The Manhattan Project

by Cynthia C. Kelly

  The criticisms of the atomic attacks and the conclusions of the Strategic Bombing Survey had very little discernible impact on popular support for Truman’s decision. Although the existence of atomic weapons and the possibility that they might at some time be used against American cities was troubling, they did not lead to widespread reappraisal or disapproval of the use of atomic bombs against Japan. Nevertheless, even occasional expressions of dissent offended some Manhattan Project veterans. One leading figure in the building of the bomb, James B. Conant, decided to take action to counter the critics.

  Conant was convinced that a combat demonstration of the destructive power of atomic bombs was essential to prevent their future use. It was, he believed, “the only way to awaken the world to the necessity of abolishing war altogether.” Along with scientific advisers to the Interim Committee and other colleagues, Conant reasoned that the use of the bomb would not only force a prompt Japanese surrender but also shock leaders around the globe into seeking international control of nuclear weapons. “We have had some skeptics express doubts as to whether [the bomb] is indeed a revolutionary weapon,” he remarked in 1947, “but what skepticism there would have been had there been no actual use in war!”

  Conant had little patience with critics of the use of the bomb against Japan. Although their influence was slight, he worried about the consequences if they undermined public support for Truman’s decision. One harmful result might be that the chances for arms control would be diminished. Conant believed that only if the American people clearly demonstrated their willingness to use their atomic arsenal would the Soviet Union be amenable to nuclear arms control agreements. Further, he feared that questions about the use of the bomb would influence teachers and students in the future in ways that distorted history. “You may be inclined to dismiss all this talk [criticizing the use of the bomb] as representing only a small minority of the population, which I think it does,” Conant told a friend in September 1946. “However, this type of sentimentalism, for so I regard it, is bound to have a great deal of influence on the next generation. The type of person who goes in to teaching, particularly school teaching, will be influenced a great deal by this type of argument.”

  In order to head off the potential influence of those who raised doubts about whether the dropping of atomic bombs on Japan had been a sound and proper action, Conant persuaded Henry L. Stimson to write an article to explain why they were used. Stimson, who was writing his memoirs in retirement, reluctantly took on the assignment, assisted by the collaborator on his memoirs, McGeorge Bundy, the son of former War Department aide Harvey H. Bundy and future national security adviser to Presidents John F. Kennedy and Lyndon B. Johnson. The article, which appeared in the February 1947 issue of Harper’s Magazine, deliberately refrained from directly challenging the critics of the use of the bomb. It provided a judicious, dispassionate, and seemingly authoritative treatment of the Manhattan Project and the decision to drop the bomb, complete with excerpts from Stimson’s diary and other documents. It presented the use of the bomb as the “least abhorrent choice” that accomplished its objective of ending the war quickly. Stimson reported that the atomic attacks were authorized in order to avoid an invasion of Japan, which, he said, might have been “expected to cost over a million casualties to American forces alone.”

  More than any other single publication, Stimson’s article influenced popular views about Truman’s decision to use the bomb. The information it provided and the respect that its author commanded made its arguments seem unassailable. The article received wide circulation and acclaim, and Conant was satisfied that it had fulfilled his objective of effectively countering the complaints of critics of the use of the bomb. However, the article, despite the aura of authority that it presented, was not a full accounting; it glossed over or omitted important aspects of the events that led to the bombing of Hiroshima and Nagasaki. It offered only hints of alternatives to the use of the bombs or Stimson’s own support for modifying the demand for unconditional surrender. It failed to cite the influence of diplomatic considerations and gave the misleading impression that Truman and his advisers carefully considered whether or not the bomb should be dropped. The most vivid of the article’s arguments was that the use of the bomb prevented over 1 million American casualties by making an invasion unnecessary. The source of Stimson’s figure is not clear; even Bundy could not recall precisely the basis for the casualty estimate. Stimson was not the first to suggest the figure of 1 million, but after his article appeared, that number, or often an embellished variation of it, became indelibly etched into the mythology of the decision to use the bomb.

  The first scholarly history of the decision to use the bomb raised some questions about the standard view without undermining its basic premises. In Japan Subdued: The Atomic Bomb and the End of the War in the Pacific, published in 1961, former State Department official Herbert Feis concluded that “the impelling reason for the decision to use [the bomb] was military—to end the war victoriously as soon as possible.” He accepted the argument that if an invasion had been necessary, it might have cost hundreds of thousands of American lives. But Feis discussed alternatives to the bomb at length, expressed regret that the United States did not give Japan an explicit warning about the pending use of atomic weapons at the time of the Potsdam Declaration, and agreed with the conclusion of the Strategic Bombing Survey that the war would have ended by the end of 1945 without the bomb, Soviet entry into the war, or an American invasion. And although he supported the claims of hundreds of thousands of American casualties or deaths in an invasion, he admitted that he could not find evidence to confirm those estimates.

  In 1965, political economist Gar Alperovitz published a book titled Atomic Diplomacy, which was based on his doctoral dissertation. He challenged the traditional explanation more directly and much more critically than Feis had done by suggesting that the bomb had not been needed to end the war at the earliest possible time. Drawing on recently opened sources, especially the papers and diary of Henry L. Stimson, he asserted that the United States dropped it more for political than for military reasons. Alperovitz argued that Truman did not seriously consider alternatives to the bomb because he wanted to impress the Soviets with its power. In his analysis, the bomb was used primarily to intimidate the Soviets rather than to defeat the Japanese. Alperovitz pointed out that many sources were still not available to scholars and clearly stated that his findings could not be regarded as conclusive.

  Atomic Diplomacy received a great deal of popular and scholarly attention and triggered a spirited historiographical debate. By the mid-1970s, after the publication of several works that drew on extensive research in primary sources, including important studies by Barton J. Bernstein and Martin J. Sherwin, scholars reached a general consensus that combined the traditional interpretation with Alperovitz’s “revisionist” position. They concluded that the primary motivation for dropping the bomb was to end the war with Japan but that diplomatic considerations played a significant, if secondary, role in the Truman administration’s view of the new weapon’s value.

  Over the next fifteen years, new evidence relating to the use of the bomb stirred further scholarly investigation and debate. It included a handwritten diary that Truman jotted down at Potsdam and personal letters that he sent to Mrs. Truman. Those documents greatly enriched the record on the president’s views of the bomb in the summer of 1945, but they did not provide conclusive evidence on his thoughts about the likelihood that the war would end without an invasion, the need for the bomb, the role of diplomatic considerations in deciding to use the bomb, or the extent to which he weighed those issues. In a similar manner, the opening of personal papers and official records of other high-level policymakers and their staffs in the 1970s and 1980s broadened the documentary base for studying the decision to use the bomb but did not offer definitive answers to questions that had intrigued scholars and sometimes provoked sharp debate among them.

  Nevertheless, by the
late 1980s, specialists who studied the available evidence reached a broad, though hardly unanimous, consensus on some key issues surrounding the use of the bomb. One point of agreement was that Truman and his advisers were well aware of alternatives to the bomb that seemed likely, but not certain, to end the war within a relatively short time. Another was that an invasion of Japan would probably not have been necessary to achieve victory. A third point of general agreement in the scholarly literature on the decision to use the bomb was that the postwar claims that the bomb prevented hundreds of thousands of American combat deaths could not be sustained with the available evidence. Most students of the subject also concurred that political considerations figured in the deliberations about the implications of the bomb and the end of the war with Japan. On all of those points, the scholarly consensus rejected the traditional view that the bomb was the only alternative to an invasion of Japan that would have cost a huge number of American lives. At the same time, most scholars supported the claim of Truman and his advisers that the primary motivation for dropping atomic bombs on Hiroshima and Nagasaki was to end the war at the earliest possible moment—that is, for military reasons.

  The debates among scholars and the conclusions that they reached about the decision to use the bomb were not widely known to the general public, which from all indications remained wedded to the traditional view that Truman faced a categorical choice between the bomb and an enormously costly invasion. The chasm between the myth that the public embraced and the findings of scholars who examined the documentary evidence led to a bitter controversy when the Smithsonian Institution’s National Air and Space Museum made plans in the early 1990s to present a major exhibit on the bomb and the end of World War II. The show would be built around a section of the restored fuselage of the Enola Gay, the plane that dropped the atomic bomb on Hiroshima (the entire plane was too large to display). Museum curators designed an exhibit that was intended both to commemorate the valor and sacrifices of American war veterans and to reflect scholarly findings on the decision to use the bomb. But this proved to be an impossible task. By raising questions about the traditional and popularly accepted interpretation of why the United States dropped the bomb, the original script for the exhibit set off a firestorm of protest.

  The Enola Gay controversy highlighted the gap between scholarly and popular views on the decision to use the bomb. But even among scholars who recognize the lack of validity of the mythological explanation, the issue remained a source of contention. Indeed, the widespread publicity surrounding the fiftieth anniversary of Hiroshima made it clear that some scholars sharply contested the consensus that prevailed in the late 1980s. They particularly took issue with the arguments that the war would have ended soon without the bomb and that the projected casualty figures for an invasion were much lower than postwar claims by Truman and his advisers.

  The most important issues that cannot be fully settled because they require speculation and extrapolation from available evidence include (1) how long the war would have continued if the bomb had not been used; (2) how many casualties American forces would have suffered if the bomb had not been dropped; (3) whether an invasion would have been necessary without the use of the bomb; (4) the number of American lives and casualties an invasion would have exacted had it proven necessary; (5) whether Japan would have responded favorably to an American offer to allow the emperor to remain on the throne before Hiroshima, or whether such an offer would have prolonged the war; and (6) whether any of the other alternatives to the use of the bomb would have ended the war as quickly on a basis satisfactory to the United States.

  Those questions go to the heart of historiographical disputes among scholars on Truman’s decision to use the atomic bomb. They cannot be answered in a way that will be accepted by all scholars or more casual students interested in the topic. The traditional view of the use of the bomb that Stimson and Truman and many others advanced after World War II was appealing in part because it was unambiguous. If Truman had in fact faced a choice between authorizing the bomb and ordering an invasion that would have cost hundreds of thousands of American lives, the decision to use the bomb would have been obvious and, in the minds of most Americans then and later, incontestable. But the existence of evidence that shows a vastly more complex situation introduces ambiguity and controversy into the issue. The best that scholars can do in addressing the issues is to draw conclusions based on sources that help reconstruct the context of events in the summer of 1945.

  Why Does This Decision Continue to Haunt Us?

  This article was written by Gar Alperovitz, a Professor of Political Economy at the University of Maryland, and published on August 3, 2005, to highlight the still vibrant discussions about the decision to use the atomic bomb sixty years earlier.

  From “Hiroshima After Sixty Years: The Debate Continues”

  BY GAR ALPEROVITZ

  This weekend marks the 60th anniversary of the August 6, 1945 bombing of Hiroshima. One might think that by now historians would agree on all the fundamental issues. The reality, however, is just the opposite: All the major issues involved in the decision are still very much a matter of dispute among experts. An obvious question is why this should be so after so many years.

  Did the atomic bomb, in fact, cause Japan to surrender? Most Americans think the answer is self-evident. However, many historical studies—including new publications by two highly regarded scholars—challenge the conventional understanding. In a recently released Harvard University Press volume drawing upon the latest Japanese sources, for instance, Professor Tsuyoshi Hasegawa concludes that the traditional “myth cannot be supported by historical facts.” By far the most important factor forcing the decision, his research indicates, was the Soviet declaration of war against Japan on August 8, 1945, just after the Hiroshima bombing.

  Similarly, Professor Herbert Bix—whose biography of Hirohito won the 2000 Pulitzer Prize for general nonfiction—also writes in a recent article that “the Soviet factor carried greater weight in the eyes of the emperor and most military leaders.”

  Many Japanese historians have long judged the Soviet declaration of war to have been the straw that broke the camel’s back—mainly because the Japanese military feared the Red Army more than the loss of another city by aerial bombardment. (They had already shown themselves willing to sacrifice many, many cities to conventional bombing!)

  An intimately related question is whether the bomb was in any event still necessary to force a surrender before an invasion. Again, most Americans believe the answer obvious—as, of course, do many historians. However, a very substantial number also disagree with this view. One of the most respected, Stanford University Professor Barton Bernstein, judges that all things considered it seems “quite probable—indeed, far more likely than not—that Japan would have surrendered before November” (when the first landing in Japan was scheduled.)

  Many years ago Harvard historian Ernest R. May also concluded that the surrender decision probably resulted from the Russian attack, and that “it could not in any event been long in coming.” In his new book Hasegawa goes further: “[T]here were alternatives to the use of the bomb, alternatives that the Truman Administration for reasons of its own declined to pursue.”

  (On the other hand, one recent writer, Richard Frank, argues Japan was still so militarily powerful the U.S. would ultimately have decided not to invade. He justifies the bombing not only of Hiroshima but of Nagasaki as well. Japanese historian Sadao Asada believes that “there was a possibility Japan would not have surrendered by November” on the basis of the Russian attack alone.)

  What did the U.S. military think? Here there is also dispute. We actually know very little about the views of the military at the time. However, after the war many—indeed, most—of the top World War II Generals and Admirals involved criticized the decision. One of the most famous was General Eisenhower, who repeatedly stated that he urged the bomb not be used: “[I]t wasn’t necessary to hit them with that awful
thing.” The well-known “hawk,” General Curtis LeMay, publicly declared that the war would have been over in two weeks, and that the atomic bomb had nothing to do with bringing about surrender. President Truman’s friend and Chief of Staff, five star Admiral William D. Leahy was deeply angered: The “use of this barbarous weapon at Hiroshima and Nagasaki was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender… [I]n being the first to use it, we… adopted an ethical standard common to the barbarians of the Dark Ages.”

  Some historians believe such statements may have been made partly to justify postwar funding requests by the various military services. Several years after the war General George C. Marshall did state publicly that he believed the bombings were necessary. On the other hand, long before the atomic bomb was used Leahy’s diary shows he judged the war could be ended. And Marshall is on record months before Hiroshima as suggesting that “these weapons might first be used against straight military objectives such as a large naval installation and then if no complete result was derived from the effect of that… we ought to designate a number of large manufacturing areas from which the people would be warned to leave—telling the Japanese that we intend to destroy such centers.…”

  Why was the bomb used? The conventional view, of course, is that it was to save as many lives as possible. But if this is so, several historians now ask, why did President Truman and his chief adviser Secretary of State James Byrnes make it harder for Japan to surrender? Specifically, why did they remove assurances for the Japanese emperor from the July 1945 Potsdam Proclamation warning Japan to surrender? The assurances were strongly recommended by U.S. and British military leaders, and removing them, they knew, would make it all but impossible for Japan to end the war.