presidential approvals for the mission, not to mention for a huge budget. In a progress report, Bush told President Roosevelt that the bomb project was on a pilot plant basis, but not yet at the production stage. By the summer, once “production plants” would be at work, he proposed that the War Department take over the project. In reply, Roosevelt wrote a short memo endorsing Bush’s ideas as long as absolute secrecy could be maintained. According to Robert S. Norris, this was “the fateful decision” to turn over the atomic project to military control. [8]

Some months later, with the Manhattan Project already underway and under the direction of General Leslie Grove, Bush outlined to Roosevelt the effort necessary to produce six fission bombs. With the goal of having enough fissile material by the first half of 1945 to produce the bombs, Bush was worried that the Germans might get there first. Thus, he wanted Roosevelt’s instructions as to whether the project should be “vigorously pushed throughout.” Unlike the pilot plant proposal described above, Bush described a real production order for the bomb, at an estimated cost of a “serious figure”: $400 million, which was an optimistic projection given the eventual cost of $1.9 billion. To keep the secret, Bush wanted to avoid a “ruinous” appropriations request to Congress and asked Roosevelt to ask Congress for the necessary discretionary funds. Initialed by President Roosevelt (“VB OK FDR”), this may have been the closest that he came to a formal approval of the Manhattan Project.

Document 3 : Memorandum by Leslie R. Grove, “Policy Meeting, 5/5/43,” Top Secret

Source:  National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

Document 4 :   Memo from General Groves to the Chief of Staff [Marshall], “Atomic Fission Bombs – Present Status and Expected Progress,” 7 August 1944, Top Secret, excised copy

Source: RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt .  Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over  125,000 people  ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10]  For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

Document 5 : Memorandum from Vannevar Bush and James B. Conant, Office of Scientific Research and Development, to Secretary of War, September 30, 1944, Top Secret

Source: RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

While Groves worried about the engineering and production problems, key War Department advisers were becoming troubled over the diplomatic and political implications of these enormously powerful weapons and the dangers of a global nuclear arms race. Concerned that President Roosevelt had an overly “cavalier” belief about the possibility of maintaining a post-war Anglo-American atomic monopoly, Bush and Conant recognized the limits of secrecy and wanted to disabuse senior officials of the notion that an atomic monopoly was possible. To suggest alternatives, they drafted this memorandum about the importance of the international exchange of information and international inspection to stem dangerous nuclear competition. [11]

Documents 6A-D: President Truman Learns the Secret:

6A : Memorandum for the Secretary of War from General L. R. Groves, “Atomic Fission Bombs,” April 23, 1945

6B : Memorandum discussed with the President, April 25, 1945

6C : [Untitled memorandum by General L.R. Groves, April 25, 1945

6D : Diary Entry, April 25, 1945

Sources: A: RG 77, Commanding General’s file no. 24, tab D; B: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress); C: Source: Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”; D: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from a briefing from Secretary of War Stimson and Manhattan Project chief General Groves, who went through the “back door” to escape the watchful press. Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.” In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize.

With respect to the point about assembling the weapons, the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.” The question whether Truman “inherited assumptions” from the Roosevelt administration that that the bomb would be used has been a controversial one. Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s `decision’ was a decision not to override previous plans to use the bomb.” [12]

II. Targeting Japan

Document 7 : Commander F. L. Ashworth to Major General L.R. Groves, “The Base of Operations of the 509 th  Composite Group,” February 24, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th  Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Document 8 : Headquarters XXI Bomber Command, “Tactical Mission Report, Mission No. 40 Flown 10 March 1945,”n.d., Secret

Source: Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless.  [13]  According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not  to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

The killing of workers in the urban-industrial sector was one of the explicit goals of the air campaign against Japanese cities. According to a Joint Chiefs of Staff report on Japanese target systems, expected results from the bombing campaign included: “The absorption of man-hours in repair and relief; the dislocation of labor by casualty; the interruption of public services necessary to production, and above all the destruction of factories engaged in war industry.” While Stimson would later raise questions about the bombing of Japanese cities, he was largely disengaged from the details (as he was with atomic targeting). [14]

Firebombing raids on other cities followed Tokyo, including Osaka, Kobe, Yokahama, and Nagoya, but with fewer casualties (many civilians had fled the cities). For some historians, the urban fire-bombing strategy facilitated atomic targeting by creating a “new moral context,” in which earlier proscriptions against intentional targeting of civilians had eroded. [15]

Document 9 : Notes on Initial Meeting of Target Committee, May 2, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st  Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction.  [16]

Document 10 : Memorandum from J. R. Oppenheimer to Brigadier General Farrell, May 11, 1945

Source: RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions.  [17]

Document 11 : Memorandum from Major J. A. Derry and Dr. N.F. Ramsey to General L.R. Groves, “Summary of Target Committee Meetings on 10 and 11 May 1945,” May 12, 1945, Top Secret

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city.  [18]

Document 12 : Stimson Diary Entries, May 14 and 15, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

On May 14 and 15, Stimson had several conversations involving S-1 (the atomic bomb); during a talk with Assistant Secretary of War John J. McCloy, he estimated that possession of the bomb gave Washington a tremendous advantage—“held all the cards,” a “royal straight flush”-- in dealing with Moscow on post-war problems: “They can’t get along without our help and industries and we have coming into action a weapon which will be unique.” The next day a discussion of divergences with Moscow over the Far East made Stimson wonder whether the atomic bomb would be ready when Truman met with Stalin in July. If it was, he believed that the bomb would be the “master card” in U.S. diplomacy. This and other entries from the Stimson diary (as well as the entry from the Davies diary that follows) are important to arguments developed by Gar Alperovitz and Barton J. Bernstein, among others, although with significantly different emphases, that in light of controversies with the Soviet Union over Eastern Europe and other areas, top officials in the Truman administration believed that possessing the atomic bomb would provide them with significant leverage for inducing Moscow’s acquiescence in U.S. objectives. [19]

Document 13 : Davies Diary entry for May 21, 1945

Source: Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

While officials at the Pentagon continued to look closely at the problem of atomic targets, President Truman, like Stimson, was thinking about the diplomatic implications of the bomb. During a conversation with Joseph E. Davies, a prominent Washington lawyer and former ambassador to the Soviet Union, Truman said that he wanted to delay talks with Stalin and Churchill until July when the first atomic device had been tested. Alperovitz treated this entry as evidence in support of the atomic diplomacy argument, but other historians, ranging from Robert Maddox to Gabriel Kolko, have denied that the timing of the Potsdam conference had anything to do with the goal of using the bomb to intimidate the Soviets. [20]

Document 14 : Letter, O. C. Brewster to President Truman, 24 May 1945, with note from Stimson to Marshall, 30 May 1945, attached, secret

Source: Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly.  [21]  An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Brewster suggested that Japan could be used as a “target” for a “demonstration” of the bomb, which he did not further define. His implicit preference, however, was for non-use; he wrote that it would be better to take U.S. casualties in “conquering Japan” than “to bring upon the world the tragedy of unrestrained competitive production of this material.”

Document 15 : Minutes of Third Target Committee Meeting – Washington, May 28, 1945, Top Secret

More updates on training missions, target selection, and conditions required for successful detonation over the target. The target would be a city--either Hiroshima, Kyoto (still on the list), or Niigata--but specific “aiming points” would not be specified at that time nor would industrial “pin point” targets because they were likely to be on the “fringes” a city. The bomb would be dropped in the city’s center. “Pumpkins” referred to bright orange, pumpkin-shaped high explosive bombs—shaped like the “Fat Man” implosion weapon--used for bombing run test missions.

Document 16 : General Lauris Norstad to Commanding General, XXI Bomber Command, “509 th  Composite Group; Special Functions,” May 29, 1945, Top Secret

The 509 th  Composite Group’s cover story for its secret mission was the preparation of “Pumpkins” for use in battle. In this memorandum, Norstad reviewed the complex requirements for preparing B-29s and their crew for successful nuclear strikes.

Document 17 : Assistant Secretary of War John J. McCloy, “Memorandum of Conversation with General Marshal May 29, 1945 – 11:45 p.m.,” Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]  

Document 18 : “Notes of the Interim Committee Meeting Thursday, 31 May 1945, 10:00 A.M. to 1:15 P.M. – 2:15 P.M. to 4:15 P.M., ” n.d., Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project, problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.” Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.” Exactly how the mass deaths of civilians would persuade Japanese rulers to surrender was not discussed. Bernstein has argued that this target choice represented an uneasy endorsement of “terror bombing”--the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23]  It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19 : General George A. Lincoln to General Hull, June 4, 1945, enclosing draft, Top Secret

Source: Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.”  [24]

Document 20 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 6, 1945, Top Secret

In a memorandum to George Harrison, Stimson’s special assistant on Manhattan Project matters, Arneson noted actions taken at the recent Interim Committee meetings, including target criterion and an attack “without prior warning.”

Document 21 : Memorandum of Conference with the President, June 6, 1945, Top Secret

Source: Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back).  [25]  As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh.  The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

III. Debates on Alternatives to First Use and Unconditional Surrender

Document 22 : Memorandum from Arthur B. Compton to the Secretary of War, enclosing “Memorandum on `Political and Social Problems,’ from Members of the `Metallurgical Laboratory’ of the University of Chicago,” June 12, 1945, Secret

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock.  [26]

Document 23 : Memorandum from Acting Secretary of State Joseph Grew to the President, “Analysis of Memorandum Presented by Mr. Hoover,” June 13, 1945

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

A former ambassador to Japan, Joseph Grew’s extensive knowledge of Japanese politics and culture informed his stance toward the concept of unconditional surrender. He believed it essential that the United States declare its intention to preserve the institution of the emperor. As he argued in this memorandum to President Truman, “failure on our part to clarify our intentions” on the status of the emperor “will insure prolongation of the war and cost a large number of human lives.” Documents like this have played a role in arguments developed by Alperovitz that Truman and his advisers had alternatives to using the bomb such as modifying unconditional surrender and that anti-Soviet considerations weighed most heavily in their thinking. By contrast, Herbert P. Bix has suggested that the Japanese leadership would “probably not” have surrendered if the Truman administration had spelled out the status of the emperor. [27]

Document 24 : Memorandum from Chief of Staff Marshall to the Secretary of War, 15 June 1945, enclosing “Memorandum of Comments on `Ending the Japanese War,’” prepared by George A. Lincoln, June 14, 1945, Top Secret

Commenting on another memorandum by Herbert Hoover, George A. Lincoln discussed war aims, face-saving proposals for Japan, and the nature of the proposed declaration to the Japanese government, including the problem of defining “unconditional surrender.” Lincoln argued against modifying the concept of unconditional surrender: if it is “phrased so as to invite negotiation” he saw risks of prolonging the war or a “compromise peace.” J. Samuel Walker has observed that those risks help explain why senior officials were unwilling to modify the demand for unconditional surrender. [28]

Document 25 : Memorandum by J. R. Oppenheimer, “Recommendations on the Immediate Use of Nuclear Weapons,” June 16, 1945, Top Secret

In a report to Stimson, Oppenheimer and colleagues on the scientific advisory panel--Arthur Compton, Ernest O. Lawrence, and Enrico Fermi—tacitly disagreed with the report of the “Met Lab” scientists. The panel argued for early military use but not before informing key allies about the atomic project to open a dialogue on “how we can cooperate in making this development contribute to improved international relations.”

Document 26 : “Minutes of Meeting Held at the White House on Monday, 18 June 1945 at 1530,” Top Secret

Source: Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186 th -194 th

With the devastating battle for Okinawa winding up, Truman and the Joint Chiefs stepped back and considered what it would take to secure Japan’s surrender. The discussion depicted a Japan that, by 1 November, would be close to defeat, with great destruction and economic losses produced by aerial bombing and naval blockade, but not ready to capitulate. Marshall believed that the latter required Soviet entry and an invasion of Kyushu, even suggesting that Soviet entry might be the “decisive action levering them into capitulation.” Truman and the Chiefs reviewed plans to land troops on Kyushu on 1 November, which Marshall believed was essential because air power was not decisive. He believed that casualties would not be more than those produced by the battle for Luzon, some 31,000. This account hints at discussion of the atomic bomb (“certain other matters”), but no documents disclose that part of the meeting.

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated.  [29]

According to accounts based on post-war recollections and interviews, during the meeting McCloy raised the possibility of winding up the war by guaranteeing the preservation of the emperor albeit as a constitutional monarch. If that failed to persuade Tokyo, he proposed that the United States disclose the secret of the atomic bomb to secure Japan’s unconditional surrender. While McCloy later recalled that Truman expressed interest, he said that Secretary of State Byrnes squashed the proposal because of his opposition to any “deals” with Japan. Yet, according to Forrest Pogue’s account, when Truman asked McCloy if he had any comments, the latter opened up a discussion of nuclear weapons use by asking “Why not use the bomb?” [30]

Document 27 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 25, 1945, Top Secret

For Harrison’s convenience, Arneson summarized key decisions made at the 21 June meeting of the Interim Committee, including a recommendation that President Truman use the forthcoming conference of allied leaders to inform Stalin about the atomic project. The Committee also reaffirmed earlier recommendations about the use of the bomb at the “earliest opportunity” against “dual targets.” In addition, Arneson included the Committee’s recommendation for revoking part two of the 1944 Quebec agreement which stipulated that the neither the United States nor Great Britain would use the bomb “against third parties without each other’s consent.” Thus, an impulse for unilateral control of nuclear use decisions predated the first use of the bomb.

Document 28 : Memorandum from George L. Harrison to Secretary of War, June 26, 1945, Top Secret

Source: RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Reminding Stimson about the objections of some Manhattan project scientists to military use of the bomb, Harrison summarized the basic arguments of the Franck report. One recommendation shared by many of the scientists, whether they supported the report or not, was that the United States inform Stalin of the bomb before it was used. This proposal had been the subject of positive discussion by the Interim Committee on the grounds that Soviet confidence was necessary to make possible post-war cooperation on atomic energy.

Document 29 : Memorandum from George L. Harrison to Secretary of War, June 28, 1945, Top Secret, enclosing Ralph Bard’s “Memorandum on the Use of S-1 Bomb,” June 27, 1945

Under Secretary of the Navy Ralph Bard joined those scientists who sought to avoid military use of the bomb; he proposed a “preliminary warning” so that the United States would retain its position as a “great humanitarian nation.” Alperovitz cites evidence that Bard discussed his proposal with Truman who told him that he had already thoroughly examined the problem of advanced warning. This document has also figured in the argument framed by Barton Bernstein that Truman and his advisers took it for granted that the bomb was a legitimate weapon and that there was no reason to explore alternatives to military use. Bernstein, however, notes that Bard later denied that he had a meeting with Truman and that White House appointment logs support that claim. [31]

Document 30 : Memorandum for Mr. McCloy, “Comments re: Proposed Program for Japan,” June 28, 1945, Draft, Top Secret

Source: RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Despite the interest of some senior officials such as Joseph Grew, Henry Stimson, and John J. McCloy in modifying the concept of unconditional surrender so that the Japanese could be sure that the emperor would be preserved, it remained a highly contentious subject. For example, one of McCloy’s aides, Colonel Fahey, argued against modification of unconditional surrender (see “Appendix ‘C`”).

Document 31 : Assistant Secretary of War John J. McCloy to Colonel Stimson, June 29, 1945, Top Secret

McCloy was part of a drafting committee at work on the text of a proclamation to Japan to be signed by heads of state at the forthcoming Potsdam conference. As McCloy observed the most contentious issue was whether the proclamation should include language about the preservation of the emperor: “This may cause repercussions at home but without it those who seem to know the most about Japan feel there would be very little likelihood of acceptance.”

Document 32 : Memorandum, “Timing of Proposed Demand for Japanese Surrender,” June 29, 1945, Top Secret

Probably the work of General George A. Lincoln at Army Operations, this document was prepared a few weeks before the Potsdam conference when senior officials were starting to finalize the text of the declaration that Truman, Churchill, and Chiang would issue there. The author recommended issuing the declaration “just before the bombardment program [against Japan] reaches its peak.” Next to that suggestion, Stimson or someone in his immediate office, wrote “S1”, implying that the atomic bombing of Japanese cities was highly relevant to the timing issue. Also relevant to Japanese thinking about surrender, the author speculated, was the Soviet attack on their forces after a declaration of war.

Document 33 : Stimson memorandum to The President, “Proposed Program for Japan,” 2 July 1945, Top Secret

Source: Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor.  [32]

Document 34 : Minutes, Secretary’s Staff Committee, Saturday Morning, July 7, 1945, 133d Meeting, Top Secret

Source: Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

The possibility of modifying the concept of unconditional surrender so that it guaranteed the continuation of the emperor remained hotly contested within the U.S. government. Here senior State Department officials, Under Secretary Joseph Grew on one side, and Assistant Secretary Dean Acheson and Archibald MacLeish on the other, engaged in hot debate.

Document 35 : Combined Chiefs of Staff, “Estimate of the Enemy Situation (as of 6 July 1945, C.C.S 643/3, July 8, 1945, Secret (Appendices Not Included)

Source: RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

This review of Japanese capabilities and intentions portrays an economy and society under “tremendous strain”; nevertheless, “the ground component of the Japanese armed forces remains Japan’s greatest military asset.” Alperovitz sees statements in this estimate about the impact of Soviet entry into the war and the possibility of a conditional surrender involving survival of the emperor as an institution as more evidence that the policymakers saw alternatives to nuclear weapons use. By contrast, Richard Frank takes note of the estimate’s depiction of the Japanese army’s terms for peace: “for surrender to be acceptable to the Japanese army it would be necessary for the military leaders to believe that it would not entail discrediting the warrior tradition and that it would permit the ultimate resurgence of a military in Japan.” That, Frank argues, would have been “unacceptable to any Allied policy maker.” [33]

Document 36 : Cable to Secretary of State from Acting Secretary Joseph Grew, July 16, 1945, Top Secret

Source: Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

On the eve of the Potsdam Conference, a State Department draft of the proclamation to Japan contained language which modified unconditional surrender by promising to retain the emperor. When former Secretary of State Cordell Hull learned about it he outlined his objections to Byrnes, arguing that it might be better to wait “the climax of allied bombing and Russia’s entry into the war.” Byrnes was already inclined to reject that part of the draft, but Hull’s argument may have reinforced his decision.

Document 37 : Letter from Stimson to Byrnes, enclosing memorandum to the President, “The Conduct of the War with Japan,” 16 July 1945, Top Secret

Source: Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor .  Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38 : R. E. Lapp, Leo Szilard et al., “A Petition to the President of the United States,” July 17, 1945

On the eve of the Potsdam conference, Leo Szilard circulated a petition as part of a final effort to discourage military use of the bomb. Signed by about 68 Manhattan Project scientists, mainly physicists and biologists (copies with the remaining signatures are in the archival file), the petition did not explicitly reject military use, but raised questions about an arms race that military use could instigate and requested Truman to publicize detailed terms for Japanese surrender. Truman, already on his way to Europe, never saw the petition. [35]

IV. The Japanese Search for Soviet Mediation

Documents 39A-B: Magic

39A : William F. Friedman, Consultant (Armed Forces Security Agency), “A Short History of U.S. COMINT Activities,” 19 February 1952, Top Secret

39B :“Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1204 – July 12, 1945, Top Secret Ultra

Sources: A: National Security Agency Mandatory declassification review release; B: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by  William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th  century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

The 12 July 1945 “Magic” summary includes a report on a cable from Japanese Foreign Minister Shigenori Togo to Ambassador Naotake Sato in Moscow concerning the Emperor’s decision to seek Soviet help in ending the war. Not knowing that the Soviets had already made a commitment to their Allies to declare war on Japan, Tokyo fruitlessly pursued this option for several weeks. The “Magic” intercepts from mid-July have figured in Gar Alperovitz’s argument that Truman and his advisers recognized that the Emperor was ready to capitulate if the Allies showed more flexibility on the demand for unconditional surrender. This point is central to Alperovitz’s thesis that top U.S. officials recognized a “two-step logic”: relaxing unconditional surrender and a Soviet declaration of war would have been enough to induce Japan’s surrender without the use of the bomb. [37]

Document 40 : John Weckerling, Deputy Assistant Chief of Staff, G-2, July 12, 1945, to Deputy Chief of Staff, “Japanese Peace Offer,” 13 July 1945, Top Secret Ultra

Source: RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

The day after the Togo message was reported, Army intelligence chief Weckerling proposed several possible explanations of the Japanese diplomatic initiative. Robert J. Maddox has cited this document to support his argument that top U.S. officials recognized that Japan was not close to surrender because Japan was trying to “stave off defeat.” In a close analysis of this document, Tsuyoshi Hasegawa, who is also skeptical of claims that the Japanese had decided to surrender, argues that each of the three possibilities proposed by Weckerling “contained an element of truth, but none was entirely correct”. For example, the “governing clique” that supported the peace moves was not trying to “stave off defeat” but was seeking Soviet help to end the war. [38]

Document 41 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1205 – July 13, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

The day after he told Sato about the current thinking on Soviet mediation, Togo requested the Ambassador to see Soviet Foreign Minister Vyacheslav Molotov and tell him of the Emperor’s “private intention to send Prince Konoye as a Special Envoy” to Moscow. Before he received Togo’s message, Sato had already met with Molotov on another matter.

Document 42 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1210 – July 17, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Another intercept of a cable from Togo to Sato shows that the Foreign Minister rejected unconditional surrender and that the Emperor was not “asking the Russian’s mediation in anything like unconditional surrender.” Incidentally, this “`Magic’ Diplomatic Summary” indicates the broad scope and capabilities of the program; for example, it includes translations of intercepted French messages (see pages 8-9).

Document 43 : Admiral Tagaki Diary Entry for July 20, 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

In 1944 Navy minister Mitsumasa Yonai ordered rear admiral Sokichi Takagi to go on sick leave so that he could undertake a secret mission to find a way to end the war. Tagaki was soon at the center of a cabal of Japanese defense officials, civil servants, and academics, which concluded that, in the end, the emperor would have to “impose his decision on the military and the government.” Takagi kept a detailed account of his activities, part of which was in diary form, the other part of which he kept on index cards. The material reproduced here gives a sense of the state of play of Foreign Minister Togo’s attempt to secure Soviet mediation. Hasegawa cited it and other documents to make a larger point about the inability of the Japanese government to agree on “concrete” proposals to negotiate an end to the war. [39]

The last item discusses Japanese contacts with representatives of the Office of Strategic Services (OSS) in Switzerland. The reference to “our contact” may refer to Bank of International Settlements economist Pers Jacobbson who was in touch with Japanese representatives to the Bank as well as Gero von Gävernitz, then on the staff, but with non-official cover, of OSS station chief Allen Dulles. The contacts never went far and Dulles never received encouragement to pursue them. [40]

V. The Trinity Test

Document 44 : Letter from Commissar of State Security First Rank, V. Merkulov, to People’s Commissar for Internal Affairs L. P. Beria, 10 July 1945, Number 4305/m, Top Secret (translation by Anna Melyaskova)

Source:  L.D. Riabev, ed.,  Atomnyi Proekt SSSR  (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

As indicated by the L.D. Riabev’s notes, it is possible that Beria’s copy of this letter ended up in Stalin’s papers. That the original copy is missing from Beria’s papers suggests that he may have passed it on to Stalin before the latter left for the Potsdam conference. [41]

Document 45 : Telegram War [Department] 33556, from Harrison to Secretary of War, July 17, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the  Trinity Test  of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46 : Memorandum from General L. R. Groves to Secretary of War, “The Test,” July 18, 1945, Top Secret, Excised Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

General Groves prepared for Stimson, then at Potsdam, a detailed account of the Trinity test. [43]

VI. The Potsdam Conference

Document 47 : Truman’s Potsdam Diary

Source: Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,”  Foreign Service Journal , July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

The diary entries cover July 16, 17, 18, 20, 25, 26, and 30 and include Truman’s thinking about a number of issues and developments, including his reactions to Churchill and Stalin, the atomic bomb and how it should be targeted, the possible impact of the bomb and a Soviet declaration of war on Japan, and his decision to tell Stalin about the bomb. Receptive to pressure from Stimson, Truman recorded his decision to take Japan’s “old capital” (Kyoto) off the atomic bomb target list. Barton Bernstein and Richard Frank, among others, have argued that Truman’s assertion that the atomic targets were “military objectives” suggested that either he did not understand the power of the new weapons or had simply deceived himself about the nature of the targets. Another statement—“Fini Japs when that [Soviet entry] comes about”—has also been the subject of controversy over whether it meant that Truman thought it possible that the war could end without an invasion of Japan. [45]

Document 48 : Stimson Diary entries for July 16 through 25, 1945

Stimson did not always have Truman’s ear, but historians have frequently cited his diary when he was at the Potsdam conference. There Stimson kept track of S-1 developments, including news of the successful first test (see entry for July 16) and the ongoing deployments for nuclear use against Japan. When Truman received a detailed account of the test, Stimson reported that the “President was tremendously pepped up by it” and that “it gave him an entirely new feeling of confidence” (see entry for July 21). Whether this meant that Truman was getting ready for a confrontation with Stalin over Eastern Europe and other matters has also been the subject of debate.

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46]  During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49 : Walter Brown Diaries, July 10-August 3, 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

Walter Brown, who served as special assistant to Secretary of State Byrnes, kept a diary which provided considerable detail on the Potsdam conference and the growing concerns about Soviet policy among top U.S. officials. This document is a typed-up version of the hand-written original (which Brown’s family has provided to Clemson University). That there may be a difference between the two sources becomes evident from some of the entries; for example, in the entry for July 18, 1945 Brown wrote: "Although I knew about the atomic bomb when I wrote these notes, I dared not place it in writing in my book.”

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For  Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1214 – July 22, 1945, Top Secret Ultra

This “Magic” summary includes messages from both Togo and Sato. In a long and impassioned message, the latter argued why Japan must accept defeat: “it is meaningless to prove one’s devotion [to the Emperor] by wrecking the State.” Togo rejected Sato’s advice that Japan could accept unconditional surrender with one qualification: the “preservation of the Imperial House.” Probably unable or unwilling to take a soft position in an official cable, Togo declared that “the whole country … will pit itself against the enemy in accordance with the Imperial Will as long as the enemy demands unconditional surrender.”

Document 51 : Forrestal Diary Entry, July 24, 1945, “Japanese Peace Feelers”

Source: Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.”  [49]

Document 52 : Davies Diary entry for July 29, 1945

S ource: Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

Having been asked by Truman to join the delegation to the Potsdam conference, former-Ambassador Davies sat at the table with the Big Three throughout the discussions. This diary entry has figured in the argument that Byrnes believed that the atomic bomb gave the United States a significant advantage in negotiations with the Soviet Union. Plainly Davies thought otherwise. [50]

VII. Debates among the Japanese – Late July/Early August 1945

Document 53 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1221- July 29, 1945, Top Secret Ultra

In the  Potsdam Declaration  the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51]  Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1222 – July 30, 1945, Top Secret Ultra

This report included an intercept of a message from Sato reporting that it was impossible to see Molotov and that unless the Togo had a “concrete and definite plan for terminating the war” he saw no point in attempting to meet with him.

Document 55 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1225 – August 2, 1945, Top Secret Ultra

An intercepted message from Togo to Sato showed that Tokyo remained interested in securing Moscow’s good office but that it “is difficult to decide on concrete peace conditions here at home all at once.” “[W]e are exerting ourselves to collect the views of all quarters on the matter of concrete terms.” Barton Bernstein, Richard Frank, and Tsuyoshi Hasegawa, among others, have argued that the “Magic” intercepts from the end of July and early August show that the Japanese were far from ready to surrender. According to Herbert Bix, for months Hirohito had believed that the “outlook for a negotiated peace could be improved if Japan fought and won one last decisive battle,” thus, he delayed surrender, continuing to “procrastinate until the bomb was dropped and the Soviets attacked.” [52]

Document 56 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1226 - August 3, 1945, Top Secret Ultra

This summary included intercepts of Japanese diplomatic reporting on the Soviet buildup in the Far East as well as a naval intelligence report on Anglo-American discussions of U.S. plans for the invasion of Japan. Part II of the summary includes the rest of Togo’s 2 August cable which instructed Sato to do what he could to arrange an interview with Molotov.

Document 57 : Walter Brown Meeting Notes, August 3, 1945

Historians have used this item in the papers of Byrne’s aide, Walter Brown, to make a variety of points. Richard Frank sees this brief discussion of Japan’s interest in Soviet diplomatic assistance as crucial evidence that Admiral Leahy had been sharing “MAGIC” information with President Truman. He also points out that Truman and his colleagues had no idea what was behind Japanese peace moves, only that Suzuki had declared that he would “ignore” the Potsdam Declaration. Alperovitz, however, treats it as additional evidence that “strongly suggests” that Truman saw alternatives to using the bomb. [53]

Document 58 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 502, 4 August 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

This “Far East Summary” included reports on the Japanese Army’s plans to disperse fuel stocks to reduce vulnerability to bombing attacks, the text of a directive by the commander of naval forces on “Operation Homeland,” the preparations and planning to repel a U.S. invasion of Honshu, and the specific identification of army divisions located in, or moving into, Kyushu. Both Richard Frank and Barton Bernstein have used intelligence reporting and analysis of the major buildup of Japanese forces on southern Kyushu to argue that U.S. military planners were so concerned about this development that by early August 1945 they were reconsidering their invasion plans. [54]

Document 59 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1228 – August 5, 1945, Top Secret Ultra

This summary included several intercepted messages from Sato, who conveyed his despair and exasperation over what he saw as Tokyo’s inability to develop terms for ending the war: “[I]f the Government and the Military dilly-dally in bringing this resolution to fruition, then all Japan will be reduced to ashes.” Sato remained skeptical that the Soviets would have any interest in discussions with Tokyo: “it is absolutely unthinkable that Russia would ignore the Three Power Proclamation and then engage in conversations with our special envoy.”

VIII. The Execution Order

Documents 60a-d: Framing the Directive for Nuclear Strikes:

60A . Cable VICTORY 213 from Marshall to Handy, July 22, 1945, Top Secret

60B . Memorandum from Colonel John Stone to General Arnold, “Groves Project,” 24 July 1945, Top Secret

60C . Cable WAR 37683 from General Handy to General Marshal, enclosing directive to General Spatz, July 24, 1945, Top Secret

60D . Cable VICTORY 261 from Marshall to General Handy, July 25, 1945, 25 July 1945, Top Secret

60E . General Thomas T. Handy to General Carl Spaatz, July 26, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e ((copies from microfilm)

Top Army Air Force commanders may not have wanted to take responsibility for the first use of nuclear weapons on urban targets and sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55]  On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 61 : Memorandum from Major General L. R. Groves to Chief of Staff, July 30, 1945, Top Secret, Sanitized Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56]  Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Documents 62A-C: Weather delays

62A . CG 313 th  Bomb Wing, Tinian cable APCOM 5112 to War Department, August 3, 1945, Top Secret

62B . CG 313 th  Bomb Wing, Tinian cable APCOM 5130 to War Department, August 4, 1945, Top Secret

62C . CG 313 th  Bomb Wing, Tinian cable APCOM 5155 to War Department, August 4, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

The Hiroshima “operation” was originally slated to begin in early August depending on local conditions. As these cables indicate, reports of unfavorable weather delayed the plan. The second cable on 4 August shows that the schedule advanced to late in the evening of 5 August. The handwritten transcriptions are on the original archival copies.

IX. The First Nuclear Strikes and their Impact

Document 63 : Memorandum from General L. R. Groves to the Chief of Staff, August 6, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Two days after the bombing of Hiroshima, Groves provided Chief of Staff Marshall with a report which included messages from Captain William S. Parsons and others about the impact of the detonation which, through prompt radiation effects, fire storms, and blast effects, immediately killed at least 70,000, with many dying later from radiation sickness and other causes. [57]

How influential the atomic bombings of Hiroshima and later Nagasaki compared to the impact of the Soviet declaration of war were to the Japanese decision to surrender has been the subject of controversy among historians. Sadao Asada emphasizes the shock of the atomic bombs, while Herbert Bix has suggested that Hiroshima and the Soviet declaration of war made Hirohito and his court believe that failure to end the war could lead to the destruction of the imperial house. Frank and Hasegawa divide over the impact of the Soviet declaration of war, with Frank declaring that the Soviet intervention was “significant but not decisive” and Hasegawa arguing that the two atomic bombs “were not sufficient to change the direction of Japanese diplomacy. The Soviet invasion was.” [58]

Document 64 : Walter Brown Diary Entry, 6 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the  U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65 : Directive from the Supreme Command Headquarters to the Commander-in-Chief of the Soviet Forces in the Far East on the Start of Combat Operations, No. 11122, Signed by [Communist Party General Secretary Joseph] Stalin and [Chief of General Staff A.I.] Antonov, 7 August 1945 (translation by Anna Melyakova)

Source: V. A. Zolotarev, ed.,  Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody ( Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

To keep his pledge at Yalta to enter the war against Japan and to secure the territorial concessions promised at the conference (e.g., Soviet annexation of the Kuriles and southern Sakhalin and a Soviet naval base at Port Arthur, etc.) Stalin considered various dates to schedule an attack. By early August he decided that 9-10 August 1945 would be the best dates for striking Japanese forces in Manchuria. In light of Japan’s efforts to seek Soviet mediation, Stalin wanted to enter the war quickly lest Tokyo reach a compromise peace with the Americans and the British at Moscow’s expense. But on 7 August, Stalin changed the instructions: the attack was to begin the next day. According to David Holloway, “it seems likely that the atomic bombing of Hiroshima the day before that impelled [Stalin] to speed up Soviet entry into the war” and “secure the gains promised at Yalta.” [59]

Document 66 : Memorandum of Conversation, “Atomic Bomb,” August 7, 1945

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

The Soviets already knew about the U.S. atomic project from espionage sources in the United States and Britain so Molotov’s comment to Ambassador Harriman about the secrecy surrounding the U.S. atomic project can be taken with a grain of salt, although the Soviets were probably unaware of specific plans for nuclear use.

Documents 67A-B:  Early High-level Reactions to the Hiroshima Bombing

67A : Cabinet Meeting and Togo's Meeting with the Emperor, August 7-8, 1945 Source: Gaimusho (Ministry of Foreign Affairs) ed.  Shusen Shiroku  (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

67B : Admiral Tagaki Diary Entry for Wednesday, August 8 , 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day.  [59a]

An entry from Admiral Tagaki's diary for August 8 conveys more information on the mood in elite Japanese circles after Hiroshima, but before the Soviet declaration of war and the bombing of Nagasaki. Seeing the bombing of Hiroshima as a sign of a worsening situation at home, Tagaki worried about further deterioration. Nevertheless, his diary suggests that military hard-liners were very much in charge and that Prime Minister Suzuki was talking tough against surrender, by evoking last ditch moments in Japanese history and warning of the danger that subordinate commanders might not obey surrender orders. The last remark aggravated Navy Minister Yonai who saw it as irresponsible. That the Soviets had made no responses to Sato's request for a meeting was understood as a bad sign; Yonai realized that the government had to prepare for the possibility that Moscow might not help. One of the visitors mentioned at the beginning of the entry was Iwao Yamazaki who became Minister of the Interior in the next cabinet.

Document 68 : Navy Secretary James Forrestal to President Truman, August 8, 1945

General Douglas MacArthur had been slated as commander for military operations against Japan’s mainland, this letter to Truman from Forrestal shows that the latter believed that the matter was not settled. Richard Frank sees this as evidence of the uncertainty felt by senior officials about the situation in early August; Forrestal would not have been so “audacious” to take an action that could ignite a “political firestorm” if he “seriously thought the end of the war was near.”

Document 69 : Memorandum of Conversation, “Far Eastern War and General Situation,” August 8, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Shortly after the Soviets declared war on Japan, in line with commitments made at the Yalta and Potsdam conferences, Ambassador Harriman met with Stalin, with George Kennan keeping the U.S. record of the meeting. After Stalin reviewed in considerable detail, Soviet military gains in the Far East, they discussed the possible impact of the atomic bombing on Japan’s position (Nagasaki had not yet been attacked) and the dangers and difficulty of an atomic weapons program. According to Hasegawa, this was an important, even “startling,” conversation: it showed that Stalin “took the atomic bomb seriously”; moreover, he disclosed that the Soviets were working on their own atomic program. [60]

Document 70 : Entries for 8-9 August, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211 , Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946 , Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Robert P. Meiklejohn, who worked as Ambassador W. A. Harriman’s administrative assistant at the U.S. Embassies in Moscow and London during and after World War II, kept a detailed diary of his experiences and observations. The entries for 8 and 9 August, prepared in light of the bombing of Hiroshima, include discussion of the British contribution to the Manhattan Project, Harriman (“his nibs’”) report on his meeting with Molotov about the Soviet declaration of war, and speculation about the impact of the bombing of Hiroshima on the Soviet decision. According to Meiklejohn, “None of us doubt that the atomic bomb speeded up the Soviets’ declaration of war.”

Document 71 : Memorandum of Conference with the President, August 8, 1945 at 10:45 AM

At their first meeting after the dropping of the bomb on Hiroshima, Stimson briefed Truman on the scale of the destruction, with Truman recognizing the “terrible responsibility” that was on his shoulders. Consistent with his earlier attempts, Stimson encouraged Truman to find ways to expedite Japan’s surrender by using “kindness and tact” and not treating them in the same way as the Germans. They also discussed postwar legislation on the atom and the pending Henry D. Smyth report on the scientific work underlying the Manhattan project and postwar domestic controls of the atom.

Documents 72A-C: The Attack on Nagasaki:

72A . Cable APCOM 5445 from General Farrell to O’Leary [Groves assistant], August 9, 1945, Top Secret

72B . COMGENAAF 8 cable CMDW 576 to COMGENUSASTAF, for General Farrell, August 9, 1945, Top secret

72C . COMGENAAF 20 Guam cable AIMCCR 5532 to COMGENUSASTAF Guam, August 10, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

The prime target for the second atomic attack was Kokura, which had a large army arsenal and ordnance works, but various problems ruled that city out; instead, the crew of the B-29 that carried “Fat Man” flew to an alternate target at Nagasaki. These cables are the earliest reports of the mission; the bombing of Nagasaki killed immediately at least 39,000 people, with more dying later. According to Frank, the “actual total of deaths due to the atomic bombs will never be known,” but the “huge number” ranges somewhere between 100,000 and 200,000 people. Barton J. Bernstein and Martin Sherwin have argued that if top Washington policymakers had kept tight control of the delivery of the bomb instead of delegating it to Groves the attack on Nagasaki could have been avoided. The combination of the first bomb and the Soviet declaration of war would have been enough to induce Tokyo’s surrender. By contrast, Maddox argues that Nagasaki was necessary so that Japanese “hardliners” could not “minimize the first explosion” or otherwise explain it away. [61]

Documents 73A-B: Ramsey Letter from Tinian Island

73A : Letter from Norman Ramsey to J. Robert Oppenheimer, undated [mid-August 1945], Secret, excerpts Source: Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

73B : Transcript of the letter prepared by editor.

Ramsey, a physicist, served as deputy director of the bomb delivery group, Project Alberta. This personal account, written on Tinian, reports his fears about the danger of a nuclear accident, the confusion surrounding the Nagasaki attack, and early Air Force thinking about a nuclear strike force.

X. Toward Surrender

Document 74 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 507, August 9, 1945

Within days after the bombing of Hiroshima, U.S. military intelligence intercepted Japanese reports on the destruction of the city. According to an “Eyewitness Account (and Estimates Heard) … In Regard to the Bombing of Hiroshima”: “Casualties have been estimated at 100,000 persons.”

Document 75 : “Hoshina Memorandum” on the Emperor’s “Sacred Decision [ go-seidan] ,” 9-10 August, 1945

Source: Zenshiro Hoshina,  Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku  [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made  go-seidan  [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Despite the bombing of Hiroshima, the Soviet declaration of war, and growing worry about domestic instability, the Japanese cabinet (whose decisions required unanimity) could not form a consensus to accept the Potsdam Declaration. Members of the Supreme War Council—“the Big Six” [62] —wanted the reply to Potsdam to include at least four conditions (e.g., no occupation, voluntary disarmament); they were willing to fight to the finish. The peace party, however, deftly maneuvered to break the stalemate by persuading a reluctant emperor to intervene. According to Hasegawa, Hirohito had become convinced that the preservation of the monarchy was at stake. Late in the evening of 9 August, the emperor and his advisers met in the bomb shelter of the Imperial Palace.

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the  kokutai  (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the  kokutai  narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the  kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76 :“Magic’ – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 508, August 10, 1945

More intercepted messages on the bombing of Hiroshima.

Documents 77A-B: The First Japanese Offer Intercepted

77A . “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1233 – August 10, 1945, Top Secret Ultra

77B . Translation of intercepted Japanese messages, circa 10 August 10, 1945, Top Secret Ultra

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic. A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78 : Diary Entry, Friday, August 10, 1945, Henry Wallace Diary

Source: Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the  Byrnes note .

Secretary of Commerce (and former Vice President) Henry Wallace provided a detailed report on the cabinet meeting where Truman and his advisers discussed the Japanese surrender offer, Russian moves into Manchuria, and public opinion on “hard” surrender terms. With Japan close to capitulation, Truman asserted presidential control and ordered a halt to atomic bombings. Barton J. Bernstein has suggested that Truman’s comment about “all those kids” showed his belated recognition that the bomb caused mass casualties and that the target was not purely a military one. [64]

Document 79 : Entries for 10-11 August, Robert P. Meiklejohn Diary

In these entries, Meiklejohn discussed how he and others in the Moscow Embassy learned about the bombing of Nagasaki from the “OWI Bulletin.” Entries for 10 and 11 August cover discussion at the Embassy about the radio broadcast announcing that Japan would surrender as long the Emperor’s status was not affected. Harriman opined that “surrender is in the bag” because of the Potsdam Declaration’s provision that the Japanese could “choose their own form of government, which would probably include the Emperor.” Further, “the only alternative to the Emperor is Communism,” implying that an official role for the Emperor was necessary to preserve social stability and prevent social revolution.

Document 80 : Stimson Diary Entries, Friday and Saturday, August 10 and 11, 1945

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status.  The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81 : Entries from Walter Brown Diary, 10-11 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary .  According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82 : General L. R. Groves to Chief of Staff George C. Marshall,  August 10, 1945, Top Secret, with a hand-written note by General Marshall

Source: George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83 : Memorandum of Conversation, “Japanese Surrender Negotiations,” August 10, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Japan’s prospective surrender was the subject of detailed discussion between Harriman, British Ambassador Kerr, and Soviet Foreign Minister Molotov during the evening of August 10 (with a follow-up meeting occurring at 2 a.m.). In the course of the conversation, Harriman received a message from Washington that included the proposed U.S. reply and a request for Soviet support of the reply. After considerable pressure from Harriman, the Soviets signed off on the reply but not before tensions surfaced over the control of Japan--whether Moscow would have a Supreme Commander there as well. This marked the beginning of a U.S.-Soviet “tug of war” over occupation arrangements for Japan. [66]

Document 84 : Admiral Tagaki Diary Entry for 12 August [1945] Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

As various factions in the government maneuvered on how to respond to the Byrnes note, Navy Minister Yonai and Admiral Tagaki discussed the latest developments. Yonai was upset that Chief of Staff Yoshijiro Umezu and naval chief Suemu Toyada had sent the emperor a memorandum arguing that acceptance of the Brynes note would “desecrate the emperor’s dignity” and turn Japan into virtually a “slave nation.” The emperor chided Umezu and Toyoda for drawing hasty conclusions; in this he had the support of Yonai, who also dressed them down. As Yonai explained to Tagaki, he had also confronted naval vice Chief Takijiro Onishi to make sure that he obeyed any decision by the Emperor. Yonai made sure that Takagi understood his reasons for bringing the war to an end and why he believed that the atomic bomb and the Soviet declaration of war had made it easier for Japan to surrender. [67]

Document 85 : Memorandum from Major General Clayton Bissell, Assistant Chief of Staff, G-2, for the Chief of Staff, “Estimate of Japanese Situation for Next 30 Days,” August 12, 1945, Top Secret

Source: National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Not altogether certain that surrender was imminent, Army intelligence did not rule out the possibility that Tokyo would try to “drag out the negotiations” or reject the Byrnes proposal and continue fighting. If the Japanese decided to keep fighting, G-2 opined that “Atomic bombs will not have a decisive effect in the next 30 days.” Richard Frank has pointed out that this and other documents indicate that high level military figures remained unsure as to how close Japan really was to surrender.

Document 86 : The Cabinet Meeting over the Reply to the Four Powers (August 13)

Source:  Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the  kokutai  and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87 : Telephone conversation transcript, General Hull and Colonel Seaman [sic] – 1325 – 13 Aug 45, Top Secret

Source: George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

While Truman had rescinded the order to drop nuclear bombs, the war was not yet over and uncertainty about Japan’s next step motivated war planner General John E. Hull (assistant chief of staff for the War Department’s Operations Division), and one of Groves’ associates, Colonel L. E. Seeman, to continue thinking about further nuclear use and its relationship to a possible invasion of Japan. As Hull explained, “should we not concentrate on targets that will be of greatest assistance to an invasion rather than industry, morale, psychology, etc.” “Nearer the tactical use”, Seaman agreed and they discussed the tactics that could be used for beach landings. In 1991 articles, Barton Bernstein and Marc Gallicchio used this and other evidence to develop the argument that concepts of tactical nuclear weapons use first came to light at the close of World War II. [69]

Document 88 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1236 – August 13, 1945, Top Secret Ultra

The dropping of two atomic bombs, the tremendous destruction caused by U.S. bombing, and the Soviet declaration of war notwithstanding, important elements of the Japanese Army were unwilling to yield, as was evident from intercepted messages dated 12 and 13 August. Willingness to accept even the “destruction of the Army and Navy” rather than surrender inspired the military coup that unfolded and failed during the night of 14 August.

Document 89 : “The Second  Sacred Judgment”, August 14, 1945

Source :   Hiroshi [Kaian) Shimomura, S husenki [Account of the End of the War]  (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak. 

  Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor).  Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS  Missouri , in Tokyo harbor. [71]

Document 90 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 515, August 18, 1945

This summary includes an intercepted account of the destruction of Nagasaki.

Document 91 :Washington Embassy Telegram 5599 to Foreign Office, 14 August 1945, Top Secret [72]

Source: The British National Archives, Records of the Foreign and Commonwealth Office,  FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73]  As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

XI. Confronting the Problem of Radiation Poisoning

Document 92 : P.L. Henshaw and R.R. Coveyou to H.J. Curtis and K. Z. Morgan, “Death from Radiation Burns,” 24 August 1945, Confidential

Source: Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville  News Sentinel  about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma waves), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93 : Memorandum of Telephone Conversation Between General Groves and Lt. Col. Rea, Oak Ridge Hospital, 9:00 a.m., August 28, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b

Despite the reports pouring in from Japan about radiation sickness among the victims of Hiroshima and Nagasaki, General Groves and Dr. Charles Rea, a surgeon who was head of the base hospital at Oak Ridge (and had no specialized knowledge about the biological effects of radiation) dismissed the reports as “propaganda”. Unaware of the findings of Health Division scientists, Groves and Rhea saw the injuries as nothing more than “good thermal burns.” [75]

Documents 94A-B: General Farrell Surveys the Destruction

94A . Cable CAX 51813 from  USS Teton  to Commander in Chief Army Forces Pacific Administration, From Farrell to Groves, September 10, 1945, Secret

94B . Cable CAX 51948 from Commander in Chief Army Forces Pacific Advance Yokohoma Japan to Commander in Chief Army Forces Pacific Administration, September 14, 1945, Secret

Source: RG 77, Tinian Files, April-December 1945, box 17, Envelope B

A month after the attacks Groves’ deputy, General Farrell, traveled to Japan to see for himself the destruction of Hiroshima and Nagasaki. His vivid account shows that senior military officials in the Manhattan Project were no longer dismissive of reports of radiation poisoning. As Farrell observed in his discussion of Hiroshima, “Summaries of Japanese reports previously sent are essentially correct, as to clinical effects from single gamma radiation dose.” Such findings dismayed Groves, who worried that the bomb would fall into a taboo category like chemical weapons, with all the fear and horror surrounding them. Thus, Groves and others would try to suppress findings about radioactive effects, although that was a losing proposition. [76]

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95 : Entry for 4 October 1945, Robert P. Meiklejohn Diary

In this entry written several months later, Meiklejohn shed light on what much later became an element of the controversy over the Hiroshima-Nagasaki bombings: whether any high level civilian or military officials objected to nuclear use. Meiklejohn recounted Harriman’s visit in early October 1945 to the Frankfurt-area residence of General Dwight Eisenhower, who was finishing up his service as Commanding General, U.S. Army, European Theater. It was Meiklejohn’s birthday and during the dinner party, Eisenhower and McCloy had an interesting discussion of atomic weapons, which included comments alluding to scientists’ statements about what appears to be the H-bomb project (a 20 megaton weapon), recollection of the early fear that an atomic detonation could burn up the atmosphere, and the Navy’s reluctance to use its battleships to test atomic weapons. At the beginning of the discussion, Eisenhower made a significant statement: he “mentioned how he had hoped that the war might have ended without our having to use the atomic bomb.” The general implication was that prior to Hiroshima-Nagasaki, he had wanted to avoid using the bomb.

Some may associate this statement with one that Eisenhower later recalled making to Stimson. In his 1948 memoirs (further amplified in his 1963 memoirs), Eisenhower claimed that he had “expressed the hope [to Stimson] that we would never have to use such a thing against an enemy because I disliked seeing the United States take the lead in introducing into war something as horrible and destructive as this new weapon was described to be.” That language may reflect the underlying thinking behind Eisenhower’s statement during the dinner party, but whether Eisenhower used such language when speaking with Stimson has been a matter of controversy. In later years, those who knew both thought it unlikely that the general would have expressed misgivings about using the bomb to a civilian superior. Eisenhower’s son John cast doubts about the memoir statements, although he attested that when the general first learned about the bomb he was downcast.

Stimson’s diary mentions meetings with Eisenhower twice in the weeks before Hiroshima, but without any mention of a dissenting Eisenhower statement (and Stimson’s diaries are quite detailed on atomic matters). The entry from Meiklejohn’s diary does not prove or disprove Eisenhower’s recollection, but it does confirm that he had doubts which he expressed only a few months after the bombings. Whether Eisenhower expressed such reservations prior to Hiroshima will remain a matter of controversy. [77]

Document 96:  President Harry S. Truman, Handwritten Remarks for Gridiron Dinner, circa 15 December 1945 [78]

Source: Harry S. Truman Library,  President's Secretary's Files,  Speech Files, 1945-1953,  copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press.  [79]

In accordance with the dinner’s rules that “reporters are never present,” Truman’s remarks were off-the record. The president, however, wrote in long-hand a text that that might approximate what he said that evening. Pages 12 through 15 of those notes refer to the atomic bombing of Japan:

“You know the most terrible decision a man ever had to make was made by me at Potsdam. It had nothing to do with Russia or Britain or Germany. It was a decision to loose the most terrible of all destructive forces for the wholesale slaughter of human beings. The Secretary of War, Mr. Stimson, and I weighed that decision most prayerfully. But the President had to decide. It occurred to me that a quarter of a million of the flower of our young manhood was worth a couple of Japanese cities, and I still think that they were and are. But I couldn’t help but think of the necessity of blotting out women and children and non-combatants. We gave them fair warning and asked them to quit. We picked a couple of cities where war work was the principle industry, and dropped bombs. Russia hurried in and the war ended.”

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]  

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48].  [81]

Where he had taken significant responsibility was by making a decision to stop the atomic bombings just before the Japanese surrender, thereby asserting presidential control over nuclear weapons

The editor thanks Barton J. Bernstein, J. Samuel Walker, Gar Alperovitz, David Holloway, and Alex Wellerstein for their advice and assistance, and Tsuyoshi Hasegawa for kindly providing copies of some of the Japanese sources that were translated for this compilation. Hasegawa’s book,  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005), includes invaluable information on Japanese sources. David Clark, an archivist at the Harry S. Truman Library, and James Cross, Manuscripts Archivist at Clemson University Library’s Special Collections, kindly provided material from their collections. The editor also thanks Kyle Hammond and Gregory Graves for research assistance and Toshihiro Higuchi and Hikaru Tajima (who then were graduate students in history at Georgetown University and the University of Tokyo respectively), for translating documents and answering questions on the Japanese sources. The editor thanks Anna Melyakova (National Security Archive) for translating Russian language material.

Read the documents

I. background on the u.s. atomic project   documents 1a-c: report of the uranium committee.

Document 1A

National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

Document 1B

See description of document 1A.

Document 1C

Document 2A

RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942)

Document 2B

Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

See description of document 2A.

National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt. Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over 125,000 people ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10] For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

Documents 6A-D: President Truman Learns the Secret

Document 6A

G 77, Commanding General’s file no. 24, tab D

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from briefings by  Secretary of War Stimson and Manhattan Project chief General Groves (who went through the “back door” to escape the watchful press). Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.”

In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize. With respect to the point about assembling the weapons, Groves and Stimson informed Truman that the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.”  

These documents have important implications for the perennial debate over whether Truman “inherited assumptions” from the Roosevelt administration that the bomb would be used when available or that he made  the  decision to do so.  Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s ”decision” amounted to a decision not to override previous plans to use the bomb.” [12]

Document 6B

Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

See description of document 6A.

Document 6C

Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”

Document 6D

RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless. [13] According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction. [16]

Document 10

RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions. [17]

Document 11

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city. [18]

Document 12

Document 13

Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

Document 14

Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly. [21] An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Document 15

Document 16

At the end of May General Groves forwarded to Army Chief of Staff Marshall a “Plan of Operations” for the atomic bombings. While that plan has not surfaced, apparently its major features were incorporated in this 29 May 1945 message on the “special functions” of the 509th Composite Group sent from Chief of Staff General Lauris Norstad to General Curtis LeMay, chief of the XXI Bomber Command, headquartered in the Marianas Islands. [21A] The Norstad message reviewed the complex requirements for preparing B-29s and their crew for delivering nuclear weapons.  He detailed the mission of the specially modified B-29s that comprised the  509th Composite Group, the “tactical factors” that applied,  training and rehearsal issues, and the functions of “special personnel” and the Operational Studies Group.  The targets listed—Hiroshima, Kyoto, and Niigato—were those that had been discussed at the Target Committee meeting on 28 May, but Kyoto would be dropped when Secretary Stimson objected (although that would remain a contested matter) and Kokura would eventually be substituted.   As part of the Composite Group’s training to drop “special bombs,” it would practice with facsimiles—the conventionally-armed “Pumpkins.” The 509th Composite Group’s cover story for its secret mission was the preparation for the use of “Pumpkins” in battle.

Document 17

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]

Document 18

RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project,  problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.”  In his comments on a detonation over Japanese targets, Oppenheimer mentioned that the “neutron effect would be dangerous to life for a radius of at least two-thirds of a mile,” but did not mention that the radiation could cause prolonged sickness.

Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.”  Bernstein argues that this target choice represented an uneasy endorsement of “terror bombing”-the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23] It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19

Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.” [24]

Document 20

Document 21

Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back). [25] As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh. The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

Document 22

RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock. [26]

Document 23

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

Document 24

Document 25

Document 26

Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186th-194th

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated. [29]

Document 27

Document 28

RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Document 29

Document 30

RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Document 31

Document 32

Document 33

Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor. [32]

Document 34

Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

Document 35

RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

Document 36

Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

Document 37

Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor. Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38

IV. The Japanese Search for Soviet Mediation   Documents 39A-B: Magic

Document 39A

National Security Agency Mandatory declassification review release.

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

Document 39B

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Document 40

RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

Document 41

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Document 42

Document 43

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

Document 44

L.D. Riabev, ed., Atomnyi Proekt SSSR (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

Document 45

RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the Trinity Test of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46

RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

Document 47

Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,” Foreign Service Journal, July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

Document 48

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46] During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50

Document 51

Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.” [49]

Document 52

Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

VII. Debates among the Japanese – Late July/Early August 1945

Document 53

In the Potsdam Declaration the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51] Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54

Document 55

Document 56

Document 57

Document 58

RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

Document 59

VIII. The Execution Order   Documents 60A-D: These messages convey the process of creating and transmitting the execution order to bomb Hiroshima. Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam

Document 60A

RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e (copies from microfilm)

These messages convey the process of creating and transmitting the execution order to bomb Hiroshima.  Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55] On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 60B

See description of document 60A.

Document 60C

Document 60D

Document 60E

Document 61

RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56] Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Document 62A

RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

Document 62B

See description of document 62A.

Document 62C

Document 63

RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Document 64

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65

A. Zolotarev, ed., Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody (Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

Document 66

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

Documents 67A-B: Early High-level Reactions to the Hiroshima Bombing

Document 67A

Gaimusho (Ministry of Foreign Affairs) ed. Shusen Shiroku (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day. [59a]

Document 67B

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Document 68

Document 69

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Document 70

W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Document 71

Documents 72A-C: The Attack on Nagasaki

Document 72A

RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

Document 72B

See description of document 72A.

Document 72C

Document 73A

Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

Document 73B

See description of document 73A.

Document 74

Document 75

Zenshiro Hoshina, Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made go-seidan [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the kokutai (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the kokutai narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76

Document 77A

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic.

Document 77B

A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78

Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the Byrnes note .

Document 79

Document 80

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status. The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary. According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82

George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Document 84

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

Document 85

National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Document 86

Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the kokutai and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87

George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

Document 88

Document 89

Hiroshi [Kaian) Shimomura, Shusenki [Account of the End of the War] (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak.

Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor). Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS Missouri , in Tokyo harbor. [71]

Document 90

Document 91

The British National Archives, Records of the Foreign and Commonwealth Office, FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73] As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

Document 92

Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville News Sentinel about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma and neutron radiation), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93

RG 77, MED Records, Top Secret Documents, File no. 5b

Document 94A

RG 77, Tinian Files, April-December 1945, box 17, Envelope B

See description of document 94B

Document 94B

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95

Document 96

Harry S. Truman Library, President's Secretary's Files, Speech Files, 1945-1953, copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press. [79]

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48]. [81]

[1] . The World Wide Web includes significant documentary resources on these events. The Truman Library has published a helpful collection of archival documents , some of which are included in the present collection. A collection of transcribed documents is Gene Dannen’s “ Atomic Bomb: Decision .” For a print collection of documents, see Dennis Merrill ed.,  Documentary History of the Truman Presidency: Volume I: The Decision to Drop the Atomic Bomb on Japan  (University Publications of America, 1995). A more recent collection of documents, along with a bibliography, narrative, and chronology, is Michael Kort’s  The Columbia Guide to Hiroshima and the Bomb  (New York: Columbia University Press, 2007). An important  on-line collection focuses on the air-raids of Japanese cities and bases, providing valuable context for the atomic attacks.

[2] . For the early criticisms and their impact on Stimson and other former officials, see Barton J. Bernstein, “Seizing the Contested Terrain of Early Nuclear History: Stimson, Conant, and Their Allies Explain the Decision to Use the Atomic Bomb,”  Diplomatic History  17 (1993): 35-72, and James Hershberg,  James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 291-301.

For Stimson’s article, see “The Decision to Use the Atomic Bomb,”  Harper’s  194 (February 1947): 97-107. Social critic Dwight MacDonald published trenchant criticisms immediately after Hiroshima-Nagasaki; see  Politics Past: Essays in Political Criticism  (New York: Viking, 1972), 169-180.

[3] . The proposed script for the Smithsonian exhibition can be seen at Philipe Nobile,

Judgment at the Smithsonian  (New York: Matthews and Company, 1995), pp. 1-127. For reviews of the controversy, see Barton J. Bernstein, “The Struggle Over History: Defining the Hiroshima Narrative,” ibid., 128-256, and Charles T. O’Reilly and William A. Rooney,  The Enola Gay and The Smithsonian  (Jefferson, NC: McFarland and Company, 2005).

[4] . For the extensive literature, see the references in J. Samuel Walker , Prompt and Utter Destruction: Truman and the Use of Atomic Bombs against Japan,  Third Edition (Chapel Hill: University of North Carolina Press, 2016) at 131-136, as well as Walker’s, “Recent Literature on Truman’s Atomic Bomb Decision: A Search for Middle Ground,”  Diplomatic History  29 (April 2005): 311-334. For more recent contributions, see Sean Malloy,  Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan  (Ithaca: Cornell University Press, 2008), Andrew Rotter,  Hiroshima: The World's Bomb  (New York: Oxford, 2008), Campbell Craig and Sergey Radchenko,  The Atomic Bomb and the Origins of the Cold War  (New Haven, Yale University Press, 2008), Wilson D. Miscamble,  The Most Controversial Decision: Truman, the Atomic Bombs, and the Defeat of Japan  (New York: Cambridge University Press, 2011). Also important to take into account is John Dower’s extensive discussion of Hiroshima/Nagasaki in context of the U.S. fire-bombings of Japanese cities in  Cultures of War: Pearl Harbor/Hiroshima/9-11/Iraq  (New York, W. Norton, 2010), 163-285.

[5] . The editor particularly benefited from the source material cited in the following works: Robert S. Norris,  Racing for the Bomb: General Leslie S. Groves, The Manhattan Project’s Indispensable Man  (South Royalton, VT: Steerforth Press, 2002); Gar Alperovitz,  The Decision to Use the Bomb and the Architecture of an American Myth  (New York: Alfred E. Knopf, 1995); Richard B. Frank , Downfall: The End of the Imperial Japanese Empire  (New York: Random House, 1999), Martin Sherwin,  A World Destroyed: Hiroshima and the Origins of the Arm Race  (New York, Vintage Books, 1987), and as already mentioned, Hasegawa’s  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005 ).  Barton J. Bernstein’s numerous articles in scholarly publications (many of them are listed in Walker’s assessment of the literature) constitute an invaluable guide to primary sources. An article that Bernstein published in 1995, “The Atomic Bombings Reconsidered,”  Foreign Affairs  74 (1995), 135-152, nicely summarizes his thinking on the key issues.   Noteworthy publications since 2015 include Michael D. Gordin and G. John Ikenberry, eds., The Age of Hiroshim a (Princeton: Princeton University Press, 2019); Sheldon Garon, “On the Transnational Destruction of Cities: What Japan and the United States Learned from the Bombing of Britain and Germany in the Second World War,” Past and Present 247 (2020): 235-271; Katherine E. McKinney, Scott Sagan, and Allen S. Weiner, “Why the Atomic Bombing of Hiroshima Would Be Illegal Today,” The Bulletin of the Atomic Scientist s 76 (2020); Gregg Mitchell, The Beginning or the End: How Hollywood and America Learned  to Stop Worrying and Love the Bomb (New York: The New Press, 2020); Steve Olson, The Apocalypse Factory: Plutonium and the Making of the Atomic Age (New York: W.W. Norton, 2020); Neil J. Sullivan, The Prometheus Bomb: The Manhattan Project and Government in the Dark  (Lincoln, NE: University of Nebraska Press/Potomac Books, 2016); Alex Wellerstein; Restricted Data: The History of Nuclear Secrecy in the United States,  (Chicago: University of Chicago Press, forthcoming, 2020), a memoir by a Hiroshima survivor, Taniguchi Sumitero, The Atomic  Bomb on My Back: A Life Story of Survival and Activism (Montpelier, VT: Rootstock Publishing, 2020), and a collection of interviews, Cynthia C. Kelly, ed., The Manhattan Project: The Birth of the Atomic Bomb in the Words of Its Creators, Eyewitnesses, and Historians (Black Dog & Leventhal, 2020).

[6] . Malloy (2008), 49-50. For more on the Uranium Committee, the decision to establish the S-1 Committee, and the overall context, see James G. Hershberg , James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 140-154.

[7] . Sean Malloy, “`A Very Pleasant Way to Die’: Radiation Effects and the Decision to Use the Atomic Bomb against Japan,”  Diplomatic History  36 (2012), especially 523. For an important study of how contemporary officials and scientists looked at the atomic bomb prior to first use in Japan, see Michael D. Gordin,  Five Days in August: How World War II Became a Nuclear War  (Princeton: Princeton University Press, 2007).

[8] . Norris, 169.

[9] . Malloy (2008), 57-58.

[10] . See also Norris, 362.

[11] . For discussion of the importance of this memorandum, see Sherwin, 126-127, and Hershberg , James B. Conant , 203-207.

[12] . Alperovitz, 662; Bernstein (1995), 139; Norris, 377.

[13] . Quotation and statistics from Thomas R. Searle, “`It Made a Lot of Sense to Kill Skilled Workers’: The Firebombing of Tokyo in March 1945,  The Journal of Military History  55 (2002):103. More statistics and a detailed account of the raid is in Ronald Schaffer,  Wings of Judgment: American Bombing in World War II  (New York: Oxford University Press, 1985), 130-137.

[14] . Searle, “`It Made a Lot of Sense to Kill Skilled Workers,’” 118. For detailed background on the Army Air Force’s incendiary bombing planning, see Schaffer (1985) 107-127. On Stimson, see Schaffer (1985), 179-180 and Malloy (2008), 54. For a useful discussion of the firebombing of Tokyo and the atomic bombings, see Alex Wellerstein, “Tokyo vs. Hiroshima,”  Restricted Data: The Nuclear Secrecy Blog ,  22 September 2014

[15] . See for example, Bernstein (1995), 140-141.

[16] . For useful discussion of this meeting and the other Target Committee meetings, see Norris, 382-386.

[17] . Malloy, “A Very Pleasant Way to Die,” 531-534.

[18] . Schaffer,  Wings of Judgment , 143-146.

[19] . Alperovitz argues that the possibility of atomic diplomacy was central to the thinking of Truman and his advisers, while Bernstein, who argues that Truman’s primary objective was to end the war quickly, suggests that the ability to “cow other nations, notably the Soviet Union” was a “bonus” effect. See Bernstein (1995), 142.

[20] . Alperovitz, 147; Robert James Maddox,  Weapons for Victory: The Hiroshima Decision Fifty Years Later  (Columbia: University of Missouri Press, 1995), 52; Gabiel Kolko,  The Politics of War: The World and United States Foreign Policy, 1943-1945  (New York: Pantheon Books, 1990), 421-422. As Alperovitz notes, the Davies papers include variant diary entries and it is difficult to know which are the most accurate.

[21] . Malloy (2008), 112

[21A] . Vincent Jones, Manhattan: The Army and the Atomic Bomb (Washington, D.C.: U.S. Army Center of Military History, 1985), 529.

[22] . Bernstein (1995), 146. See also Barton J. Bernstein, “Looking Back: Gen. Marshall and the Atomic Bombing of Japanese Cities,” Arms Control Today , November 2015.

[23] . Bernstein (1995), 144. See also Malloy (2008), at 116-117, including the argument that 1) Stimson was deceiving himself by accepting the notion that a “vital war plant …surrounded by workers’ houses” was a legitimate military target, and 2) that Groves was misleading Stimson by withholding the Target Committee’s conclusions that the target would be a city center.

[24] . Walker (2005), 320.

[25] . Frank Costigliola,  France and the United States: The Cold Alliance Since World War II  (New York, Twayne, 1992), 38-39.

[26] . Barton J. Bernstein, Introduction to Helen S. Hawkins et al. editors,  Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control  (Cambridge: MIT Press, 1987), xxx-xxv; Sherwin, 210-215.

[27] . Herbert P. Bix,  Hirohito and the Making of Modern Japan  (New York: HarperCollins Publishers, 2000), 523.

[28] . Walker (2005), 319-320.

[29] . For a review of the debate on casualty estimates, see Walker (2005), 315, 317-318, 321, 323, and 324-325.

[30] . Hasegawa, 105; Alperovitz, 67-72; Forrest Pogue,  George C. Marshall: Statesman, 1945-1959  (New York: Viking, 1987), 18. Pogue only cites the JCS transcript of the meeting; presumably, an interview with a participant was the source of the McCloy quote.

[31] . Alperovitz, 226; Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 237, note 22.

[32] . Malloy (2008), 123-124.

[33] . Alperovitz, 242, 245; Frank, 219.

[34] . Malloy (2008), 125-127.

[35] . Bernstein, introduction,  Toward a Livable World , xxxvii-xxxviii.

[36] . “Magic” summaries for post-August 1945 remain classified at the National Security Agency. Information from the late John Taylor, National Archives. For background on Magic and the “Purple” code, see John Prados,  Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II (  New York: Random House, 1995), 161-172 and David Kahn,  The Codebreakers: The Story of Secret Writing  (New York: Scribner, 1996), 1-67.

[37] . Alperovitz, 232-238.

[38] . Maddox, 83-84; Hasegawa, 126-128. See also Walker (2005), 316-317.

[39] . Hasegawa, 28, 121-122.

[40] . Peter Grose,  Gentleman Spy: The Life of Allen Dulles  (Boston: Houghton Mifflin, 1994), 170-174, 248-249.

[41] . David Holloway, “Barbarossa and the Bomb: Two Cases of Soviet Intelligence in World War II,” in Jonathan Haslam and Karina Urbach, eds.,  Secret Intelligence in the European States System, 1918-1989  (Stanford: Stanford University Press, 2014), 63-64. For the inception of the Soviet nuclear program and the role of espionage in facilitating it, see Holloway,  Stalin and the Bomb  (New Haven, Yale University Press, 1994).

[42] . For the distances, see Norris, 407.

[43] . For on-line resources on the first atomic test .

[44] . Bernstein’s detailed commentary on Truman’s diary has not been reproduced here except for the opening pages where he provides context and background.

[45] . Frank, 258; Bernstein (1995), 147; Walker (2005), 322. See also Alex Wellerstein’s “ The Kyoto Misconception ”

[46] . Maddox, 102; Alperovitz, 269-270; Hasegawa, 152-153.

[47] . Hasegawa, 292.

[48] . Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 146-147; Alperovitz, 415; Frank, 246.

[49] . Alperovitz, 392; Frank, 148.

[50] . Alperovitz, 281-282. For Davies at Potsdam, see Elizabeth Kimball MacLean,  Joseph E. Davies: Envoy to the Soviets  (Westport, CT: Praeger, 1992), 151-166

[51] . Hasegawa, 168; Bix, 518.

[52] . Bix, 490, 521.

[53] . Alperovitz, 415; Frank, 246.

[54] . Frank, 273-274; Bernstein, “The Alarming Japanese Buildup on Southern Kyushu, Growing U.S. Fears and Counterfactual Analysis: Would the Planned November 1945 Invasion of Southern Kyushu Have Occurred?”  Pacific Historical Review  68 (1999): 561-609.

[55] . Maddox, 105.

[56] . Barton J. Bernstein, "'Reconsidering the 'Atomic General': Leslie R. Groves,"  The Journal of Military History  67 (July 2003): 883-920. See also Malloy, “A Very Pleasant Way to Die,” 539-540.

[57] . For casualty figures and the experience of people on the ground, see Frank, 264-268 and 285-286, among many other sources. Drawing on contemporary documents and journals, Masuji Ibuse’s novel  Black Rain  (Tokyo, Kodansha, 1982) provides an unforgettable account of the bombing of Hiroshima and its aftermath. For early U.S. planning to detonate the weapon at a height designed to maximize destruction from mass fires and other effects, see Alex Wellerstein, “ The Height of the Bomb .”

[58] . Sadao Asada, “The Shock of the Atomic Bomb and Japan’s Decision to Surrender: A Reconsideration,”  Pacific Historical Review  67 (1998): 101-148; Bix, 523; Frank, 348; Hasegawa, 298. Bix appears to have moved toward a position close to Hasegawa’s; see Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus  . For emphasis on the “shock” of the atomic bomb, see also Lawrence Freedman and Saki Dockrill, “Hiroshima: A Strategy of Shock,” in Saki Dockrill, ed.,  From Pearl Harbor to Hiroshima : the Second World War in Asia and the Pacific, 1941-1945  (New York, St. Martin’s Press, 1994), 191-214. For more on the debate over Japan’s surrender, see Hasegawa’s important edited book,  The End of the Pacific War: A Reappraisal  (Stanford: Stanford University Press, 2007), with major contributions by Hasegawa, Holloway, Bernstein, and Hatano.

[59] . Melvyn P. Leffler, “Adherence to Agreements: Yalta and the Experiences of the Early Cold War,”  International Security  11 (1986): 107; Holloway, “Barbarossa and the Bomb,” 65.

[59a] . For more on these developments, see Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender: A Reconsideration," 486-488.

[60] . Hasegawa, 191-192.

[61] . Frank, 286-287; Sherwin, 233-237; Bernstein (1995), 150; Maddox, 148.

[62] . The Supreme War Council comprised the prime minister, foreign minister, army and navy ministers, and army and navy chiefs of staff; see Hasegawa, 72 .

[63] . For the maneuverings on August 9 and the role of the  kokutai , see Hasegawa, 3-4, 205-214

[64] . For Truman’s recognition of mass civilian casualties, see also his  letter to Senator Richard Russell, 9 August 1945.

[65] . Hasegawa, 295.

[66] . For “tug of war,” see Hasegawa, 226-227.

[67] . Hasegawa, 228-229, 232.

[68] . Hasegawa, 235-238.

[69] . Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking about Tactical Nuclear Weapons,”  International Security  15 (Spring 1991): 149-173; Marc Gallicchio, “After Nagasaki: General Marshall’s Plans for Tactical Nuclear Weapons in Japan,”  Prologue  23 (Winter 1991): 396-404. Letters from Robert Messer and Gar Alperovitz, with Bernstein’s response, provide insight into some of the interpretative issues. “Correspondence,”  International Security  16 (Winter 1991/1992): 214-221.

[70] . Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus .

[71] . For Hirohito' surrender speech--the actual broadcast and a translation--see  Japan Times , August 2015.

[72] . Cited by Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking About Tactical Nuclear Weapons,”  International Security  15 (1991) at page 167. Thanks to Alex Wellerstein for the suggestion and the archival link.

[73] . For further consideration of Tokyo and more likely targets at the time, see Alex Wellerstein, “Neglected Niigata,”  Restricted Data: The Nuclear Secrecy Blog, 9 October 2015.

[74] . See Malloy, “A Very Pleasant Way to Die,” 541-542.

[75] . For Groves and the problem of radiation sickness, see Norris, 339-441, Bernstein, “Reconsidering the ‘Atomic General’: Leslie R. Groves,”  Journal of Military History  67 (2003), 907-908, and Malloy, “A Very Pleasant Way to Die,” 513-518 and 539-542

[76] . See Janet Farrell Brodie, “Radiation Secrecy and Censorship after Hiroshima and Nagasaki,”  The Journal of Social History  48 (2015): 842-864.

[77] . For Eisenhower’s statements, see  Crusade in Europe  (Garden City: Doubleday, 1948), 443, and  Mandate for Change  (Garden City: Doubleday, 1963), 312-313. Barton J. Bernstein’s 1987 article, “Ike and Hiroshima: Did He Oppose It?”  The Journal of Strategic Studies  10 (1987): 377-389, makes a case against relying on Eisenhower’s memoirs and points to relevant circumstantial evidence. For a slightly different perspective, see Malloy (2007), 138

[78] . Cited in Barton J. Bernstein, “Truman and the A-Bomb: Targeting Noncombatants, Using the Bomb, and His Defending the "Decision,”  The Journal of Military History  62 (1998), at page 559. Thanks to Alex Wellerstein for the suggestion and the archival link.

[79] . “Truman Plays Part of Himself in Skit at Gridiron Dinner,” and “List of Members and Guests at the Gridiron Show,”  The Washington Post , 16 December 1945.

[80] . For varied casualty figures cited by Truman and others after the war, see Walker,  Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan , 101-102.

[81] . See also ibid., 59.

Was It Right?

Most of the debate over the atomic bombing of Japan focuses on the unanswerable question of whether it was necessary. But that skirts the question of its morality.  

I imagine that the persistence of that question irritated Harry Truman above all other things. The atomic bombs that destroyed the cities of Hiroshima and Nagasaki fifty years ago were followed in a matter of days by the complete surrender of the Japanese empire and military forces, with only the barest fig leaf of a condition—an American promise not to molest the Emperor. What more could one ask from an act of war? But the two bombs each killed at least 50,000 people and perhaps as many as 100,000. Numerous attempts have been made to estimate the death toll, counting not only those who died on the first day and over the following week or two but also the thousands who died later of cancers thought to have been caused by radiation. The exact number of dead can never be known, because whole families—indeed, whole districts—were wiped out by the bombs; because the war had created a floating population of refugees throughout Japan; because certain categories of victims, such as conscript workers from Korea, were excluded from estimates by Japanese authorities; and because as time went by, it became harder to know which deaths had indeed been caused by the bombs. However many died, the victims were overwhelming civilians, primarily the old, the young, and women; and all the belligerents formally took the position that the killing of civilians violated both the laws of war and common precepts of humanity. Truman shared this reluctance to be thought a killer of civilians. Two weeks before Hiroshima he wrote of the bomb in his diary, “I have told [the Secretary of War] Mr. Stimson to use it so that military objectives and soldiers and sailors are the target and not women and children.” The first reports on August 6, 1945, accordingly described Hiroshima as a Japanese army base.

This fiction could not stand for long. The huge death toll of ordinary Japanese citizens, combined with the horror of so many deaths by fire, eventually cast a moral shadow over the triumph of ending the war with two bombs. The horror soon began to weigh on the conscience of J. Robert Oppenheimer, the scientific director of the secret research project at Los Alamos, New Mexico, that designed and built the first bombs. Oppenheimer not only had threatened his health with three years of unremitting overwork to build the bombs but also had soberly advised Henry Stimson that no conceivable demonstration of the bomb could have the shattering psychological impact of its actual use. Oppenheimer himself gave an Army officer heading for the Hiroshima raid last minute instructions for proper delivery of the bomb.

Don’t let them bomb through clouds or through an overcast. Got to see the target. No radar bombing; it must be dropped visually. ... Of course, they must not drop it in rain or fog. Don't let them detonate it too high. The figure fixed on is just right. Don't let it go up or the target won’t get as much damage.

These detailed instructions were the result of careful committee work by Oppenheimer and his colleagues. Mist or rain would absorb the heat of the bomb blast and thereby limit the conflagration, which experiments with city bombing in both Germany and Japan had shown to be the principal agent of casualties and destruction. Much thought had also been given to finding the right city. It should be in a valley, to contain the blast; it should be relatively undamaged by conventional air raids, so that there would be no doubt of the bomb's destructive power; an educated citizenry was desired, so that it would understand the enormity of what had happened. The military director of the bomb project, General Leslie Groves, thought the ancient Japanese imperial capital of Kyoto would be ideal, but Stimson had spent a second honeymoon in Kyoto, and was afraid that the Japanese would never forgive or forget its wanton destruction; he flatly refused to leave the city on the target list. Hiroshima and Nagasaki were destroyed instead. On the night of August 6 Oppenheimer was thrilled by the bomb's success. He told an auditorium filled with whistling, cheering, foot-stomping scientists and technicians that he was sorry only that the bomb had not been ready in time for use on Germany. The adrenaline of triumph drained away following the destruction of Nagasaki, on August 9. Oppenheimer, soon offered his resignation and by mid-October had severed his official ties. Some months later he told Truman in the White House, “Mr. President, I have blood on my hands.” Truman was disgusted by this cry-baby attitude. “I told him,” Truman said later, “the blood was on my hands—let me worry about that.” Till the end of his life Truman insisted that he had suffered no agonies of regret over his decision to bomb Hiroshima and Nagasaki, and the pungency of his language suggests that he meant what he said. But it is also true that he ordered a halt to the atomic bombing on August 10, four days before the Japanese Emperor surrendered, and the reason, according to a Cabinet member present at the meeting, was that “he didn’t like the idea of killing ... ‘all those kids.’” Was it right? Harry Truman isn’t the only one to have disliked the question. Historians of the war, of the invention of the atomic bomb, and of its use on Japan have almost universally chosen to skirt the question of whether killing civilians can be morally justified. They ask instead, Was it necessary? Those who say it was necessary argue that a conventional invasion of Japan, scheduled to begin on the southernmost island of Kyushu on November 1, 1945, would have cost the lives of large numbers of Americans and Japanese alike. Much ink has been spilled over just how large these numbers would have been. Truman in later life sometimes said that he had used the atomic bomb to save the lives of half a million or even a million American boys who might have died in an island-by-island battle to the bitter end for the conquest of Japan. Where Truman got those numbers is hard to say. In the spring of 1945, when it was clear that the final stage of the war was at hand, Truman received a letter from former President Herbert Hoover urging him to negotiate an end to the war in order to save the “500,000 to 1 million American lives” that might be lost in an invasion. But the commander of the invasion force, General Douglas MacArthur, predicted nothing on that scale. In a paper prepared for a White House strategy meeting held on June 18, a month before the first atomic bomb was tested, MacArthur estimated that he would suffer about 95,000 casualties in the first ninety days—a third of them deaths. The conflict of estimates is best explained by the fact that they were being used at the time as weapons in a larger argument. Admirals William Leahy and Ernest J. King thought that Japan could be forced to surrender by a combination of bombing and naval blockade. Naturally they inflated the number of casualties that their strategy would avoid. MacArthur and other generals, convinced that the war would have to be won on the ground, may have deliberately guessed low to avoid frightening the President. It was not easy to gauge how the battle would go. From any conventional military perspective, by the summer of 1945 Japan had already lost the war. The Japanese navy mainly rested on the bottom of the ocean; supply lines to the millions of Japanese soldiers in China and other occupied territories had been severed; the Japanese air force was helpless to prevent the almost nightly raids by fleets of B-29 bombers, which had been systematically burning Japanese cities since March; and Japanese petroleum stocks were close to gone. The battleship Yamato , dispatched on a desperate mission to Okinawa in April of 1945, set off without fuel enough to return. But despite this hopeless situation the Japanese military was convinced that a “decisive battle” might inflict so many casualties on Americans coming ashore in Kyushu that Truman would back down and grant important concessions to end the fighting. Japan’s hopes were pinned on “special attack forces,” a euphemism for those engaged in suicide missions, such as kamikaze planes loaded with explosives plunging into American ships, as had been happening since 1944. During the spring and summer of 1945 about 8,000 aircraft, along with one-man submarines and “human torpedoes,” had been prepared for suicide missions, and the entire Japanese population had been exhorted to fight, with bamboo spears if necessary, as “One Hundred Million Bullets of Fire.” Military commanders were so strongly persuaded that honor and even victory might yet be achieved by the “homeland decisive battle” that the peace faction in the Japanese cabinet feared an order to surrender would be disobeyed. The real question is not whether an invasion would have been a ghastly human tragedy, to which the answer is surely yes, but whether Hoover, Leahy, King, and others were right when they said that bombing and blockade would end the war. Here the historians are on firm ground. American cryptanalysts had been reading high-level Japanese diplomatic ciphers and knew that the government in Tokyo was eagerly pressing the Russians for help in obtaining a negotiated peace. The sticking point was narrow: the Allies insisted on unconditional surrender; the Japanese peace faction wanted assurances that the imperial dynasty would remain. Truman knew this at the time. What Truman did not know, but what has been well established by historians since, is that the peace faction in the Japanese cabinet feared the utter physical destruction of the Japanese homeland, the forced removal of the imperial dynasty, and an end to the Japanese state. After the war it was also learned that Emperor Hirohito, a shy and unprepossessing man of forty-four whose first love was marine biology, felt pressed to intervene by his horror at the bombing of Japanese cities. The devastation of Tokyo left by a single night of firebomb raids on March 9–10, 1945, in which 100,000 civilians died, had been clearly visible from the palace grounds for months thereafter. It is further known that the intervention of the Emperor at a special meeting, or gozen kaigin , on the night of August 9–10 made it possible for the government to surrender. The Emperor’s presence at a gozen kaigin is intended to encourage participants to put aside all petty considerations, but at such a meeting, according to tradition, the Emperor does not speak or express any opinion whatever. When the cabinet could not agree on whether to surrender or fight on, the Premier, Kantaro Suzuki, broke all precedent and left the military men speechless when he addressed Hirohito, and said, “With the greatest reverence I must now ask the Emperor to express his wishes.” Of course, this had been arranged by the two men beforehand. Hirohito cited the suffering of his people and concluded, “The time has come when we must bear the unbearable.” After five days of further confusion, in which a military coup was barely averted, the Emperor broadcast a similar message to the nation at large in which he noted that “the enemy has begun to employ a new and most cruel bomb. ... “ Are those historians right who say that the Emperor would have submitted if the atomic bomb had merely been demonstrated in Tokyo Bay, or had never been used at all? Questions employing the word “if” lack rigor, but it is very probable that the use of the atomic bomb only confirmed the Emperor in a decision he had already reached. What distressed him was the destruction of Japanese cities, and every night of good bombing weather brought the obliteration by fire of another city. Hiroshima, Nagasaki, and several other cities had been spared from B-29 raids and therefore offered good atomic-bomb targets. But Truman had no need to use the atomic bomb, and he did not have to invade. General Curtis LeMay had a firm timetable in mind for the 21st Bomber Command; he had told General H. H. (“Hap”) Arnold, the commander in chief of the Army Air Corps, that he expected to destroy all Japanese cities before the end of the fall. Truman need only wait. Steady bombing, the disappearance of one city after another in fire storms, the death of another 100,000 Japanese civilians every week or ten days, would sooner or later have forced the cabinet, the army, and the Emperor to bear the unbearable. Was it right? The bombing of cities in the Second World War was the result of several factors: the desire to strike enemies from afar and thereby avoid the awful trench-war slaughter of 1914–1918; the industrial capacity of the Allies to build great bomber fleets; the ability of German fighters and anti-aircraft to shoot down attacking aircraft that flew by daylight or at low altitudes; the inability of bombers to strike targets accurately from high altitudes; the difficulty of finding all but very large targets (that is, cities) at night; the desire of airmen to prove that air forces were an important military arm; the natural hardening of hearts in wartime; and the relative absence of people willing to ask publicly if bombing civilians was right. “Strategic bombing” got its name between the wars, when it was the subject of much discussion. Stanley Baldwin made a deep impression in the British House of Commons in 1932 when he warned ordinary citizens that bombing would be a conspicuous feature of the next war and that “the bomber will always get through.” This proved to be true, although getting through was not always easy. The Germans soon demonstrated that they could shoot down daytime low-altitude “precision” bombers faster than Britain could build new planes and train new crews. By the second year of the war the British Bomber Command had faced the facts and was flying at night, at high altitudes, to carry out “area bombing.” The second great discovery of the air war was that high-explosive bombs did not do as much damage as fire. Experiments in 1942 on medieval German cities on the Baltic showed that the right approach was high-explosive bombs first, to smash up houses for kindling and break windows for drafts, followed by incendiaries, to set the whole alight. If enough planes attacked a small enough area, they could create a fire storm—a conflagration so intense that it would begin to burn the oxygen in the air, creating hundred-mile-an-hour winds converging on the base of the fire. Hamburg was destroyed in the summer of 1943 in a single night of unspeakable horror that killed perhaps 45,000 Germans. While the British Bomber Command methodically burned Germany under the command of Sir Arthur Harris (called Bomber Harris in the press but Butch—short for “Butcher”—by his own men), the Americans quietly insisted that they would have no part of this slaughter but would instead attack “precision” targets with “pinpoint” bombing. But American confidence was soon eroded by daylight disasters, including the mid-1943 raid on ball-bearing factories in Schweinfurt, in which sixty-three of 230 B-17s were destroyed for only paltry results on the ground. Some Americans continued to criticize British plans for colossal city-busting raids as "baby-killing schemes," but by the end of 1943, discouraged by runs of bad weather and anxious to keep planes in the air, the commander of the American Air Corps authorized bombing “by radar”—that is, attacks on cities, which radar could find through cloud cover. The ferocity of the air war eventually adopted by the United States against Germany was redoubled against Japan, which was even better suited for fire raids, because so much of the housing was of paper and wood, and worse suited for “precision” bombing, because of its awful weather and unpredictable winds at high altitudes. On the night of March 9–10, 1945, General LeMay made a bold experiment: he stripped his B-29s of armament to increase bomb load and flew at low altitudes. As already described, the experiment was a brilliant success. By the time of Hiroshima more than sixty of Japan’s largest cities had been burned, with a death toll in the hundreds of thousands. No nation could long resist destruction on such a scale—a conclusion formally reached by the United States Strategic Bombing Survey in its Summary Report ( Pacific War ): “Japan would have surrendered [by late 1945] even if the atomic bombs had not been dropped, even if Russia had not entered the war [on August 8], and even if no invasion had been planned or contemplated.” Was it right? There is an awkward, evasive cast to the internal official documents of the British and American air war of 1939–1945 that record the shift in targets from factories and power plants and the like toward people in cities. Nowhere was the belief ever baldly confessed that if we killed enough people, they would give up; but that is what was meant by the phrase “morale bombing,” and in the case of Japan it worked. The mayor of Nagasaki recently compared the crime of the destruction of his city to the genocide of the Holocaust, but whereas comparisons—and especially this one—are invidious, how could the killing of 100,000 civilians in a day for a political purpose ever be considered anything but a crime? Fifty years of argument over the crime against Hiroshima and Nagasaki has disguised the fact that the American war against Japan was ended by a larger crime in which the atomic bombings were only a late innovation—the killing of so many civilians that the Emperor and his cabinet eventually found the courage to give up. Americans are still painfully divided over the right words to describe the brutal campaign of terror that ended the war, but it is instructive that those who criticize the atomic bombings most severely have never gone on to condemn all the bombing. In effect, they give themselves permission to condemn one crime (Hiroshima) while enjoying the benefits of another (the conventional bombing that ended the war). Ending the war was not the only result of the bombing. The scale of the attacks and the suffering and destruction they caused also broke the warrior spirit of Japan, bringing to a close a century of uncontrolled militarism. The undisguisable horror of the bombing must also be given credit for the following fifty years in which no atomic bombs were used, and in which there was no major war between great powers. It is this combination of horror and good results that accounts for the American ambivalence about Hiroshima. It is part of the American national gospel that the end never justifies the means, and yet it is undeniable that the end—stopping the war with Japan—was the immediate result of brutal means. Was it right? When I started to write this article, I thought it would be easy enough to find a few suitable sentences for the final paragraph when the time came, but in fact it is not. What I think and what I feel are not quite in harmony. It was the horror of Hiroshima and fear of its repetition on a vastly greater scale which alarmed me when I first began to write about nuclear weapons (often in these pages), fifteen years ago. Now I find I have completed some kind of ghastly circle. Several things explain this. One of them is my inability to see any significant distinction between the destruction of Tokyo and the destruction of Hiroshima. If either is a crime, then surely both are. I was scornful once of Truman’s refusal to admit fully what he was doing; calling Hiroshima an army base seemed a cruel joke. Now I confess sympathy for the man—responsible for the Americans who would have to invade; conscious as well of the Japanese who would die in a battle for the home islands; wielding a weapon of vast power; knowing that Japan had already been brought to the brink of surrender. It was the weapon he had. He did what he thought was right, and the war ended, the killing stopped, Japan was transformed and redeemed, fifty years followed in which this kind of killing was never repeated. It is sadness, not scorn, that I feel now when I think of Truman's telling himself he was not “killing ‘all those kids.’” The bombing was cruel, but it ended a greater, longer cruelty. They say that the fiftieth anniversaries of great events are the last. Soon after that the people who took part in them are all dead, and the young have their own history to think about, and the old questions become academic. It will be a relief to move on.

Documents and Debates: The Decision to Use the Atomic Bomb

On July 16, 1945, the USS Indianapolis slipped away from its moorings on Mare Island, California, headed for the South Pacific. The United States military command so heavily guarded the ship’s mission that not even its Captain, Charles B McVay, III, knew its true nature. Ten days later, the Indianapolis arrived at Tinian Island in the Northern Marianas. The crew unloaded its precious cargo – half the world’s supply of U-235 and all the components necessary to build an atomic bomb. The bomb, nicknamed Little Boy, was assembled on Tinian, loaded onto a bomber named the Enola Gay, and dropped on Hiroshima, Japan, August 6, 1945. The blast immediately killed 80,000 people. Three days later – August 9 – a second bomb devastated Nagasaki, Japan. Pressed by a naval blockade of the home islands, the USSR’s entry into the war against Japan, and the atomic catastrophe’s impact, Japan surrendered on August 14, 1945. The war was over.

Peace came too late for nearly 900 members of the USS Indianapolis’s crew. After delivering the bomb, the ship patrolled the waters near Guam then struck out for the Philippine Islands. On the night of July 30, 1945, a mere four days after dropping its cargo on Tinian, a Japanese submarine put two torpedoes into the ship’s hull, killing 300 crew members instantly – the rest went into the water. A series of wartime snafus prevented word from reaching potential rescuers that the Indianapolis was missing. For three-and-a-half days, survivors trod water, dying from dehydration, saltwater poisoning, and sharks. Only 316 survived – the largest single-ship naval disaster in United States history.

Nearly everything connected to this first wartime use of an atomic bomb seems stranger than fiction – from the weapon’s development to the Indianapolis’s horrific fate. The Indianapolis was in California to repair damage caused by a kamikaze attack of Okinawa in March of 1945, making it the right candidate to deliver the bomb.  At its height, the Manhattan Project, the development effort that created the bomb, employed 125,000 workers, spread across the country from Oak Ridge, Tennessee, to Chicago, Illinois, and Los Alamos, New Mexico. The project cost $2B, a staggering sum in the 1940s. It was so secret, even Vice-President of the United States Harry S. Truman was unaware of its existence when he was sworn in as President following Franklin Roosevelt’s death in April of 1945.

Truman had to get up to speed quickly. He met with other Allied leaders in Potsdam three months after becoming President. While at the conference, scientists in New Mexico successfully tested a live bomb, then notified Truman, who informed USSR premier Joseph Stalin. Truman confided to his diary that the news didn’t seem to surprise Stalin. We now know that Stalin knew about the American progress because he had spies at Los Alamos. Now Truman faced one of the most consequential decisions in American presidential history. Should this new weapon, with its tremendous destructive power, be used in hopes of shortening the war with Japan?

Truman sought advice before making the decision from an Interim Committee, composed of scientists and military leaders, charged with considering the moral, political, and military implications of using the bomb. The Interim Committee recommended to Secretary of War Henry Stimson on June 21 “that the weapon be used against Japan at the earliest opportunity, that it be used without warning, and that it be used on a dual target, namely, a military installation or war plant surrounded by or adjacent to homes or other buildings most susceptible to damage.” (Document A)

The military alternative to using the bomb was an invasion of Japan’s main islands, similar to the D-Day invasion of France in June of 1944. General Douglas MacArthur, Supreme Allied Commander in Asia, told Truman that “sooner or later a decisive ground attack must be made.” Casualty predictions for the planned invasion horrified the new President. Truman went to his grave, insisting that using the atomic bomb, deadly as it was, saved more American and Japanese lives than it cost. (Document B)

The documents in Teaching American History’s Volume II , Chapter 23: The Decision to Use the Atomic Bomb set Truman’s decision in the context of the protracted Pacific War and capture much of the reasoning behind it. Reading the documents, students become vicarious decision-makers critiquing the thinking of critical scientific, military, and political leaders as they consider whether to use the most destructive weapon the world has ever known to end earth’s most catastrophic war.

Documents in this chapter include:

A. The Scientific Panel of the Interim Committee, Recommendations on the Immediate Use of Nuclear Weapons, June 16, 1945 B. Minutes of Meetings held at the White House on Monday, June 18, 1945 C. Proclamation Defining Terms for Japanese Surrender, Potsdam, July 26, 1945 D. President Harry S. Truman, Press Release Alerting the Nation About the Atomic Bomb, August 6, 1945 E. J. R. Oppenheimer to Secretary of War Henry Stimson, August 17, 1945

We have also provided audio recordings of the chapter’s Introduction, Documents, and Study Questions . You’ll find these just beneath the headings for each element of the chapter. These recordings support literacy development for struggling readers and the comprehension of challenging text for all students.

Teaching American History: We the Teachers blog will feature chapters from our two-volume Documents and Debates in American History with their accompanying audio recordings each month until recordings of all 29 chapters are complete. Following today’s post on Volume II, Chapter 23, we turn, on March 9th, to Volume I, Chapter 10: The Market Revolution and (The Myth Of) Free Labor. We invite you to continue following this blog closely, so you will be able to take advantage of the new audio feature as the recordings become available.

Access the resources, documents, and readings here.

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Atomic Bomb History

By: History.com Editors

Updated: November 9, 2022 | Original: September 6, 2017

The atomic bomb and nuclear bombs are powerful weapons that use nuclear reactions as their source of explosive energy. Scientists first developed nuclear weapons technology during World War II. Atomic bombs have been used only twice in war—both times by the United States against Japan at the end of World War II, in Hiroshima and Nagasaki. A period of nuclear proliferation followed that war, and during the Cold War, the United States and the Soviet Union vied for supremacy in a global nuclear arms race.

Nuclear Bombs and Hydrogen Bombs

A discovery by nuclear physicists in a laboratory in Berlin, Germany, in 1938 made the first atomic bomb possible, after Otto Hahn, Lise Meitner and Fritz Strassman discovered nuclear fission.

In nuclear fission, the nucleus of an atom of radioactive material splits into two or more smaller nuclei, which causes a sudden, powerful release of energy. The discovery of nuclear fission opened up the possibility of nuclear technologies, including weapons.

Atomic bombs get their energy from fission reactions. Thermonuclear weapons, or hydrogen bombs, rely on a combination of nuclear fission and nuclear fusion. Nuclear fusion is another type of reaction in which two lighter atoms combine to release energy.

Manhattan Project

On December 28, 1942, President Franklin D. Roosevelt authorized the formation of the Manhattan Project to bring together various scientists and military officials working on nuclear research.

The Manhattan Project was the code name for the American-led effort to develop a functional atomic bomb during World War II . The project was started in response to fears that German scientists had been working on a weapon using nuclear technology since the 1930s.

Who Invented the Atomic Bomb?

Much of the work in the Manhattan Project was performed in Los Alamos, New Mexico , under the direction of theoretical physicist J. Robert Oppenheimer , the “ father of the atomic bomb .”

On July 16, 1945, in a remote desert location near Alamogordo, New Mexico , the first atomic bomb was successfully detonated—the Trinity Test . It created an enormous mushroom cloud some 40,000 feet high and ushered in the Atomic Age.

Watch Historic Footage of Atomic Test Explosions

This footage of two nuclear‑test explosions in Hawaii reveal a destructive power so massive it’s still hard to fathom. | Courtesy of the Department of Energy Nevada Operations Office

How Did Emperor Hirohito Respond to the Atomic Bomb Attacks?

After the devastating bombings at Hiroshima and Nagasaki, the leadership of Japanese Emperor Hirohito was put to the test.

Hiroshima And Nagasaki Bombings

Scientists at Los Alamos had developed two distinct types of atomic bombs by 1945—a uranium-based design called “the Little Boy” and a plutonium-based weapon called “the Fat Man.” (Uranium and plutonium are both radioactive elements.)

While the war in Europe had ended in April, fighting in the Pacific continued between Japanese forces and U.S. troops. In late July, President Harry Truman called for Japan’s surrender with the Potsdam Declaration . The declaration promised “prompt and utter destruction” if Japan did not surrender.

On August 6, 1945, the United States dropped its first atomic bomb from a B-29 bomber plane called the Enola Gay over the city of Hiroshima , Japan. The “Little Boy” exploded with about 13 kilotons of force, leveling five square miles of the city and killing 80,000 people instantly. Tens of thousands more would later die from radiation exposure.

When the Japanese did not immediately surrender, the United States dropped a second atomic bomb three days later on the city of Nagasaki . The “Fat Man” killed an estimated 40,000 people on impact.

Nagasaki had not been the primary target for the second bomb. American bombers initially had targeted the city of Kokura, where Japan had one of its largest munitions plants, but smoke from firebombing raids obscured the sky over Kokura. American planes then turned toward their secondary target, Nagasaki.

Citing the devastating power of “a new and most cruel bomb,” Japanese Emperor Hirohito announced his country’s surrender on August 15—a day that became known as ‘ V-J Day ’—ending World War II.

Museums Still Can’t Agree on How to Talk About the 1945 Atomic Bombing of Japan

The Los Alamos Historical Museum halted a Japanese exhibition on the bombings of Hiroshima and Nagasaki because of a controversy over its message of abolishing nuclear weapons.

“Father of the Atomic Bomb” Was Blacklisted for Opposing H‑Bomb

After leading development of the first atomic bomb, J. Robert Oppenheimer called for controls on nuclear weapons. It cost him his job.

Photos: Hiroshima and Nagasaki, Before and After the Bombs

Before the 1945 atomic blasts, they were thriving cities. In a flash, they became desolate wastelands.

The Cold War

The United States was the only country with nuclear weaponry in the years immediately following World War II. The Soviet Union initially lacked the knowledge and raw materials to build nuclear warheads.

Within just a few years, however, the U.S.S.R. had obtained—through a network of spies engaging in international espionage—blueprints of a fission-style bomb and discovered regional sources of uranium in Eastern Europe. On August 29, 1949, the Soviets tested their first nuclear bomb.

The United States responded by launching a program in 1950 to develop more advanced thermonuclear weapons. The Cold War arms race had begun, and nuclear testing and research became high-profile goals for several countries, especially the United States and the Soviet Union.

Cuban Missile Crisis

Over the next few decades, each world superpower would stockpile tens of thousands of nuclear warheads. Other countries, including Great Britain, France, and China, developed nuclear weapons during this time, too.

To many observers, the world appeared on the brink of nuclear war in October of 1962. The Soviet Union had installed nuclear-armed missiles on Cuba, just 90 miles from U.S. shores. This resulted in a 13-day military and political standoff known as the Cuban Missile Crisis .

President John F. Kennedy enacted a naval blockade around Cuba and made it clear the United States was prepared to use military force if necessary to neutralize the perceived threat.

Disaster was avoided when the United States agreed to an offer made by Soviet leader Nikita Khrushchev to remove the Cuban missiles in exchange for the United States promising not to invade Cuba.

Three Mile Island

Many Americans became concerned about the health and environmental effects of nuclear fallout—the radiation left in the environment after a nuclear blast—in the wake of World War II and after extensive nuclear weapons testing in the Pacific during the 1940s and 1950s.

The antinuclear movement emerged as a social movement in 1961 at the height of the Cold War. During Women Strike for Peace demonstrations on November 1, 1961 co-organized by activist Bella Abzug , roughly 50,000 women marched in 60 cities in the United States to demonstrate against nuclear weapons.

The antinuclear movement captured national attention again in the 1970s and 1980s with high profile protests against nuclear reactors after the Three Mile Island accident—a nuclear meltdown at a Pennsylvania power plant in 1979.

In 1982, a million people marched in New York City protesting nuclear weapons and urging an end to the Cold War nuclear arms race. It was one of the largest political protests in United States history.

Nuclear Non-Proliferation Treaty (NPT)

The United States and Soviet Union took the lead in negotiating an international agreement to halt the further spread of nuclear weapons in 1968.

The Treaty on the Non-Proliferation of Nuclear Weapons (also called the Non-Proliferation Treaty or NPT) went into effect in 1970. It separated the world’s countries into two groups—nuclear weapons states and non-nuclear weapons states.

Nuclear weapons states included the five countries that were known to possess nuclear weapons at the time—the United States, the U.S.S.R., Great Britain, France and China.

According to the treaty, nuclear weapons states agreed not to use nuclear weapons or help non-nuclear states acquire nuclear weapons. They also agreed to gradually reduce their stockpiles of nuclear weapons with the eventual goal of total disarmament. Non-nuclear weapons states agreed not to acquire or develop nuclear weapons.

When the Soviet Union collapsed in the early 1990s, there were still thousands of nuclear weapons scattered across Eastern Europe and Central Asia. Many of the weapons were located in Belarus, Kazakhstan and Ukraine. These weapons were deactivated and returned to Russia.

Illegal Nuclear Weapon States

Some countries wanted the option of developing their own nuclear weapons arsenal and never signed the NPT. India was the first country outside of the NPT to test a nuclear weapon in 1974.

Other non-signatories to the NTP include: Pakistan, Israel and South Sudan. Pakistan has a known nuclear weapons program. Israel is widely believed to possess nuclear weapons, though has never officially confirmed or denied the existence of a nuclear weapons program. South Sudan is not known or believed to possess nuclear weapons.

North Korea

North Korea initially signed the NPT treaty, but announced its withdrawal from the agreement in 2003. Since 2006, North Korea has openly tested nuclear weapons, drawing sanctions from various nations and international bodies.

North Korea tested two long-range intercontinental ballistic missiles in 2017—one reportedly capable of reaching the United States mainland. In September 2017, North Korea claimed it had tested a hydrogen bomb that could fit on top an intercontinental ballistic missile.

Iran, while a signatory of the NPT, has said it has the capability to initiate production of nuclear weapons at short notice.

Pioneering Nuclear Science: The Discovery of Nuclear Fission. International Atomic Energy Agency . The Development and Proliferation of Nuclear Weapons. NobelPrize.org . Here are the facts about North Korea’s nuclear test. NPR .

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National Museum of Nuclear Science & History

Debate over the Bomb: An Annotated Bibliography

• Bombings of Hiroshima and Nagasaki

More than seventy years after the end of World War II, the decision to drop the atomic bombs on Hiroshima and Nagasaki  remains controversial . Historians and the public continue to debate if the bombings were justified, the causes of Japan’s surrender, the casualties that would have resulted if the U.S. had invaded Japan, and more. Some historians, often called “traditionalists,” tend to argue that the bombs were necessary in order to save American lives and prevent an invasion of Japan. Other experts, usually called “revisionists,” claim that the bombs were unnecessary and were dropped for other reasons, such as to intimidate the Soviet Union. Many historians have taken positions between these two poles. These books and articles provide a range of perspectives on the atomic bombings. This is not an exhaustive list, but should illustrate some of the different arguments over the decision to use the bombs.

Bibliography on the Debate over the Bomb

• Alperovitz, Gar.  Atomic Diplomacy: Hiroshima and Potsdam . New York: Simon and Schuster, 1965.

——-.  The Decision to Use the Atomic Bomb and the Architecture of an American Myth . New York: Knopf, 1995.

Alperovitz, a prominent revisionist historian, argues that the bombs were unnecessary to force Japan’s surrender. In particular, he posits that the Japanese were already close to surrender and that bombs were primarily intended as a political and diplomatic weapon against the Soviet Union.

• Bernstein, Barton. “Understanding the Atomic Bomb and the Japanese Surrender: Missed Opportunities, Little-Known Near Disasters, and Modern Memory.”  Diplomatic History  19 (Spring 1995): 227-73.

Bernstein challenges the notions that the Japanese were ready to surrender before Hiroshima and that the atomic bombings were primarily intended to intimidate the Soviet Union. He also questions traditionalist claims that the U.S. faced a choice between dropping the bomb and an invasion, and that an invasion would lead to hundreds of thousands of American casualties.

• Bird, Kai, and Lawrence Lifschultz, eds.  Hiroshima’s Shadow: Writings on the Denial of History and the Smithsonian Controversy . Stony Creek, CT: Pamphleteer’s Press, 1998.

This collection of essays and primary source documents, written primarily from a revisionist perspective, provides numerous critiques of the use of the atomic bombs. It includes a foreword by physicist  Joseph Rotblat , who left the Manhattan Project in 1944 on grounds of conscience.

• Bix, Herbert P.  Hirohito and the Making of Modern Japan . New York: Perennial, 2000.

This Pulitzer Prize-winning biography of the Japanese emperor asserts that the Japanese did not decide to surrender until after the bombings and the Soviet invasion of Manchuria. Bix attributes responsibility for the bombings to Hirohito’s “power, authority, and stubborn personality” and President Truman’s “power, determination, and truculence.”

• Craig, Campbell and Radchenko, Sergey.  The Atomic Bomb and the Origins of the Cold War .  New Haven, CT: Yale University Press, 2008.

A provocative study of the entrance of the atomic bomb onto the global stage. It questions the various influences impacting the United States’ decision to drop the bomb, and discusses the Manhattan Project’s role in orchestrating the bipolar conflict of the Cold War.

• Dower, John W.  Cultures of War: Pearl Harbor/Hiroshima/9-11/Iraq . New York: W. W. Norton, 2010.

Dower states that the U.S. used the bombs in order to end the war and save American lives, but asserts that Truman could have waited a few weeks before dropping the bombs to see if the Soviet invasion of Manchuria would compel Japan to surrender. He argues that Truman employed “power politics” in order to keep the Soviet Union in check, and criticizes both Japanese and American leaders for their inability to make peace.

• Feis, Herbert.  Between War and Peace: The Potsdam Conference . Princeton, NJ: Princton University Press, 1960.

Feis presents a blow-by-blow account of the proceedings at the Potsdam Conference that sought to plan the postwar world. He gives particular attention to the discussion of atomic weapons that took place at the conference, noting how it impacted the negotiations of Harry Truman and the American delegation.

• Frank, Richard B.  Downfall: The End of the Imperial Japanese Empire . New York: Penguin Books, 1999.

Frank contends that the Japanese were not close to surrendering before the bombing of Hiroshima. He also concludes that 33,000-39,000 American soldiers would have been killed in an invasion, much lower than the figures usually given by traditionalists.

• Fussell, Paul.  Thank God for the Atom Bomb and Other Essays . New York: Summit Books, 1988.

In the title essay, Fussell, a World War II veteran, vividly recalls the war’s brutality and defends the bombings as a tragic necessity.

• Giangreco, D.M.  Hell to Pay: Operation Downfall and the Invasion of Japan, 1945-1947 . Annapolis, MD: Naval Institute Press, 2009.

Giangreco defends estimates that an invasion of Japan would have cost hundreds of thousands of American lives, and challenges the argument that using the bombs was unjustified.

• Gordin, Michael D.  Five Days in August: How World War II Became a Nuclear War . Princeton, NJ: Princeton University Press, 2007.

Gordin argues that Hiroshima and Nagasaki stemmed from American decisionmakers’ belief that the bombs were merely an especially powerful conventional weapon. He claims U.S. leaders did not “clearly understand the atomic bomb’s revolutionary strategic potential.”

• Ham, Paul.  Hiroshima Nagasaki: The Real Story of the Atomic Bombings and Their Aftermath . Basingstoke, UK: Picador, 2015.

Ham demonstrates that misunderstandings and nationalist fury from both Allied and Axis powers led to the use of the atomic bombs. Ham also gives powerful witness to its destruction through the eyes of eighty survivors, from twelve-year-olds forced to work in war factories to wives and children who faced the holocaust alone.

• Hasegawa, Tsuyoshi.  Racing the Enemy: Stalin, Truman and the Surrender of Japan . Cambridge: Belknap Press of Harvard University Press, 2005.

In this history of the end of World War II from American, Japanese, and Soviet perspectives, Hasegawa determines that the Soviet invasion of Manchuria was the primary factor in compelling the Japanese to surrender.

• Hersey, John.  Hiroshima . New York: Alfred A. Knopf, 1946.

Hersey’s book-length article, which appeared in the  New Yorker  one year after the bombing of Hiroshima, profiles six survivors of the attack. It helped give the American public a new picture of the human impact of the bomb and brought about a groundswell of negative opinion against nuclear weapons.

• Lifton, Robert Jay, and Greg Mitchell.  Hiroshima in America: A Half Century of Denial . New York: Avon Books, 1995.

Written from a revisionist perspective, this book assesses President Truman’s motivations for authorizing the atomic bombings and traces the effects of the bombings on American society.

• Maddox, Robert James.  Weapons for Victory: The Hiroshima Decision Fifty Years Later . Columbia, MO: University of Missouri Press, 1995.

This analysis contends that Japan had not decided to surrender before Hiroshima, states that the U.S. did not believe the Soviet invasion would force Japan to surrender, and challenges the idea that American officials greatly exaggerated the costs of a U.S. invasion of mainland Japan.

• Malloy, Sean.  Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan .  Ithaca, NY: Cornell University Press, 2008. 

Traces the U.S. government’s decision to drop the atomic bombs on Japan, using the life of Secretary of War Henry L. Stimson as a lens. This biography frames the contested decision as a moral question faced by American policy makers. 

• Miscamble, Wilson D.  The Most Controversial Decision: Truman, the Atomic Bombs, and the Defeat of Japan . New York: Cambridge University Press, 2011.

In this short history, Miscamble critiques various revisionist arguments and posits that the bomb was militarily necessary. He also discusses whether the bombings of Hiroshima and Nagasaki were morally justified.

• Newman, Robert P.  Truman and the Hiroshima Cult . East Lansing, MI: Michigan State University Press, 1995.

Newman argues that Truman made a legitimate military decision to bring the war to an end as quickly as possible. He claims the bombings ultimately saved lives and assails what he calls a “cult” of victimhood surrounding the attacks.

• Rotter, Andrew J.  Hiroshima: The World’s Bomb . Oxford: Oxford University Press, 2008.

This international history of the race to develop the bomb asserts that Truman was primarily motivated by a desire to end the war as quickly as possible, with a minimal loss of American lives. Rotter states that the shocks caused by the atomic bombings and the Soviet invasion of Manchuria were both pivotal to Japan’s surrender.

• Stimson, Henry L. “ The Decision to Use the Atomic Bomb .”  Harper’s Magazine  194:1167 (February 1947): 97-107.

Writing a year and a half after Hiroshima and Nagasaki, former Secretary of War Stimson defends the U.S. decision. He documents the refusal of the Japanese to surrender and estimates that an Allied invasion would have resulted in one million American casualties and many more Japanese deaths.

• Walker, J. Samuel.  Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan . Chapel Hill: University of North Carolina Press, 2004.

In a concise critique of both traditionalist and revisionist interpretations of Truman’s decision, Walker concludes that the primary motivation for the use of the bombs was to end World War II as quickly as possible.

• Zeiler, Thomas W.  Unconditional Defeat: Japan, America, and the End of World War II . Wilmington, DE: Rowman & Littlefield, 2003.

This history chronicles the brutality of the fighting between the U.S. and Japan in the Pacific. Zeiler concludes that the bombings of Hiroshima and Nagasaki were mostly motivated by military, rather than political, reasons.  

If you have suggestions for resources that should be listed here, please  contact us .

Truman announces Japanese surrender.

Hiroshima Atomic Dome Memorial. Photo by Dmitrij Rodionov, Wikimedia Commons.

Nagasaki, October 1945

Paul Tibbets and the Enola Gay. Courtesy of the Joseph Papalia Collection.

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Was Truman's Decision to Drop the Bomb, To End the War in the Pacific, Justified or Not?

• Students will watch videos, view photographs, read primary documents, and write a consenting or dissenting view through a persuasive essay.  They will then participate in an open debate through a practice called, “Tag you are it.” Cross-curricular participation could occur with the English teacher who will grade their essay and the Speech teacher who will grade their debate participation.
• Introduction:  Over the last 50 years tremendous controversy has arisen over the United States and President Harry S. Truman’s decision to use and drop the bomb on the Japanese cities of Hiroshima and Nagasaki in August 1945. It is important to remember, that the final, ultimate decision rested solely in the hands of our Commander-in-Chief, President Truman. Both points of conflicting view argue over the necessity of ending the war, just in differing ways, of course, the main difference being the more than 200,000 civilians who died. The documents and videos chosen for this topic are ones describing the arguments for or against the decision to drop the bomb.

It is imperative for students to develop their own cognitive understanding through their own reasoning (which can be developed thoroughly through their own research, utilizing primary and secondary sources). By allowing students to research, synthesis and analysis actual sources from an event, such as the US decision to drop the bomb, they can then, on their own, better rationalize the past and apply it to their own present and future. Therefore, students will analysis and evaluate primary documents, videos, excerpts from newspapers and books, and then in groups will create a persuasive essay supporting their point of view, including quotations from the provided sources, AND debate their point of view.

• Learn to write a persuasive point of view in essay form, consenting or dissenting, the dropping of the bomb to end the War in the Pacific, including quotes from provided sources (ALTHOUGH students are welcome to do research on their own; if they do, they need to cite all sources correctly). 
•  Develop a deeper understanding of what led up to the utilization of the bomb by the US through research and document analysis. They will look at documents through a historical perspective (who wrote the document, when, where, why; is it reliable, why or why not). Develop a deeper understanding of the controversy of President Truman’s decision to drop the bomb on Japan to end the War in the Pacific.
• Contextualize and corroborate with the other students within their group over the documents, photographs, and videos provided, comparing and contrasting points of view, creating a Thesis Statement. 
• Use their prior knowledge of history to write, including their own view of the moral implications of the decision to drop the bomb and whether it was or was not justified through their evaluating the documents, videos, and pictures provided, reflecting their analysis through their writing.
• 7. Knowledge of the use of tools of social science inquiry (such as surveys, statistics, maps and documents)

           C. Understanding fact, opinion, bias and points of view in sources - Distinguish between fact and opinion and recognize bias and points of view

           G. Supporting a point of view - Identify, research and defend a point of view/position

COMMON CORE STANDARDS FOR GRADE 8:

Key Ideas and Details:

• CCSS.ELA-LITERACY.RH.6-8.1 Cite specific textual evidence to support analysis of primary and secondary sources.
• CCSS.ELA-LITERACY.RH.6-8.2 Determine the central ideas or information of a primary or secondary source; provide an accurate summary of the source distinct from prior knowledge or opinions.

Integration of Knowledge and Ideas:

• CCSS.ELA-LITERACY.RH.6-8.7 Integrate visual information (e.g., in charts, graphs, photographs, videos, or maps) with other information in print and digital texts.
• CCSS.ELA-LITERACY.RH.6-8.8 Distinguish among fact, opinion, and reasoned judgment in a text.
• Document 1:

Harry S. Truman. Memoirs. Garden City, New York: Doubleday, 1955. Pages 419-423.

• Documents 2 and 3:

Frank, Richard B. “Downfall, the end of the Imperial Japanese Empire.” Penguin Group, New York, NY, 1999. Pages 248, 269.

• Document 4:

www.getty.edu/education/teachers/timeline

      Video about the Manhattan project

      https://www.britannica.com/video/223010/did-you-know-Manhattan-Project

      President Truman video reading his announcement to drop the bomb:  https://www.youtube.com/watch?v=e3Ib4wTq0jY

Video Three:

      This is video about HST giving ultimatum to Japan: https://www.youtube.com/watch?v=LIOqL86jfg4

• DOCUMENT 8: This is the picture of the three leaders with FDR, not Truman at Tehran: http://www.americaslibrary.gov/jb/wwii/jb_wwii_stalin_1_e.html
• DOCUMENT 5: This is the Elsey 59 page Document Papers  describing their findings from Japanese interviews:  https://catalog.archives.gov/id/301668424
• DOCUMENT 6: This document is an excerpt from a Japanese newsletter:  Nippon Times (Tokyo), August 10, 1945, adopted from http://www.teachablemoment.org/high/dbq3.html

"I had then set up a committee of top men and had asked them to study with great care the implications the new weapons might have for us. It was their recommendation that the bomb be used against the enemy as soon as it could be done. They recommended further that it should be used without specific warning... I had realized, of course, that an atomic bomb explosion would inflict damage and casualties beyond imagination. On the other hand, the scientific advisors of the committee reported... that no technical demonstration they might propose, such as over a deserted island, would be likely to bring the war to an end. It had to be used against an enemy target. The final decision of where and when to use the atomic bomb was up to me. Let there be no mistake about it. I regarded the bomb as a military weapon and never doubted it should be used."

—President Harry S. Truman

From Harry S. Truman. Memoirs. Garden City, New York: Doubleday, 1955. 419-423. 

Document One Question One:  Why did President Truman feel that the atomic bomb had to be used against enemy targets?

Secretary of Navy, James Forrestal, wrote on July 24, “the cabinet’s…..final judgment and decision was that the war must be fought with all the vigor and bitterness of which the nation was capable so long as the only alternative was the unconditional surrender.”

Question: What position within the cabinet did he hold? What was his opinion on whether Japan would surrender or continue to fight?

Document Three (This also is shown on video TWO)

From Book page 269 Truman’s radio statement on August 6 announcing use of bomb on Hiroshima:

“We are no prepared to obliterate rapidly and completely every productive enterprise the Japanese have above ground in any city.  We shall destroy their docks, their factories and their communications. Let there be no mistake, we shall completely destroy Japan’s power to make war. It was to spare the Japanese from utter destruction that the ultimatum of July 26 was issued at Potsdam.  Their leaders promptly rejected that ultimatum. If they do not now accept our terms they may expect a rain of ruin from the air, the like of which has never been seen on earth.”

Document Three Question One: Had Truman tried to peacefully negotiate with Japan, explain.  What primary targets was Truman prepared to destroy of Japan’s? ­­­­­­

Document Three Question Two:  Why did President Truman feel that the atomic bomb had to be used against enemy targets?

These are key dates in the construction of the atomic bomb and the bombing of Nagasaki:

Albert Einstein writes to President Franklin Roosevelt concerning the use of uranium as a new source of energy leading to creation of new, extremely powerful bombs. He also notes that the German government had stopped the sale of all uranium from Czechoslovakian mines. In slow response, Roosevelt forms a special committee to consider the military implications of atomic research.

September 1 — War begins in Europe.

December 6 — Roosevelt authorizes the Manhattan Engineering District for the purpose of creating an atomic bomb. This would later be called the “Manhattan Project.”

December 7 — The Japanese attack Pearl Harbor.

June — J. Robert Oppenheimer is appointed director of the Manhattan Project.

December 2 — Enrico Fermi’s experiments lead to the first controlled nuclear chain reaction on a squash court beneath Stagg Field at the University of Chicago.

Oppenheimer and the bomb development team are moved to a secret laboratory located at Los Alamos, New Mexico.

July 16 — The first test of the “gadget,” a plutonium bomb, at Trinity Site, White Sands Missile Range, just north of Alamogordo, New Mexico.

August 6 — Hiroshima is bombed. At 9:04 on the morning of August 6, 1945, the Enola Gay dropped the 8,900-pound atomic weapon named  "Little Boy" on Hiroshima, leveling almost 90% of the city.

August 9 — Nagasaki is bombed.

August 14 — Japan announces its surrender followed by a formal surrender in Tokyo Bay on September 2.

The Soviet Union detonates its first atomic device, ending America’s nuclear monopoly.

Document Four Question One:  Why do you think FDR was slow to respond to Einstein’s informative letter about the use of a uranium bomb?

Document Four Question Two: Who was Oppenheimer (can you remember what role he plays in the Truman administration from previous knowledge)?

Document Four Question Three: What was the “gadget?” Why do you think it was called that? What was the bomb dropped on Hiroshima called? Give your inference as to why those nicknames were used (pulling from previous knowledge)?

Document Four Question Four: Why do you think it took Japan almost five days to announce they were truly surrendering?  Why do you think it take almost three weeks for the formal surrender?

Document Five

United States Strategic Bombing Survey: Japan’s Struggle to End the War, July 1, 1946, Harry S. Truman Administration, Elsey Papers.

https://www.trumanlibrary.gov/library/research-files/united-states-strategic-bombing-survey-japans-struggle-end-war

Look at page 50 of the 59 page document, at the second and third paragraphs.

Document Five Question One:  What did the Elsey Papers say was the real reason was the war ended in Japan?

Document Five Question Two:  Who was interviewed, according to these two paragraphs, to give evidence whether the Japanese would have surrendered without the use of the bomb?

Document Five Question Three: According to those witnesses, Japan would have surrendered even WITHOUT what three things occurring?

This is a small section of an article in a Japanese paper the day after the bomb dropped on Nagasaki, truly revealing the author’s negative opinion of the lack of the sanctity of the human life in Japan by the US.

"How can a human being with any claim to a sense of moral responsibility deliberately let loose an instrument of destruction which can at one stroke annihilate an appalling segment of mankind? This is not war: this is not even murder; this is pure nihilism. This is a crime against God and humanity which strikes at the very basis of moral existence. What meaning is there in any international law, in any rule of human conduct, in any concept of right and wrong, if the very foundations of morality are to be overthrown as the use of this instrument of total destruction threatens to do?"

Nippon Times (Tokyo), August 10,1945

Document Six Question One: What words does the author pin, revealing his disgust?

DOCUMENTS SEVEN AND EIGHT: Show students the pictures of the leaders of the US, USSR, and Churchill and ask students to make comparisons, looking carefully at the small details.

DOCUMENT NINE: Students will read Truman’s personal diary entry about his meeting with Stalin.

DOCUMENT NINE QUESTION ONE:  What was Truman’s opinion on his meeting with Stalin? 

DOCUMENT NINE QUESTION TWO:  Did Truman tell Stalin about the bomb and why or why not? Why was this important?

DOCUMENT TEN: This is Truman’s Diary entry on July 25, 1945, describing the bomb testing and how it will be used.

DOCUMENT TEN QUESTION ONE: Truman describes “13 lbs. of the explosives” destroyed what? What inference can you make in the message was he trying to convey? What was Truman hoping to only boom in Japan?

DOCUMENT TEN QUESTION TWO: Who did he have come into his office, mid-morning to discuss the “tactical and political” situation? What was Truman’s opinion of that person? 

Question: what was truly bothering Truman about the continuing of the war?

Question:  what did Truman learn about, called the “Manhattan Project,” and what was his dilemma?  What was his decision? 

Question:  What was the Potsdam Ultimatum?

Question: What did President Truman ask Japan to do after the first bomb was dropped?  Did they?

Question:  What does the word capitulated mean?

Question:  Why did the US drop a second bomb, according to Truman?

Question:  What did Truman urge Japanese people to leave and why?

Question:  What reasons did Truman give, justifying the use of the bomb (give at least two)?

Question: What were many Japanese soldiers training to become?

Question:  Who trained in Japan, to fight against the American?

Question: Who was George Elsey?

Question: What was the purpose/reason for PM Suzuki doing/saying nothing?

Opening Activity – Give students a notecard and ask them to write their opinion right now, without talking to the question on the notecard, then put their name on the card and turn it in.  The question on the card is, “Did the US have justification in dropping the Atomic Bomb on Japan to end the War in the Pacific?” Please write yes or no AND a brief explanation.  We will compare what you wrote when we finish this unit AND see if your opinion has changed OR if you believe the same however, for different reasons.

Activity Two – give out written directions on what your expectations for the students are, along with a rubric.  Explain as students read what they will be evaluating, collaborating on, writing, and debating.

Explain to the students they will be working in two groups (I often assign the groups).  Each group will first be given a set of documents, photographs, and videos to read, look at, and watch (we have classroom computers so students can view the videos at different times and we do not need to watch all together ALTHOUGH that would also work. The rest of day one will be spent within the groups, reading through and deciding which resources they would like to use.

Opening Activity – I would go over photographs of the after effects of the bomb as an entire class – you could have several which are projected in front of the students as they come in ALONG with pictures of Pearl Harbor.  Ask students to quietly observe the photos as they are rotated on the screen and be prepared to discuss briefly how the photos make them feel and why (encourage students to be persuasive in what they reply, aiding their final product – the persuasive essay).

Activity Two – allow students to continue to work in their groups, writing down points to support your point of view, including actual quotes from the sources (you could actually utilize the primary source worksheets on the Truman Library website at /psource.htm ).  I have found these are extremely useful in enabling students to research, even in small details.

Activity Three – students should be working on their group persuasive essay/debate notes so they are ready to debate on Day Three. 

Homework for Day one and Day two should be to work on their own essay/part in the debate.

Opening Activity – Have the room divided into two sides, chairs facing each other.  In the middle of the room will be four chairs facing each other with two chairs behind each.  Half of the chairs will be for those with consenting view points and half will be for those with dissenting points of view.  Explain to students they will be given five minutes to organize/regroup and the debate will start.

Activity One - My students participate in debating often so they understand the rules of conduct, however, you may want to create some rules to go over with them. This is a way to debate my 8th graders truly like because EVERYONE has a role and EVERYONE must participate.  Usually, each team starts out with at least one strong debater in one of their two chairs.  One the debate starts and each side gives an opening statement, the floor is open to only the four students to talk, once one of them is ready to tag out they can ask someone to tag them from the 8 chairs (OR one of the students in the 8 chairs can tag one of the inner circle of 4 so they can rotate positions).  REMEMBER, only the inner circle of 4 students can talk.  This is very active, vocal, and my students love it!  As an instructor, I can see who is truly prepared and who isn’t, even my quiet students actively become involved when they hear from the beginning they HAVE to participate.  I usually allow the debate to continue for 15 minutes, remembering, if there are more than 16 students you need, to stop and rotate students.   

Activity Two – regroup and allow students to offer 4-5 comments over what they learned from each other, merely guiding the conversation. At this point, hand back the notecard from the first day and ask students if anyone’s opinion changed; why or why not? This discussion should take 10-15 minutes.

Homework – ask students to now, rethink their persuasive essay, work on it/finish it and be ready to turn it in the next school day.  

• Students will be graded in their American History Class in three areas, class participation/research, debate participation, and their written essay. 

Rubric below is for Essay:

• Rubric below is for the Debate

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Among historians, I am most well known for my work on the history of the decision to use the atomic bomb on Hiroshima and Nagasaki.

This work began with my 1965 book, Atomic diplomacy: Hiroshima and Potsdam : the use of the atomic bomb and the American confrontation with Soviet power , in which I argued that the then available evidence available pointed to three major conclusions: first, that the first use of these terrible weapons was unnecessary; second, that this was understood by decision makers at the time; and third that there was very substantial though not absolutely definitive evidence that by the late summer of 1945 the decision was primarily influenced by diplomatic considerations related to the Soviet Union.

I revisited this thesis in light of a vastly expanded corpus of evidence in my 1995 book, The Decision to Use the Atomic Bomb and the Architecture of an American Myth . The primary focus of the first book was the complicated way in which the atomic bomb altered and hardened the course of U.S. diplomatic strategy towards the Soviet Union in 1945. The 1995 book focused directly and explicitly on the decision itself. The new book also reviewed the many ways in which myths concerning its use were actively promoted by official and unofficial efforts in the early Cold War years.

A useful account of the debates in the historical profession which erupted in the wake of the publication of The Decision to Use the Atomic Bomb is provided by Doug Long’s archive of the relevant postings from h-net.org.

The books have been published in many languages, including German, Japanese, Korean, Italian, Swedish, Portuguese, and Russian. They have also been the subject of television documentaries in Germany, Japan, the United Kingdom, as well as one of the major themes taken up in an ABC production in the United States.

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Manhattan Project National Historical Park

Essential Question 

Was dropping the atomic bombs on Hiroshima and Nagasaki a necessary use of force to end World War II? 

• Analyze primary and secondary sources to form a claim.  
• Detect useful pieces of text evidence.  
• Explain evidence and reasons with a clear line of reasoning. 
• Orally defend a position amongst a group of peers. 
• Recall and describe information from multiple sources. 

Background 

World War II officially began on September 1, 1939, when Nazi Germany invaded Poland. Soon countries from around the world were fighting the largest war the world has ever seen. There were two main groups of countries that fought in World War II: the Allied Powers and the Axis Powers. The United States (US) joined the Allied Powers after Pearl Harbor, Hawaii was attacked by Japan, an Axis Power, on December 7, 1941. These two groups were fighting the war on two main fronts referred to as the Pacific Theater and the European Theater. The European Theater included countries in northern Africa and western Asia. 

If they wanted to win the war, the US decided they had to create better weapons, and they were going to have to beat Nazi Germany in the race to create the atomic bomb. US Military leaders hired well known and highly skilled scientists and engineers to develop the new weapons. Many of them were refugees from the war or had fled Nazi Germany prior to the war to avoid persecution by the Nazi government. The government established this as a top-secret project so that these devices could be made without the Axis countries, especially Nazi Germany, knowing. The first secret headquarters for this project was in a skyscraper hidden in plain sight in the heart of Manhattan in New York City, hence the name “Manhattan Project.” Once the project leaders realized they needed thousands of workers and large areas of land to be successful, they created three “secret cities” in, Hanford Washington, Los Alamos New Mexico, and Oak Ridge Tennessee. There were many other secret sites located throughout the US and even a few in Canada, but none were as large as the three “secret cities” of Hanford, Los Alamos, and Oak Ridge. 

World War II in Europe ended when Germany surrendered to the Allies on May 2, 1945, but Germany’s Axis ally Japan did not surrender, and war continued in the Pacific Theater. US President Harry S. Truman gave the order to drop Little Boy atomic bomb over Hiroshima, Japan, on August 6, 1945 and then demanded the unconditional surrender of Japan. Japan answered with only silence, refusing to surrender. Three days later, on August 9, 1945, the U.S. dropped a second atomic bomb, Fat Man, over Nagasaki, Japan. On September 2, 1945, Emperor Hirohito and the Japanese government surrendered to the Allies, ending World War II. 

While the Manhattan Project was a wartime effort during World War II, it has had lasting impacts and the entire world is affected by the advent of nuclear science. The use of atomic weapons in the last days of the war launched the nuclear age and the many scientific developments during the Manhattan Project led to significant changes and evolutions in science and technology. Nuclear energy provides electricity for millions of people and nuclear medicine has created major advancements in health care and life-saving technology for many ailments, including cancer. 

On the other hand, when the US dropped two atomic bombs on Japan in the waning days of World War II, tens of thousands of people, mostly civilians, lost their lives, and many who survived suffered lifelong health impacts. Further, the environment in and around Hiroshima and Nagasaki endured significant radioactive contamination. The Manhattan Project also started a “Cold War” and a nuclear arms race that resulted in the development of thousands of nuclear weapons throughout the world and it created environmental damage that will impact the earth for tens of thousands of years. In the development of the “secret cities” the Manhattan Project displaced people from their land, many of which were traditional homelands where their ancestors had lived and worked the land for thousands of years. Tens of thousands of people who moved to the secret cities to work on the Manhattan Project were people of color and the Manhattan Project would not have been possible without them. Yet, they were segregated from their white co-workers and required to live in terrible housing conditions, and many were not allowed to bring their children, nor could they live with their spouse. Most of them were only granted access to low paying jobs, often with no opportunity for promotion, and their work on the Manhattan Project is not well recognized. 

Manhattan Project National Historical Park is tasked with researching and learning about these stories and presenting them to the public in a genuine manner that talks about how the Manhattan Project impacted people, politics, history, science, technology, the environment, human health, and the modern world.

Preparation 

Prepare supplies and digital technology.   

• Print the  Gallery Walk Visuals for the gallery walk and display them around the classroom, the hallway, the cafeteria etc. This lesson works well when students can spread out. Alternatively, they could display each one at laptop stations that students travel through. Or documents can be uploaded to a common interface and students can work alone from their seats.  
• Print Student T-Chart Worksheet .  
• Have the Teacher Example T-Chart available. 
• Print Student Webquest Worksheet .   
• Print Research Organizer .

Lesson Hook/Preview 

Gallery walk:  .

• Students will complete a gallery walk around the classroom, viewing different texts/visuals that relate to the atomic bombings.
• As students walk around, they will fill out the  Student T-Chart Worksheet . The left side is “What do you see, what do you notice?” For example, students might notice who the author is, describe the picture they are seeing, or write down an interesting quote. The right side is “What could it mean? What does it show?” For example, students might explain the meaning of a quote, or provide deeper thoughts on the photo.   
• Before students begin the gallery walk the teacher may model how to complete one row of the T-Chart (see Teacher Example T-Chart ).  
• After the gallery walk the teacher can have a class discussion explaining the importance of each text/graphic. Making sure that students were correct with their initial observations. 

Three-Corners:

• After the gallery walk, ask students to stand up. Students who are leaning towards the claim that the atomic bombs were necessary can go stand on the left wall. Students who are leaning towards the claim that the atomic bombs were unnecessary may go stand on the right wall of the classroom. Students who are undecided may stand at the back of the classroom. 
• Ask students to turn and tell a partner “Why they chose this side of the room?” Give 3-4 minutes for students to share. Teacher conducts whole class discussion asking various students to share their reasoning with the class. Undecided students can share what part of the research they want to dive deeper into before making a decision. 
• Students are given the Webquest Worksheet and they can work through it alone or with a partner. Before dismissing class have students turn and talk with a partner to share the most interesting thing they learned. Allow some students to share with the whole class.  
• Students choose a side to defend and work to complete the  Research Organizer . Students will choose a source, evaluate its credibility, cite evidence, and explain what the evidence shows.   
• Teachers may give students the list of possible sources, just some of the sources, or none at all (see Teacher Source List ). Modifications can be made to decide what is best for your students. 
• Students watch a video that shows an example of a Socratic seminar. Teacher has students write two higher-level questions in preparation for the Socratic seminar. Teacher may scaffold with Sample Question Stems .   
• Teacher reiterates the purpose of the inner circle is to have the discussion while the outer circle observes. Halfway through the class period the circle participants will switch. The “hot seat” is one open chair in the inner circle, where an outer circle student may sit if they have a burning piece of information to share. After sharing they return to the outer circle. After clarifying expectations, teacher supervises the Socratic seminar.  
• After the Socratic seminar students write a concluding statement, summing up their claim while also explaining the implications and relevance of this topic today.  

Vocabulary 

• Petition- a formal written request, typically one signed by many people, appealing to authority with respect to a particular cause. 
• Declaration- the formal announcement of the beginning of a state or condition. 
• Elders- a leader or senior figure in a tribe or other group. 
• Legacy- something handed down from an ancestor, or someone older in the family 

Assessment Materials   

Students participate in a Socratic seminar to show an understanding of the standards. Teacher may print a class roster and give students a check-mark each time they participate in a meaningful way. The roster and  Research Organizer can be used to assess the standards.  

Enrichment Activities 

Students may consider: 

• A tour out to the B-Reactor 
• Interviewing a docent 
• Conducting deeper research, searching in the Hanford History Project archives
• Completing a public service campaign that supports their claim 
• Writing a poem that has a tone fitting to the audience and purpose 
• Writing a letter to a government official about Hanford clean-up or necessity of keeping peace a priority 
• Publishing a speech about their claim onto YouTube 

Support and Additional Resources 

• Support for Struggling Learners: Many scaffolds are available in this lesson. Academic vocabulary is already added to gallery walk document. Consider using the question stems, and self-selecting sources for a struggling learner. Make sure closed captioning is on for all videos shown. Students may be pulled into a small group while teacher models how to analyze a source closely. Students nervous about speaking in a large group may also practice in one-on-one situations with teacher and even a small group setting beforehand. 

Contact Information 

Email us about this lesson plan  

Full lesson plan.

Download "Debating the Atomic Bombs" Lesson Plan

Students will walk around the classroom, viewing the different visual that relate to the atomic bombings.

Download Gallery Walk Visuals

As students walk around, they will fill out a T-chart worksheet.

Download Student T-Chart Worksheet

Teachers may refer to the sample T-chart.

Download Teacher Example T-Chart

Students are given a webquest worksheet.

Download Student Webquest Worksheet

Students work to complete the research organizer.

Download Research Organizer

List of possible sources.

Download Teacher Source List

Sample question stems for the Socratic seminar.

Download Sample Question Stems

Lesson Plans

Last updated: March 1, 2023

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Creation of the U.S. atomic weapons program

Manhattan project expansion under groves and oppenheimer, the first atomic bombs: trinity, hiroshima, and nagasaki, operation crossroads and the end of the manhattan project.

What led to the Manhattan Project?

Who were the most important scientists associated with the manhattan project, what did the manhattan project do, what were the immediate and long-term results of the manhattan project.

• What did J. Robert Oppenheimer do in the Manhattan Project?

Manhattan Project

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• Table Of Contents

In 1939, American scientists, many of whom had fled from fascist regimes in Europe, were aware of advances in nuclear fission and were concerned that Nazi Germany might develop a nuclear weapon. The physicists Leo Szilard and Eugene Wigner persuaded Albert Einstein to send a letter to U.S. President Franklin D. Roosevelt warning him of that danger and advising him to establish an American nuclear research program. The Advisory Committee on Uranium was set up in response. The beginning of the Manhattan Project can be dated to December 6, 1941, with the creation of the Office of Scientific Research and Development, headed by Vannevar Bush .

American physicist J. Robert Oppenheimer headed the Manhattan Project, with the goal of developing the atomic bomb , and Edward Teller was among the first recruited for the project. Leo Szilard and Enrico Fermi built the first nuclear reactor . Ernest Orlando Lawrence was program chief in charge of the development of the electromagnetic process of separating uranium-235 .

Other notable researchers included Otto Frisch , Niels Bohr , Felix Bloch , James Franck , Emilio Segrè , Klaus Fuchs , Hans Bethe , and John von Neumann . The person who oversaw the Manhattan Project, however, was not a scientist. He was Leslie Groves , a brigadier general in the U.S. Army.

The Manhattan Project produced the first atomic bomb . Several lines of research were pursued simultaneously . Both electromagnetic and fusion methods of separating the fissionable uranium-235 from uranium-238 were explored at Oak Ridge in Tennessee. The production of plutonium-239, first achieved at the University of Chicago , was further pursued at the Hanford Engineer Works in Washington state. In the meantime, at Los Alamos , New Mexico, scientists found a way to bring the fissionable material to supercritical mass (and thus explosion) and to control the timing and devised a weapon to house it. The first test, on July 16, 1945, at Alamogordo air force base in New Mexico, produced a massive nuclear explosion.

Although many physicists were opposed to the actual use of the atomic bomb created by the Manhattan Project, U.S. President Harry S. Truman believed that the bomb would persuade Japan to surrender without requiring an American invasion. Accordingly, on August 6, 1945, a U.S. airplane dropped an atomic bomb on Hiroshima , killing at least 70,000 people instantly (tens of thousands more died later of radiation poisoning). Three days later, another U.S. aircraft dropped a bomb on Nagasaki . Since then, a number of countries have concluded that possession of nuclear arms is the best way to guarantee their safety, despite fears that nuclear proliferation increases the chances of the use of such a weapon.

Manhattan Project , U.S. government research project (1942–45) that produced the first atomic bombs . See Britannica’s interactive timeline of the Manhattan Project.

American scientists, many of them refugees from fascist regimes in Europe, took steps in 1939 to organize a project to exploit the newly recognized fission process for military purposes. The first contact with the government was made by G.B. Pegram of Columbia University , who arranged a conference between Enrico Fermi and the Navy Department in March 1939. In the summer of 1939, Albert Einstein was persuaded by his fellow scientists to use his influence to present the military potential of an uncontrolled fission chain reaction to Pres. Franklin D. Roosevelt . In February 1940, $6,000 was made available to start research under the supervision of a committee headed by L.J. Briggs, director of the National Bureau of Standards (later National Institute of Standards and Technology ). On December 6, 1941, the project was put under the direction of the Office of Scientific Research and Development, headed by Vannevar Bush .

After the U.S. entered World War II , the War Department was given joint responsibility for the project, because by mid-1942 it was obvious that a vast array of pilot plants, laboratories, and manufacturing facilities would have to be constructed by the U.S. Army Corps of Engineers for the assembled scientists to carry out their mission. In June 1942 the Corps of Engineers’ Manhattan District was initially assigned management of the construction work (because much of the early research had been performed at Columbia University, in Manhattan ), and in September 1942 Brig. Gen. Leslie R. Groves was placed in charge of all Army activities (chiefly engineering activities) relating to the project. “Manhattan Project” became the code name for research work that would extend across the country.

It was known in 1940 that German scientists were working on a similar project and that the British were also exploring the problem. In the fall of 1941 Manhattan Project chemist Harold C. Urey accompanied Pegram to England to attempt to set up a cooperative effort, and by 1943 a combined policy committee was established with Great Britain and Canada . In that year a number of British and Canadian scientists moved to the United States to join the project.

If the project were to achieve timely success, several lines of research and development had to be carried on simultaneously before it was certain whether any might succeed. The explosive materials then had to be produced and be made suitable for use in an actual weapon.

Uranium-235 , the essential fissionable component of the postulated bomb, cannot be separated from its natural companion, the much more abundant uranium-238 , by chemical means; the atoms of these respective isotopes must rather be separated from each other by physical means. Several physical methods to do this were intensively explored, and two were chosen—the electromagnetic process developed at the University of California , Berkeley , under Ernest Orlando Lawrence and the diffusion process developed under Urey at Columbia University. Both of these processes, particularly the diffusion method, required large, complex facilities and huge amounts of electric power to produce even small amounts of separated uranium-235. Philip Hauge Abelson developed a third method called thermal diffusion, which was also used for a time to effect a preliminary separation. These methods were put into production at a 70-square-mile (180-square-km) tract near Knoxville , Tennessee , originally known as the Clinton Engineer Works, later as Oak Ridge .

Only one method was available for the production of the fissionable material plutonium-239 . It was developed at the metallurgical laboratory of the University of Chicago under the direction of Arthur Holly Compton and involved the transmutation in a reactor pile of uranium-238. In December 1942 Fermi finally succeeded in producing and controlling a fission chain reaction in this reactor pile at Chicago.

Quantity production of plutonium-239 required the construction of a reactor of great size and power that would release about 25,000 kilowatt-hours of heat for each gram of plutonium produced. This required the development of chemical extraction procedures that would work under conditions never before encountered . An intermediate step in putting this method into production was taken with the construction of a medium-size reactor at Oak Ridge. The large-scale production reactors were built on an isolated 1,000-square-mile (2,600-square-km) tract on the Columbia River north of Pasco , Washington—the Hanford Engineer Works .

Before 1943, work on the design and functioning of the bomb itself was largely theoretical, based on fundamental experiments carried out at a number of different locations. In that year a laboratory directed by J. Robert Oppenheimer was created on an isolated mesa at Los Alamos , New Mexico , 34 miles (55 km) north of Santa Fe . This laboratory was tasked with developing methods to reduce the fissionable products of the production plants to pure metal and fabricate the metal to required shapes. Methods of rapidly bringing together amounts of fissionable material to achieve a supercritical mass (and thus a nuclear explosion) had to be devised , along with the actual construction of a deliverable weapon that would be dropped from a plane and fused to detonate at the proper moment in the air above the target. Most of these problems had to be solved before any appreciable amount of fissionable material could be produced, so that the first adequate amounts could be used at the fighting front with minimum delay.

By the summer of 1945, amounts of plutonium-239 sufficient to produce a nuclear explosion had become available from the Hanford Works, and weapon development and design were sufficiently advanced so that an actual field test of a nuclear explosive could be scheduled. Such a test was no simple affair. Elaborate and complex equipment had to be assembled to provide a complete diagnosis of success or failure. By this time the original $6,000 authorized for the Manhattan Project had grown to $2 billion.

The first atomic bomb was exploded at 5:30 am on July 16, 1945, at the Alamogordo air base 120 miles (193 km) south of Albuquerque , New Mexico. Oppenheimer had called the site “Trinity” in reference to one of John Donne ’s Holy Sonnets . The bomb—a plutonium implosion device called Gadget —was raised to the top of a 100-foot (30-meer) steel tower that was designated “Zero.” The area at the base of the tower was marked as “Ground Zero,” a term that would pass into common parlance to describe the center of an (often catastrophic) event. The tower was surrounded by scientific equipment, with remote monitoring taking place in bunkers occupied by scientists and a few dignitaries 10,000 yards (9 km) away. The explosion came as an intense light flash, a sudden wave of heat, and later a tremendous roar as the shock wave passed and echoed in the valley. A ball of fire rose rapidly, followed by a mushroom cloud extending to 40,000 feet (12,200 meters). The bomb generated an explosive power equivalent to 15,000 to 20,000 tons of trinitrotoluene (TNT); the tower was completely vaporized and the surrounding desert surface fused to glass for a radius of 800 yards (730 meters).

The following month, two other atomic bombs produced by the project, the first using uranium-235 and the second using plutonium, were dropped on the Japanese cities of Hiroshima and Nagasaki. Neither city had been attacked during the U.S. strategic bombing campaign until that point, and planners wished to demonstrate the destructive power of the bombs. Hiroshima was selected as the primary target because of its military value; the city served as the headquarters of the Japanese Second Army. On August 6, 1945, at about 8:15 am local time, a U.S. B-29 bomber released a gun assembly fission bomb—dubbed Little Boy —above Hiroshima. The weapon detonated at an altitude of 1,900 feet (580 meters), and the explosive yield was estimated to be the equivalent of 15,000 tons of TNT. Some 70,000 people were killed instantly, and by the end of the year the death toll had surpassed 100,000. Two-thirds of the city area was destroyed.

By the morning of August 9, 1945, the Soviet Union had declared war on Japan, but the Japanese government had not yet communicated its intent to surrender to the Allies . A B-29 carrying Fat Man —a plutonium implosion bomb similar to the one used in the Trinity test—was initially dispatched to Kokura (now part of Kitakyūshū , Japan). Thick clouds and haze over Kokura prevented the bombardier from sighting the designated aimpoint, however, and the bomber proceeded to its secondary target, the port city of Nagasaki . At 11:02 am Fat Man exploded at an altitude of 1,650 feet (500 meters) northwest of the city center. The bomb detonated with the explosive force of 21,000 tons of TNT. An estimated 40,000 people were killed instantly, and at least 30,000 more would die from their injuries and radiation poisoning by the end of the year. About 40 percent of the city’s buildings were completely destroyed or severely damaged. Due to the area’s uneven terrain, a significant part of Nagasaki—particularly in the southeastern industrial and government district—was relatively unscathed . The Japanese initiated surrender negotiations the next day. By this point, Groves had notified U.S. Pres. Harry S. Truman that another bomb would be ready for delivery within a week.

On September 2, 1945, a Japanese delegation signed formal surrender documents on the deck of the USS Missouri . Shortly after the conclusion of hostilities, Manhattan Project physicist Philip Morrison traveled to Hiroshima at the request of the War Department to study the effects of the atomic bomb. Characterizing the bomb as “preeminently a weapon of saturation,” he said, “It destroys so quickly and so completely such a large area that defense is hopeless.” Horrified by what he had witnessed , Morrison would spend the rest of his life campaigning against nuclear weapons and a potential “third bomb.”

After the war, the Manhattan Project oversaw Operation Crossroads, a military-scientific experiment conducted at Bikini atoll in the South Pacific in 1946. “Able,” the first peacetime atomic weapons test, was carried out on July 1, 1946. In attendance were some 42,000 U.S. military personnel, as well as more than 100 journalists and representatives from a dozen foreign countries. A 20-kiloton atomic bomb was dropped from a B-29 and exploded at an altitude of about 520 feet (158 meters) over a fleet of about 80 decommissioned World War II naval vessels. Only five ships were sunk by the blast, and, although several more were damaged, the majority survived the explosion relatively unscathed. Within a day, radiation levels had subsided enough for the ships to be boarded and inspected. Press and foreign military observers seemed underwhelmed that the blast had not vaporized the assembled ships, but such an appraisal discounted the debilitating effect that radiation would have had on a ship’s crew. Many test animals placed throughout the fleet quickly succumbed to radiation sickness , confirming a prediction in the Bulletin of the Atomic Scientists that “a large ship, about a mile away from the explosion, would escape sinking, but the crew would be killed by the deadly burst of radiations from the bomb, and only a ghost ship would remain, floating unattended on the vast waters of the ocean.”

The second test, “Baker,” took place on July 25, 1946. A 23-kiloton device was suspended at a depth of 90 feet (27 meters) from a decommissioned landing craft in the Bikini lagoon. At the moment of the explosion, a luminous dome rose on the surface of the lagoon, followed by an opaque cloud that enveloped about half the target area. The cloud dissipated within seconds, revealing a column of ascending water that lifted the 26,000-ton battleship USS Arkansas into the air for a brief moment. The column of water, some 2,200 feet (670 meters) in diameter, rose to a height of 1 mile (1.6 km), sending spray still higher. The expanding column of spray engulfed about half the ships in the target fleet with radioactive water. Waves traveling outward from the explosion were up to 100 feet (30 meters) tall, even at a distance of 1,000 feet (some 300 meters) from the epicenter . The evaluation board of the Joint Chiefs of Staff reported that the explosion had produced intense radioactivity in the waters of the lagoon. The target ships were saturated with radioactive water so lethal that four days after the test, it was still unsafe for inspection parties to spend “any useful length of time” in the center of the target area or on any of the ships anchored there. Persistent radiation and the difficulty of decontamination led to the cancellation of “Charlie,” a planned third test that would have involved a bomb being detonated at the bottom of the Bikini lagoon.

After the conclusion of Operation Crossroads, the Manhattan District relinquished direction of the plants and laboratories under its jurisdiction to the U.S. Atomic Energy Commission (AEC), a civilian agency established by act of Congress in August 1946. Under the AEC, weapon development and testing continued along with development of the peaceful uses of atomic energy . The U.S. government disbanded the AEC under the Energy Reorganization Act of 1974 and divided its functions between two new agencies: the Nuclear Regulatory Commission , which regulates the nuclear power industry, and the Energy Research and Development Administration, which was eliminated in 1977 when the Department of Energy was created.

July 21, 2023

What Was the Manhattan Project?

The top-secret Manhattan Project resulted in the atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki in 1945

By Tom Metcalfe

Sign marking the explosion of the test of the atomic bomb at the Trinity site, N.M.

Education Images/Universal Images Group via Getty Images

The Manhattan Project was a top-secret program to make the first atomic bombs during World War II. Its results had profound impacts on history: the subsequent nuclear arms race has radically changed the political world order in ways that are still evident today.

Thousands of scientists, including theoretical physicist J. Robert Oppenheimer , took part in the Manhattan Project, often while they and their families were lodged at secret military bases in remote locations. It resulted in the two atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki in August 1945, which brought World War II to its end and probably killed more than 100,000 people .

“The Manhattan Project harnessed the enormous energy in the nucleus of the atom for the first time,” explains Cynthia Kelly, founder and president of the Atomic Heritage Foundation, a nonprofit dedicated to the history of the project and the atomic age.

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One of the project’s consequences was the creation of terrifying opposing arsenals of nuclear weapons . But it also resulted in innovations from medicine to space exploration and in the science and engineering of civilian nuclear energy, Kelly says.

The U.S. Army Corps of Engineers created the Manhattan Engineer District in June 1942 to hide the development of the atomic bomb during the war—hence that effort’s name of the “Manhattan Project.”

But historian of science Alex Wellerstein explains in an online overview that the project originated in an idea from the late 1930s—that Nazi Germany might build an atomic bomb, so the U.S. should do so first. Historical records reveal that Germany didn’t get far , but the prospect of a Nazi bomb was horrifyingly real.

Several leading researchers worked for wartime Germany, including Werner Heisenberg . Even so, many scientists who favored an American atom bomb, including Hungarian-born physicist Leo Szilard , had fled the Nazis in Europe. had fled the Nazis in Europe. 

In July 1939 Szilard and others enlisted the help of the renowned physicist Albert Einstein , then on holiday on Long Island, N.Y., to support them by writing a letter to President Franklin D. Roosevelt. The Einstein-Szilard letter , as it’s known, changed history. It prompted Roosevelt to convene a committee to investigate the possibility of building an atomic bomb, and 1941 this group became a new committee to  lay the groundwork for the full project.

These early stages involved key contributions from the U.K. and Canada. But in the end, the atomic bomb was mostly an American weapon.

After 1942 the Manhattan Project was the recognized Allied effort to build an atomic bomb. It mainly used uranium ore from a mine in what is now the Democratic Republic of the Congo, which was kept secret from the Germans.

Otherwise the project was conducted in the U.S., primarily at three top-secret towns: Oak Ridge, Tenn., where uranium was enriched until it was radioactive enough for nuclear fission; Hanford, Wash., where reactors transformed uranium into plutonium, an even more powerful nuclear fuel; and Los Alamos, N.M., where Oppenheimer directed the laboratory that designed and built experimental atomic bombs.

There were also dozens of smaller sites . And officials went to extraordinary lengths to keep it all secret.

World War II historian Alexandra Levy says most of the more than 600,000 people involved—including the thousands of scientists, engineers and technicians who worked on the weapons, as well as construction workers and the people who kept the three secret towns going—were deliberately not told their purpose.

“Most of those people did not know that the goal of the project was to build a new type of bomb,” Levy says. “Today, between the Internet and social media, it’s difficult to imagine such a large-scale endeavor remaining secret for long.”

Kelly adds, “We live in a very, very different world. Aside from one or two key senators agreeing to a blank check for the Manhattan Project, Congress and the press were kept in the dark. That would be impossible today.”

The Manhattan Project culminated in the Trinity test in New Mexico on July 16, 1945—the first detonation of a nuclear weapon. By that time, the U.S. had spent around $2.2 billion —the equivalent of around $37 billion today.

But the dangers of a Nazi bomb had faded, and Japan was now the designated target. Although Japan never had an atomic bomb program, the idea of stopping its aggression with a show of awful destruction became fixed among Manhattan Project leaders, science historian Wellerstein says.

He notes that Oppenheimer, then the charismatic director of the Los Alamos laboratory, twice voted in favor of the initial atomic bomb attack on Hiroshima —which killed tens of thousands of civilians—instead of a purely military target.

Oppenheimer is seen as essential to the success of the American atomic bomb project. “He contributed to some of the early scientific breakthroughs of the project,” Levy says. “His great gift was bringing together scientists, engineers and other technicians to collaborate on and solve problems.”

But Oppenheimer was also ambivalent about its results. In recalling his experience at the Trinity test in 1965, he quoted a story from the Hindu scripture the Bhagavad Gita about a prince, reluctant to kill his enemies, who witnessed the transformation of Krishna, an incarnation of the Hindu deity Vishnu: “ Now I am become Death, the destroyer of worlds .”

Oppenheimer was the reluctant prince, not Krishna. “He didn’t want to kill people,” Wellerstein says. “But he knew that nuclear weapons were going to be built anyway, and he felt that he had a duty to do this horrible thing.”

On the History and Technology of the Atomic Bomb. The Commitment of the Scientists

• First Online: 01 January 2015

Cite this chapter

• Vincenzo Cioci 3 , 4  

Part of the book series: History of Mechanism and Machine Science ((HMMS,volume 27))

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The development of the atomic bomb in the first half of the twentieth century marked a turning point in the history of nuclear science because it revealed the close relationships that exist among science, technology and society. In this paper the main discoveries that led to the scientific and technological development of the atomic bomb are presented together with the commitment of scientists who tried to avoid possible harmful uses of the results of their researches.

In this work a deep examination of the writings of some of these scientists is introduced, some of which are still unpublished, although already quoted by several authors, with the purpose to highlight the relevance of their position against the bomb to the present day. In this sense the content of the paper may appear as a novelty within the history of science and technology; even if it cannot be a unique story.

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The Historiography of “Hitler’s Atomic Bomb”

After Crossroads: The Fate of the Atomic Bomb Target Fleet

Introduction

1 Rutherford won the Nobel Prize for Chemistry in 1908 “for his investigations into the disintegration of the elements and the chemistry of radioactive substances”, although the chemist of the team was Soddy. He gained due recognition only with the Nobel Prize in 1921 “for his contributions to our knowledge of the chemistry of radioactive substances and his investigations into the origin and nature of isotopes”. In 1913, in fact, he had found that certain elements exist in two or more forms with different atomic weights but they are chemically indistinguishable. Between 1911 and 1913, he had also formulated the Law of radioactive displacement, which refers to the fact that the emission of an α particle by an element moves it back two places in the periodic table, while the emission of a β particle situates it in one position forward. His naming to the Royal Swedish Academy of Sciences was proposed by Rutherford (and supported by Thomson), as if to repay the debt contract with Soddy on the occasion of the Nobel Prize in 1908.

In March 1903, Pierre Curie (1859–1906) and Albert Laborde (1878–1968) had measured the heat developed in a Bunsen ice calorimeter from a known amount of radio in a defined time. They found enormous values of the order of 100 calories per hour for a single gram of radium (Curie and Laborde 1903 ). These authors, however, did not consider it possible that this heat was developed at the expense of the internal energy of the radium but they thought that it came from a source outside the atom, of unknown nature (on this topic see Soddy 1904b , Chap. XI entitled “The energy of radio-active change”, pp. 165–170).

Soddy ( 1953 , f 282, 2, line 6).

In this science fiction novel, H. G. Wells predicts, about 20 years in advance, the discovery of artificial radioactivity, the industrial use of atomic energy and a global conflict resulting from the use of “atomic bombs”, with the devastation of the main cities of the planet (Wells 1914 ).

See the 6th paragraph and Cioci ( 2008 ).

Soddy ( 1915 , p. 13, line 19).

The Sydney Morning Herald ( 1935 , f 124, line 43).

Soddy ( 1949 , p. 128, column 1, line 52). For the significant contribution made by Soddy to economics, linked to his commitment to the prevention of war, see Cioci ( 2009a ).

Heavy water was considered to be slow motion par excellence because deuterium has a light nucleus, suitable to subtract kinetic energy from neutrons, and being already formed by a neutron and a proton it was believed to be not “inclined” to absorb neutrons. The research started eventually in Montreal after the war with construction of the atomic pile ZEEP, the origin of the CANDU reactors.

F. Rasetti ( 1958–1968 , p. 11, line 2). Information about this document can be found in Amaldi ( 1990 , p. 175, footnote 15). The document was widely quoted by Battimelli and De Maria in the “Preface” of Amaldi ( 1997 ) and by Maltese ( 2003 ).

Ivi, line 4.

Battimelli ( 2002 ), Maltese ( 2003 ). These authors reported Edoardo Amaldi’s assessments; he considered the decision to work in the Manhattan Project as a necessary assumption of responsibility by scientists to prevent the world being conquered by the Nazis using nuclear weapons: “If I had found myself there (in front of this dramatic dilemma), after deep and painful considerations on which it was my moral duty of man asked to decide whether cooperate in the defense of democracies … or lock myself in my private life, doing nothing to fight the dictatorship, I would have eventually opted for the first solution” (Amaldi 1997 , p. 98, line 32).

Amaldi ( 1979 , p. 199, column 2, line 13).

Associated Press ( 1933 , p. 1, line 18). A summary of the presentation at the British Association is published in the Times of September 12, 1933, p. 7 and of Nature, no. 132, pp. 432–433 (16 September 1933).

Szilard ( 1972 , pp. 729–732; 1978, pp. 45–46).

E. Amaldi ( 1984 , p. 160, line 27).

The exact critical mass for uranium 235 is 52 kg. The critical mass for plutonium 239 is 10 Kg.

Frisch and Peierls ( 1940b , p. 86, line 15).

United States Atomic Energy Commission ( 1971 , p. 12, line 4).

Weisskopf ( 1967 , p. 40, column 1, line 19; 42, column 1, line 11).

Smyth ( 1945 , p. 254, line 16).

Rotblat ( 1985 , p. 18, line 22).

Committee on Social and Political Implications ( 1946 , p. 3, column 3, line 34).

Oppenheimer ( 1948 , p. 66, line 45).

The account of A. K. Smith is entitled “A peril and a Hope” by a famous expression of Oppenheimer according to which nuclear weapons would constitute a danger and a hope for humanity because given the power of these terrible means of destruction humankind would have to give up war to settle international disputes and would have to create a united world under the law and humanity.

Smith and Weiner ( 1980 ).

Oppenheimer ( 1966 , line 20).

Lilienthal et al. ( 1946 , p. 24, line 15).

For further arguments in favour of this conclusion see Cioci ( 2004 ).

General Advisory Committee ( 1949 , p. 155, line 39).

Ivi, line 21.

Ibidem, 156, line 6.

See Capuozzo and Cioci ( 2010 ).

E.g. see: Teller ( 1950 ).

Amaldi E (1979) Gli anni della ricostruzione (The years of reconstruction). Giornale di Fisica 20(3):186–225

Google Scholar  

Amaldi E (1984) From the discovery of the neutron to the discovery of nuclear fission. Physics Reports 111(Sept):1–332

Article   Google Scholar  

Amaldi E (1990) The case of physics (Il caso della fisica. Le conseguenze culturali delle leggi razziali. Atti dei convegni lincei, Roma 84: 107–133). In: Battimelli G, Paoloni G (eds) 20th century physics: essays and recollections. A selection of historical writings by Edoardo Amaldi (1998). World Scientific, Singapore

Amaldi E (1997) Da via Panisperna all’America (From via Panisperna to America). Editori Riuniti, Roma

Anderson HL, Fermi E, Hanstein HB (1939) Production of neutrons in uranium bombarded by neutrons. Physical Review 55:797–798.

Associated Press (September 1933) Atom-powered world absurd, scientists told. New York Herald Tribune, pp 1, 37

Battimelli G (2002) Era un ragazzo di via Panisperna (He was a boy from via Panisperna). Lett Matematica 42:15–21

Bohr N (1936) Neutron capture and nuclear constitution. Nature 137:344–348, 351

Article   MATH   Google Scholar  

Bohr N (1939) Disintegration of heavy. Nuclei. Nature 143:330.

Bohr N, Kalckar F (1937) On the transmutation of atomic nuclei by impact of material particles. I. General theoretical remarks. Mat-Fys Medd Dan Vidensk Selsk 14(10):1–40

Bohr N, Wheeler JA (1939) The mechanism of nuclear fission. Physical Review 56:426–450

Brown A (2012) Keeper of the nuclear conscience. The life and works of Joseph Rotblat. Oxford University Press, New York

Butcher SI (2005) The origins of the Russell-Einstein Manifesto. Pugwash History Series 1:3–35

Capuozzo L, Cioci V (2010) La Fisica, le origini della biologia molecolare e dell’Ingegneria genetica: il caso della conferenza di asilomar (Physics, the origins of molecular biology and genetic engineering: the case of the Asilomar Conference). In: Giannetto E, Giannini G, Toscano M (eds) Relatività, quanti, chaos e altre rivoluzioni della fisica (Proceedings of the XXVII SISFA Congress). Guaraldi, Rimini, pp 357–364

Cioci V (2004) Una rivisitazione del caso Oppenheimer (A review of Oppenheimer case). In: Tucci P, Garuccio A, Nigro M (eds) Proceedings of the XXIII SISFA Congress. Progedit, Bari, pp 131–144

Cioci V (2007) Storia e confronto di tre diverse posizioni di fisici contro la bomba atomica (History and comparison of three different positions of physicists against the atomic bomb). In: Leone M, Preziosi B, Robotti N (eds) L’eredità di Fermi Majorana e altri temi. Atti del XXIV Congresso della Società Italiana degli Storici della Fisica e dell’Astronomia. Proceedings of the XXIV SISFA Congress. Bibliopolis, Naples, pp 211–215

Cioci V (2008) Science fiction e realtà: La liberazione del mondo di H. G. Wells e il suo influsso sugli scienziati atomici. (Science fiction and reality: The world set free by HG Wells and his influence on the atomic scientists). In: Pitrelli N, Ramani D, Sturloni G (eds) Proceedings of the VI Italian national conference on science communication. Polimetrica, Monza, pp 97–102

Cioci V (2009a) Frederick Soddy, un chimico alle frontiere della conoscenza, fra Fisica, Economia, Matematica ed Ecologia (Frederick Soddy, a chemist at the frontiers of knowledge, among physics, economics, mathematics and ecology). In: Calascibetta F (ed) Proceedings of the XIII National Congress of History and Fundamentals of Chemistry, Excerpt from vol 127, Memoirs of Physical and Natural Sciences, Proceedings of the Italian National Academy of Sciences called Academy of Forty, ser. 5, vol 33, part II, vol II, pp 319–330

Cioci V (2009b) Edoardo Amaldi e il rifiuto delle applicazioni militari della fisica nucleare (Edoardo Amaldi and the refusal of the military applications of nuclear physics). Proceedings of the XLVII AIF Congress, Supplement to LNFS 42(3): 50–58

Committee on Social and Political Implications (1946) A report to the secretary of war (Frank report). Bulletin of Atomic Scientists 1(10):2–4, 16

Curie P, Laborde A (1903) Sur la chaleur dégagée spontanément par les sels de radium. Comptes Rendus 136(sem.1):673–675

Einstein A (1905) Does the inertia of a body depend upon its energy content? (Ist die Trägheit eines Körpers von seimen Eneirgieinhalt abhängig? Annalen der Physik, ser. 4, 18:639–641). In: Einstein A (1989) Collected papers of Albert Einstein, vol 2. Princeton University Press, Princeton, pp 172–174

Einstein A (1907) On the relativity principle and the conclusion drawn from it (Relativitätsprinzip und die aus demselben gezogenen Folgerungen, Jahrbuch der Radioaktivität 4:411–62; 5:98–99). In: Einstein A (1989) Collected papers of Albert Einstein, vol 2. Princeton University Press, Princeton, pp 252–311

Einstein A (1910) Principe de relativité et ses conséquences dans la physique moderne. Archives des sciences physiques et naturelles (Series 4), 29:5–28,125–244

Einstein A (1989) Collected Papers of Albert Einstein, vol 2. The Swiss years: writings, 1900–1909. Princeton University Press, Princeton. (English translation supplement. Beck A (tr), Havas P (con), Buchwald DK (g ed))

Fermi E (1934) Possible production of elements of atomic number higher than 92. Nature 133:898–899

Fermi E, Amaldi E, D’Agostino O, Rasetti F, Segré E (1934) Artificial radioactivity produced by neutron bombardment—I. Proceedings of the Royal Society of London A 146(857):483–500

Frisch O (1939) Physical evidence for the division of heavy nuclei under neutron bombardment. Nature 143:276

Frisch O, Peierls R (1940a) Memorandum on the properties of a radioactive “superbomb”. In: Serber R (ed) The Los Alamos primer. University of California Press, Berkeley, pp 80–83

Frisch O, Peierls R (1940b) On the construction of a “super-bomb”; based on a nuclear chain reaction in uranium. In: Serber R (ed) The Los Alamos primer. University of California Press, Berkeley, pp 83–88

General Advisory Committee (1949) Report of GAC to the U. S. atomic energy commission, October 30. In: York HF (ed) The advisors. Oppheneimer, teller and the superbomb (1976). Freeman and Company, San Francisco, pp 150–159

Hahn O, Strassmann F (1939) Concerning the existence of alkaline earth metals resulting from neutron irradiation of uranium (Über den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle. Die Naturwissenschaften 27:11–15). Am J Phys 32:9–15 (English Translation)

Hinshaw VGJ (1949) Einstein’s social philosophy. In: Schilpp AP (ed) Albert Einstein: philosopher-scientist. Volume VII in the Library of Living Philosophers, MJF Books, New York, pp 649–661

Jonas H (1984) The imperative of responsibility: in search of an ethics for the technological age (Das Prinzip Verantwortung, Insel Verlag, Frankfurt am Main, 1979) (trans: H Jonas, D Herr). University of Chicago Press, Chicago

Jonas H (1997) Tecnica medicina ed etica. Prassi del principio responsabilità. (Technik, Medizin und Ethik: Zur Praxis des Prinzips Verantwortung. Insel Verlag, Frankfurt am Main, 1985) (trans: P Becchi, A Benussi). Einaudi, Torino. (Not translated into English yet)

Jones VC (1985) Manhattan: the army and the atomic bomb. United States Army, Washington (Center of military history)

Kipphardt H (1964) In the matter of J. Robert Oppenheimer; a play freely adapted on the basis of the documents. Hill & Wang, New York

Lilienthal DE (Chairman), Barnard CI, Oppenheimer JR, Thomas CA, Winne HA (1946) A report on the international control of atomic energy prepared for the secretary of state’s committee on atomic energy (Acheson-Lilienthal report). U. S. Government Printing Office, Washington

Maltese G (2003) Enrico Fermi in America. Una biografia scientifica: 1938–1954 (Enrico Fermi in America. A scientific biography: 1938–1954). Zanichelli, Bologna

Meitner L, Frisch OR (1939) Disintegration of uranium by neutrons: a new type of nuclear reaction. Nature 143:239–40

Oppenheimer JR (1948) Physics in the contemporary world. Bulletin of Atomic Scientists 4(3):65–68, 85–86

Oppenheimer JR (1966) Draft letter to David Bohm, 2 December Library of congress. Manuscript division, Papers of J. R. Oppenheimer, box 20

Pais A (1982) Subtle is the lord. The science and the life of Albert Einstein. Oxford University Press, New York

Peierls R (1974) Oppenheimer J. Robert. In: Gillispie CC (ed) Dictionary of scientific biography, vol X. Charles Scribner’s Sons, New York, pp 213–218

Ramsay W, Soddy F, (1904) Further experiments on the production of helium from radium. Proceedings of the Royal Society of London 73:346–358

Rasetti F (1955) Fermi. Science 121(1344):449–451

Rasetti F (1958–1968) Biographical notes and scientific work of Franco Rasetti, unpublished typescript preserved in the Amaldi Archives, Department of Physics, Rome University “La Sapienza”, sc. 1E, fasc. 22

Rasetti F (1968) Enrico Fermi e la fisica italiana (Enrico Fermi and the Italian physics). In: Celebrazioni Lincee in ricordo di Enrico Fermi. Accademia Nazionale dei Lincei, Roma, pp 11–19

Rhodes R (1986) The making of atomic bomb. Simon & Schuster, New York

Rotblat J (1985) Leaving the bomb project. The Bulletin of the Atomic Scientists 41(7):16–19

Russell BAW, Einstein A (1955) Texts of scientists’ appeal for abolition of war. The New York Times, 10 July, p 25. (The Russell-Einstein Manifesto). Issued in London, 9 July 1955, and signed also by Born M, Bridgman PW, Infeld AL, Joliot-Curie F, Muller HJ, Pauling L, Powell CF, Rotblat J, Yukawa H. Reprinted in: Bone AG (ed) The Collected Papers of Bertrand Russell, vol 28. Man’s Peril, 1954–1955. Routledge, London and New York, pp 259–262

Rutherford E, Soddy F (1902a) The cause and nature of radioactivity, parts I and II. Philosophical Magazine (Series 6) 4:370–396, 569–585

Rutherford E, Soddy F (1902b) The radioactivity of thorium compounds, parts I and II. Transactions of Journal of the Chemical Society 81:837–860, 837–851

Rutherford E, Soddy F (1903) Radioactive change. Philosophical Magazine (Series 6) 5:576–591

Smith AK (1971) A peril and a hope. The scientists’ movement in America 1945–47. The MIT Press, Cambridge

Smith AK, Weiner C (eds) (1980) Robert Oppenheimer. Letters and recollections. Harvard University Press, Cambridge

Smyth HD (1945) Atomic energy for military purposes. The official report on the development of the atomic bomb under the auspices of the United States Government, 1940–1945. Princeton University Press, Princeton. (Reprinted by Maple Press, York, Pennsylvania)

Soddy F (1903a) Some recent advances in radioactivity. Contemporary Review 83(May):708–720

Soddy F (1903b) Possible future applications of radium. Times Literature Supplement 17:225–226

Soddy F (1904a) Radium. Professional Papers of the Royal Corps of Engineers 29:237–251

Soddy F (1904b) Radio-activity: an elementary treatise from the standpoint of the disintegration theory. The electrician, London

Soddy F (1906) The internal energy of elements. Journal of the Institution of Electrical Engineers 37:140–147

Soddy F (1909) The interpretation of radium. G. P. Putnam’s Sons, New York

Soddy F (1915) The social effect of recent advances in physical sciences. In: Professor Frederick Soddy Papers, Bodleian Library, Oxford, MS Eng Misc b179, ff. 542–556

Soddy F (1926) Wealth, virtual wealth and debt. The solution of the economic paradox. George Allen & Unwin Ltd, London

Soddy F (1934) Suggestion to the ordinary fellows of the royal society for a reform group to uphold their rights. In: Professor Frederick Soddy Papers, Bodleian Library, Oxford, MS. Eng. misc. b170, f 147

Soddy F ( 1945) The moving finger writes […] Cavalcade, August 18, pp 8–9

Soddy F (1949) The story of atomic energy. Nova Atlantis, London

Soddy F (1953) Correspondence with Sir Harold Hartley. In: Professor Frederick Soddy Papers, Bodleian Library, Oxford, MS Eng Misc b189, ff 281–285

Szilard L (1972) The collected works of Leo Szilard: scientific papers. Edited by Feld BT, Weiss Szilard G. The MIT Press, Cambridge

Szilard L (1978) His Version of the Facts. Selected Recollections and Correspondence. Edited by Weart SR, Weiss Szilard G. The Mit Press, Cambridge

Szilard L, Zinn WH (1939) Instantaneous emission of fast neutrons in the interaction of slow neutrons with uranium. Physical Review 55:799–800

Teller E (1950) Back to the laboratories. Bulletin of Atomic Scientists 6(3):71

The Sydney Morning Herald (1935) Royal society. Demand for Reform., December 23, N.S.W., Australia. In: Professor Frederick Soddy Papers, Bodleian Library, Oxford, MS. Eng. misc. b170, f 124

United States Atomic Energy Commission (1971) In the matter of J. Robert Oppenheimer. Transcript of hearing before personnel security board and texts of principal documents and letters. Foreword by Stern PM. The MIT Press, Cambridge

von Halban H, Joliot F, Kowarski L (1939) Liberation of neutrons in the nuclear explosion of uranium. Nature 143:470–471

Weart S (1982) The road to Los Alamos. Journal De Physique (Colloque C8, suppl au n 12) 43:301–313

Weisskopf V (1967) The Los Alamos years. In: A memorial to Oppenheimer. Physics Today 20(10):39–42

Wells HG (1914) The world set free. A story of mankind. Macmillan and Company, London

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Acknowledgments

I thank Professor Giovanni Battimelli, Referent for Documents and Sources for the History of Physics, Department of Physics, University “La Sapienza” of Rome, who helped me in the consultation of the Edoardo Amaldi Archives.

My special thanks is addressed to Colin Harris, Superintendent of the Special Collections Reading Rooms, for his help in finding the unpublished writings of Frederick Soddy , to Dr. Chris Fletcher, Keeper of Special Collections, and to the Bodleian Library, Oxford University, which owns them, for permission given on the basis of ‘non-exclusive rights’ to quote and to paraphrase them.

I am grateful to Bonnie Coles for helping me in the examination and retrieval of the writings of Robert Oppenheimer at the Manuscript Division of the Library of Congress (USA).

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Vincenzo Cioci

Research Group on Physics Education and History of Physics, University of Calabria, Cosenza, Italy

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Correspondence to Vincenzo Cioci .

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Department of Physics, Lille 1 University Science and Technology, Villeneuve d’Ascq, France

Raffaele Pisano

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Cioci, V. (2015). On the History and Technology of the Atomic Bomb. The Commitment of the Scientists. In: Pisano, R. (eds) A Bridge between Conceptual Frameworks. History of Mechanism and Machine Science, vol 27. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-9645-3_7

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It’s time to end the myth that the US needed to drop atomic bombs to end World War II | Opinion

It was disappointing to see debunked myths about World War II published recently in The Kansas City Star as if they were undisputed facts. Those assertions were that:

President Harry Truman’s use of atomic bombs on Hiroshima and Nagasaki was necessary to end the war.

The war was then only at a midpoint.

The use of these weapons saved “half million lives.”

In truth, by June 1945, Japan had been militarily defeated, its once powerful Imperial Navy and air services capable of little resistance, according to Mark Weber, director of the Institute for Historical Review, in his 1997 essay, “ Was Hiroshima Necessary? ”

Gen. Dwight D. Eisenhower said of these bombings: “ The Japanese were ready to surrender , and it wasn’t necessary to hit them with that awful thing.”

Most American military leaders criticized the bombings publicly after the war, including Truman’s chief of staff, Adm. William D. Leahy and even the well-known war hawk Gen. Curtis LeMay, who led the bombings over Tokyo, and who said in a press conference on Sept. 20, 1945: “The war would have been over in two weeks without the Russians entering and without the atomic bomb.” When asked to clarify, LeMay said, “The atomic bomb had nothing to do with the end of the war at all.”

Gar Alperovitz — perhaps the historian who knows the issue best, having written the books “Atomic Diplomacy: Hiroshima and Potsdam” and ”The Decision To Use The Atomic Bomb,” with seven collaborators and 112 pages of endnotes — says that the 1990 declaration by J. Samuel Walker, chief historian of the U.S. Nuclear Regulatory Commission, convinced him that the use of atomic weapons on Japan was unnecessary. Walker said:

“The consensus among scholars is that the bomb was not needed to avoid an invasion of Japan to end the war within a relatively short time. It is clear that alternatives to the bomb existed and that Truman and his advisors knew it.”

On Aug. 5, 2005, Kai Bird and Martin J. Sherwin, co-authors of “American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer,” wrote an article in The Los Angeles Times entitled “The myths of Hiroshima.” In it, they said:

“The hard truth is that the bombings were unnecessary. A million lives were not saved. Indeed, McGeorge Bundy, the man who first popularized this figure, later confessed that he had pulled it out of thin air in order to justify the bombings in a 1947 Harper’s magazine essay he had ghostwritten for Secretary of War Henry L. Stimson.” (Since the total American casualties in WWII were 405,000, the suggestion of an invasion of Japan taking one million or half a million American lives is ludicrous, and Bundy vacillated between one million and half million.)

“By the time historians were given access to the secret files necessary to examine this subject with care, the myth of huge numbers of American, British and Japanese lives saved had already achieved the status of accepted history,” Rufus E. Miles Jr. wrote in the journal International Security in fall of 1985. Had they focused on the “striking inconsistencies between” the wartime documents and “those parts of the principal decision-makers’ memoirs that dealt with estimates of lives saved. Had they done so, and followed the subject where it led, they would have been forced to conclude that the number of American deaths prevented by the two bombs would almost certainly not have exceeded 20,000 and would probably have been much lower, perhaps even zero,” Miles concluded.

The real truth was suppressed for some time, but now that the records are available, it is time for the real story to come out.

Michael Childers is a consultant and journalist in Kansas City. He has been published regularly in Aircraft Interiors International magazine, Experience Magazine, Inflight magazine and others.