What “Oppenheimer” Misses About The Decision to Drop the Bomb

“I wanted to save half a million boys on our side…I never lost any sleep over my decision.”

President Harry S. Truman

Time and time again, we hear this repeated: Truman had to drop the atomic bombs to save millions of lives. Sometimes it is American soldiers saved. Or someone’s grandfather or great-grandfather is alive because of the atomic bombs. Often, someone who doesn’t want to sound too crude will discuss how the bombs also saved millions of Japanese lives. 

It is easy to frame the atomic bombings as the lesser of two great evils or a weighty decision placed on Truman after the death of President Franklin D. Roosevelt.

Debates surrounding the justifications for the atomic bombings of Hiroshima and Nagasaki have been reignited by Christopher Nolan’s biopic, “Oppenheimer.” What follows is a deep exploration of archival data and relevant literature where we demonstrate the casualty myth that continues to frame discussions today. The reality of the situation at the time was far more complex and nuanced than the repeated narratives of a clean bomb or avoiding an invasion. However, the “millions of deaths” was a persuasive campaign launched — contrary to the facts of the case — to justify the “necessity” of atomic bombs. 

“Everything and the Kitchen Sink” Approach 

The day before the Trinity Test at Los Alamos, New Mexico, on July 15, 1945, the Joint War Plans Committee, a high-level advisory group to the Joint Chiefs of Staff, presented their casualty estimates. Barton Bernstein, in his 1986 Bulletin of the Atomic Scientists article titled “A Postwar Myth: 500,000 US Lives Saved,” wrote that the committee recognized it was impossible to make an accurate estimate, but their educated guesses for three different invasion plans were: First, the most likely, an attack on southern Kyushu, followed by the Tokyo plain — about 40,000 Americans dead, 150,000 wounded, and 2,500 missing. Second, the less likely attack on southern Kyushu, followed by northwestern Kyushu — 25,000 Americans dead, 105,000 wounded, and 2,500 missing. And third, an attack on southern Kyushu, followed by northwestern Kyushu and then the Tokyo plain — 46,000 dead, 170,000 wounded, and 4,000 missing in action.

On June 18, 1945, two days after the Trinity Test, Truman met with Secretary of War Henry L. Stimson, Assistant Secretary of War John J. McCloy, Secretary of the Navy James Forrestal, and the Joint Chiefs of Staff, including General George C. Marshall and Admiral Ernest J. King. In this meeting, they discussed the details of a proposed invasion of Japan, what it would entail, and even the casualty estimates of US personnel, advocating the first option for a southern Kyushu attack. 

What is striking about the meeting minutes is that it is not a decision about whether to drop atomic bombs or invade. The men proceeded under the assumption that the intended bombs would be used and the invasion would still proceed even if Japan did submit to an unconditional surrender. Marshall read a statement by the Joint Chiefs of Staff for Truman, which set forth the target date for invasion as November 1, 1945. Their reasoning was the following: First, “if we press preparations we can be ready.” Second, “our estimates are that our air action will have smashed practically every industrial target worth hitting in Japan as well as destroying huge areas in the Jap cities.” Third, “the Japanese Navy, if any still exists, will be completely powerless.” Finally, “our rear action and air power will have cut the Jap reinforcement capability from the mainland to negligible proportions.”

What is striking about the meeting minutes is that it is not a decision about whether to drop atomic bombs or invade. The men proceeded under the assumption that the intended bombs would be used and the invasion would still proceed even if Japan did submit to an unconditional surrender.

Weatherwise, the group reasoned that November 1 was ideal and would allow minimum time for the Japanese to prepare. Thus, one can see, as Alex Wellerstein argues, it was not a “decision” of bomb or invade, it was always to “bomb and to invade, and to have the Soviet invade, and to blockade, and so on. It was an ‘everything and the kitchen sink’ approach to ending the war with Japan, though there were a few things missing from the ‘everything… .’” 

What became known as Operation Olympic, the consensus then from the Joint Chiefs of Staff was to invade Kyushu, the southern Island of Japan. As seen in the maps below, after Kyushu, the plan was to continue toward the Tokyo plain. The Joint Chiefs viewed the Kyushu operation as “essential to a strategy of strangulation and appears to be the least costly worthwhile operation following Okinawa. The basic point is that a judgement [sic] in Kyushu is essential, both to tightening our stranglehold of blockade and bombardment of Japan and to forcing capitulation by invasion of the Tokyo Plain.”

So what were the casualty estimates given to Truman by military planners for the November 1 invasion of Kyushu?

There were very specific and clear discussions of casualty estimates of US troops for the proposed invasion. These differ immensely from the post-war inflated estimates of millions, especially those based on Okinawa numbers. Of course, casualties are impossible to accurately predict; nevertheless, it is essential to understand what military planners thought at the time. The Joint Chiefs acknowledged that “Our experience in the Pacific War is so diverse as to casualties that it is considered wrong to give any estimate in numbers.” However, they cited the following data as relevant to the discussion:

Additionally, the total casualties in Japan for the 13 months of General Douglas MacArthur’s operation “from 1 March 1944 through 1 May 1945 shows 13,742 US killed compared to 320,165 Japanese killed, or a ratio of 22:1.” 

The Joint Chiefs clearly conveyed to Truman that there was “reason to believe that the first 30 days in Kyushu should not exceed the price we have paid for Luson,” i.e., less than 31,000 killed, wounded, or missing. King supported this assessment by distinguishing a crucial difference between Okinawa and Kyushu. Namely, there had only been “one way to go on Okinawa. This meant that straight frontal attack against a highly fortified position. On Kyushu, however, landings would be made on three fronts simultaneously” with more room to maneuver. Hence, according to the Joint Chiefs of Staff statement, the “nature of the objective area gives room for maneuver, both on land and by sea.” Indeed, King put a “realistic casualty figure for Kyushu…somewhere between the number experienced by General MacArthur in the operation on Luson and the Okinawa casualties.” Hence, tens of thousands, not hundreds of thousands, and nowhere near millions.

Other studies that cite higher casualty numbers for a full invasion of Japan –– as high as 220,000 killed, wounded, and missing –– were not presented to Truman by the Joint Chiefs of Staff and were not in line with the phased invasion plans. Forrestal pointed out to Truman that “even if the decision were to be a siege of Japan for a year or a year and a half, that the capture of Kyushu would still be essential.” Hence, what was given to Truman were the best-laid plans for the most likely invasion of Kyushu along with the Russian entry into the war. 

The ultimate invasion of Honshu and the Tokyo plain were not believed necessary at the time and would be considered in March 1946 at the earliest, emphasizing that, indeed, this was not a decision of bomb or invade but to bomb and invade. Marshall conveyed his personal view that “air power alone was not sufficient to put the Japanese out of the war” and the “operation against Kyushu was the only course to pursue.” 

The Joint Chiefs also viewed the Soviet entry into the war as crucial. They said, “The impact of Russian entry on the already hopeless Japanese may well be the decisive action levering them into capitulation at that time or shortly thereafter if we land in Japan.” Truman agreed with them, and stated that one of his “objectives with the coming [Potsdam] conference would be to get from Russia all the assistance in the war that was possible.” Truman ended by saying that he “considered the Kyushu plan all right from a military standpoint, and so far as he was concerned, the Joint Chiefs of Staff could go ahead with it; but we can do this operation and then decide as to the final action later.”

The Casualty Myth

In July 1946, the US Strategic Bombing Survey Summary report was issued on the Pacific War. It was undertaken at the direction of Truman to conduct a study of the effects of all types of air attacks in the war against Japan. This civilian committee went to Japan to understand both Japanese and American war planning to “present an analysis of the factual material gathered by the Survey and their general appraisal.”

The conclusion of the survey committee is astonishing. According to the committee, “Based on a detailed investigation of all the facts, and supported by the testimony of the surviving Japanese leaders involved, it is the Survey’s opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated.”

Now, of course, it is impossible to know if this would have actually been the case historically. However, it is incredible that those tasked with investigating Japanese and American records at the time determined that the Japanese would have surrendered even without the atomic bombs, the Russian invasion, or the planned American invasion of Kyushu. 

Even today, deeply ingrained in the American consciousness is the myth that millions were saved (presumably from death) by dropping the atomic bombs and avoiding an invasion. There are several flaws with this line of argumentation.

More recent scholarship by Tsuyoshi Hasegawa suggests that it was indeed the combination of Hiroshima and the Soviet invasion of Manchuria that led to Japanese surrender. He based this on archival evidence from Japan, the United States, and the Soviet Union and makes a compelling nuanced argument. Ultimately, history cannot be run on counterfactuals. Nonetheless, those who were tasked to investigate the end of the war drew radical conclusions that should continue to inform today’s debate. 

So, what does all this mean? After the successful test at Trinity, the military estimates of an invasion presented to Truman were less than 31,000 killed, wounded, or missing — far from Truman’s post-war inflation of half a million boys killed. Even today, deeply ingrained in the American consciousness is the myth that millions were saved (presumably from death) by dropping the atomic bombs and avoiding an invasion. There are several flaws with this line of argumentation. First, the plan was always to both bomb and invade, the either-or logic is a false dichotomy. Second, the invasion was planned for November 1, 1945 with a best-case scenario, three months after the atomic bombings, with Japan already decimated from conventional and incendiary bombings and under a naval blockade. Thus, there was no guarantee of the necessity of an invasion. Third, the Joint Chiefs saw a Soviet invasion as central to victory, something that is rarely discussed in US circles. Though, they perhaps never anticipated a Soviet invasion of Japanese-occupied Manchuria between the bombings of Hiroshima and Nagasaki on August 8, 1945. 

How, then, did the myth of millions of lives saved become cemented in the American consciousness that still shapes debates about the end of World War II today?

The Social Construction of Lives Saved

Bernstein, in his 1986 Bulletin of the Atomic Scientists article, argues that there was an active campaign by Truman and Stimson to craft the public narrative of “the decision” to bomb or invade, weighing the lives of millions of Americans. US public opinion at the time stood firmly behind the use of the atomic bombs to end World War II with the wide suppression of photos and videos from the aftermath, John Hersey’s “Hiroshima” took up the entirety of the August 1946 issue of The New Yorker and threatened to turn public opinion. Its haunting personal account of the bombings brought the feeling of the horrors of the bomb into American households. Of course, this presented a threat to the narrative of the necessity to end World War II, so Truman sent Stimson and others on a public relations offensive.

In response to Truman’s request, physicist and MIT President Karl T. Compton wrote for The Atlantic in December 1946 an article titled, “If the Atomic Bomb had Not Been Used,” crafting the narrative of millions of dead Americans and Japanese. He wrote: “I believe, with complete conviction, that the use of the atomic bomb saved hundreds of thousands — perhaps several millions — of lives, both American and Japanese; that without its use the war would have continued for many months; that no one of good conscience knowing, as Secretary Stimson and the Chiefs of Staff did, what was probably ahead and what the atomic bomb might accomplish could have made any different decision.”

Truman himself responded to Compton almost immediately after it was published. He called his article “the first sensible statement I have seen on the subject.” 

Truman also asserts that Compton’s analysis was fair “except that the final decision had to be made by the President and was made after a complete survey of the whole situation had been made.” This runs counter to the consensus discussed by Wellerstein that Truman’s “decision” was more one of non-interference. Indeed, Wellerstein notes that “Truman, for his part, while he did not authorize the actual bombing in any explicit way (he was shown the bombing order, but he did not issue it nor was his approval required, though he could have vetoed it), did, on August 10, 1945, re-assert nuclear authority by prohibiting future bombing activity without his explicit permission.” Wellerstein cites General Leslie Groves’ direct quote that Truman’s role in the atomic bombing of Hiroshima and Nagasaki as “one of noninterference — basically, a decision not to upset the existing plans.” Thus, from that point forward, the president made it very explicit that his office was in charge of the atomic bomb and its uses, not the military.

As you can read here, Truman in his letter to Compton is asserting his “decision narrative” that just was not the case. He ends the letter asserting that the “Japanese were given fair warning and were offered the terms, which they finally accepted, well in advance of the dropping of the bomb. I imagine the bomb caused them to accept the terms.” Thus, Truman is actively asserting both his central role to the “decision” to drop the bombs, as well as the inflated casualty estimates.

In the letter, Truman clearly states that in addition to Compton’s Atlantic article, he instructed Stimson “to assemble the facts and get them into record form.” 

With Stimson’s instruction from Truman, as outlined in the above letter to Compton, he penned “The Decision to Use the Atomic Bomb” for the February 1947 Issue of Harper’s Magazine.

In the essay, Stimson reiterated the plan explored above: “We were planning an intensified sea and air blockade, and greatly intensified strategic air bombing, through the summer and early fall, to be followed on November 1 by an invasion of the southern island of Kyushu. This would be followed in turn by an invasion of the main island of Honshu in the spring of 1946. The total US military and naval force involved in this grand design was of the order of 5,000,000 men; if all those indirectly concerned are included, it was larger still.” 

He then went on to assert that: “I was informed that such operations might be expected to cost over a million casualties, to American forces alone. Additional large losses might be expected among our allies, and, of course, if our campaign were successful and if we could judge by previous experience, enemy casualties would be much larger than our own.”

Stimson stated that: “No explanation can change that fact, and I do not wish to gloss over it. But this deliberate, premeditated destruction was our least abhorrent choice. The destruction of Hiroshima and Nagasaki put an end to the Japanese war. It stopped the fire raids and the strangling blockade; it ended the ghastly specter of a clash of great land armies.” He ended the piece in the following manner: “In this last great action of the Second World War we were given final proof that war is death. War in the twentieth century has grown steadily more barbarous, more destructive, more debased in all its aspects. Now, with the release of atomic energy, man’s ability to destroy himself is nearly complete. The bombs dropped on Hiroshima and Nagasaki ended a war.”

Years later in 1952, Truman received an inquiry from James Lea Cate, a consultant in the Historian’s Office of the Department of the Air Force and co-editor of a seven-volume book on Army Air Forces in World War II. In 1953, Truman responded with this letter:

In this letter Truman is attempting to craft the post-war narrative along the lines of the early Compton and Stimson PR. He cites the conversation with the Joint Chiefs of Staff that we examined above, inflating casualties to up to a million American and Japanese lives. He dismisses the Russian invasion of Japanese occupied Manchuria as irrelevant to the end of the war. Furthermore, he asserts that he was the one who “ordered atomic bombs dropped.” Truman succinctly concludes for the history books, “Dropping the bombs ended the war, saved lives, and gave the free nations a chance to face the facts.” One can see the PR campaign underway from the very beginning to long after the war, to shape the understanding of the atomic bombings on the American public that remains pervasive to this day.

There are three things that are important to note. First, Truman did not make the “decision” to drop the bombs, his was one of noninterference, to not disrupt existing plans to drop the bombs. Second, bomb or invade was set out as a binary choice, neglecting the plan to do all of the above and negating the role of the Soviet invasion in Japanese decision-making to end the war. Third, the PR campaign by Truman, Stimson, Compton, and others began to steadily inflate the numbers of anticipated casualties. Bernstein cites MacArthur, US commander in the Pacific, who believed that the casualties and deaths would not be as high as the rate at Normandy and Okinawa. 

While it is impossible to know how many may have actually died, the myth of millions of lives saved continues to shape discussions of the justifications of atomic use. What is the cultural production of the framing of the debates as hundreds of thousands of Americans saved?

MacArthur’s plans for the first stage, the November invasion of southern Kyushu, estimated total casualties (dead plus wounded) in the first three months at well under 100,000. When he discovered that some of his staff, in putting together “purely academic” estimates, had forecast possibly 110,000 casualties or more, he cabled Marshall on June 18, 1945, “I do not anticipate such a high rate of loss…it must be remembered that the several preced­ing months will involve practically no losses…The hazard and loss will be greatly less­ened if an attack is launched [by the Soviets] from Siberia sufficiently ahead of our target date to commit the enemy to major combat. I most earnestly recom­mend no change in Olympic.” Ultimately, Bernstein concludes that the “myth of 500,000 American lives saved thus seems to have no basis in fact. No US military planner in 1945, even after Hiroshima, would have put the number over 200,000, and many placed it much lower — near 40,000.” 

Not So Moral After All 

The “Oppenheimer” film has reignited debates surrounding the necessity of dropping the atomic bombs on Hiroshima and Nagasaki. We sought to examine in-depth one crucial element of this framing: casualty estimations of the invasion of Japan. As the archival data demonstrates, post-war discussions by Truman, Stimson, and others sustained a campaign to inflate the casualty estimates of a US invasion of Japan. 

The military leaders advising Truman after Trinity placed the total casualty numbers in the tens of thousands, not 500,000 or millions. Furthermore, Truman cemented his narrative that he made the fateful “decision” to drop the bombs rather than one of noninterference. While it is impossible to know how many may have actually died, the myth of millions of lives saved continues to shape discussions of the justifications of atomic use. What is the cultural production of the framing of the debates as hundreds of thousands of Americans saved?

The PR campaign by Truman and Stimson of the casualty myth served to cement the United States as a responsible and moral power post-World War II. While having mastered weaponized atomic technology, we only deployed it against our enemies out of a utilitarian calculation of least harm, with deep moral regret. This solidifies the US identity as the moral leader for the world throughout the Cold War and beyond. Claiming to have saved millions of American lives is a linguistic trick to put those both at the time and today arguing against the necessity of the atomic bombings to end the war at an instantaneous disadvantage. Framing the debate in this way makes the answer of “we had to drop the atomic bombs” a foregone conclusion. 

War is always uncertain; but at the time, those that authored Truman’s Strategic Bombing survey deemed the atomic bombings unnecessary. The Joint Chiefs of Staff estimated only tens of thousands of casualties and emphasized the necessity of the Soviet invasion to force Japan’s surrender. Nonetheless, discussing these numbers does not take away from the fact that — by some estimates — more than 25 million soldiers and civilians were killed in the Pacific theater alone. Arguments for and against the use of the atomic bombs should continue to recognize the devastation of war on human lives. Indeed, Truman’s post-war inflation of estimated casualties continues to shape debates today, and we hope that this excavation of the existing archival evidence will shift the narrative.

Correction: A previous version of this article misdated a meeting between Truman and Secretary of War Henry L. Stimson, Assistant Secretary of War John J. McCloy, Secretary of the Navy James Forrestal, and the Joint Chiefs of Staff, including General George C. Marshall and Admiral Ernest J. King. That meeting occurred on June 18, not July 18.