From: A History of Our Time: Readings on Postwar America, William H. Chafe and Harvard Sitkoff, ed. New York, Oxford: Oxford University Press, 1991. pp.20-30.

Return to "World War II
and the Cold War"

Reprinted from the Bulletin of the Atomic Scientists (December 1985), by permission. Endnotes omitted.

As Robert Messer observes, the new information reveals that "contrary to his public justification of the bombings as the only way to end the war without a costly invasion of Japan, Truman had already concluded that Japan was about to capitulate." Beyond this crucial point the materials throw considerable light on two controversial historical questions:

The first is whether there actually was anything like a "decision" to use the bombs. Some have argued that it is more accurate to say that Truman was simply carried along, on the basis of assumptions that he inherited, or by the momentum of events, or both.

The second has to do with just how much of the decision, or assumption-decision, to use the bomb must be ascribed to political diplomatic considerations related to the Soviet Union.

In recent years several historians, urging the assumption theory, have stressed the continuity between the Roosevelt and Truman periods. Since my own work helped initiate the case for an assumption based theory, let me state now that the idea must be handled with considerable care. Even if the theory is accepted, it is all too easy to ignore crucial elements of choice in connection with Hiroshima.

For instance, it is simply not true that the use of the atomic bomb was never challenged, as Secretary of War Henry L. Stimson later wrote. Several top leaders--General Dwight D. Eisenhower, Admiral William D. Leahy, Under-secretary of the Navy Ralph A. Bard, Assistant Secretary of War John L. McCloy, Acting Secretary of State Joseph E. Grew and Stimson himself--at various points urged Truman not to use the bomb or to use other methods first.

There is also the matter of what assumptions Truman actually did inherit. 'There is no doubt that part of the legacy was a policy concerning international control of atomic weapons promulgated by Franklin D. Roosevelt and his top officials. This was to foster an American, and partially British, monopoly. Truman did not, however, inherit a clear policy on the use of the bomb. Rather, what evidence we have suggests that Roosevelt had doubts about using the bomb against Japan--and that in his last conversations on the subject he himself was raising the possibility of a "demonstration."

Truman, in any case, knew virtually nothing about Roosevelt's position. Moreover, while Stimson, General Leslie R. Groves, a number of scientists, and several other high officials associated with the Manhattan Project from the Roosevelt period undoubtedly assumed early on that the bomb would be used, Truman's main policy adviser, Secretary of State James F. Byrnes, was not part of that group. (And Admiral William Leahy, the chief of staff whom Truman inherited from Roosevelt and, simultaneously, presiding officer of the Joint Chiefs of Staff, was against the bombing.)

Finally, and far more important, are changes which occurred throughout the summer of 1945. Whatever assumptions Truman may have inherited, these changes presented decision-makers with a new situation.

Here the new evidence is particularly illuminating. In reviewing the history of Hiroshima, one must be extremely careful about statements and judgments made at different times between April 12, 1945, when Truman became president, and the August 6 bombing. It is almost certainly true, for instance, that American leaders assumed the bomb, like any weapon, would be used against Japan in the early summer of 1945--up to, say, the end of June. I use the qualifier "almost certainly" because there is also evidence to the contrary: At the request of the White House, Leo Szilard met with Truman's key adviser, James Byrnes, on May 28, 194--two-and-a-half months before Hiroshima. According to Szilard, "Byrnes did not argue that it was necessary to use t he bomb against the cities of Japan in order to win the war.... Mr. Byrnes's ... view [was] that our possessing and demonstrating the bomb would make Russia more manageable." Admiral Leahy was also convinced that the war was essentially over by mid-June.

In any event, in the six weeks or so before Hiroshima the situation in Japan changed dramatically. First, the intensity of Japanese peace initiatives increased--in Switzerland, Sweden, and, we now know, in Portugal. As early as May 12, 1945, almost three months before Hiroshima, William Donovan, the head of the Office of Strategic Services (OSS) personally advised the president of indications that Japan might surrender if the terms included a provision that the emperor (regarded as a deity) would not be re moved. Thereafter others--including, most importantly, Acting Secretary of State Joseph Grew and Stimson--urged such a change at different times. And we know from several sources that although Truman may have preferred to make no change, he had no objection in principle to the provision, and, of course, ultimately accepted it.

The United States had also, of course, cracked the Japanese code early in the war. In mid-June, and then very actively on into July, the emperor became involved in attempting to arrange a surrender, using Moscow as the negotiating channel. The evidence on this--and U.S. leaders'' knowledge of the emperor's initiative--is now well established. (Robert C. Butow's Japan's Decision to Surrender is the classic work.) The mere fact that the emperor, traditionally aloof from politics, instigated the diplomatic move was extraordinary. We also know that Truman clearly understood what was happening; afterwards he confirmed his awareness of the main cables. The new evidence from the diaries adds to our sense of the president's personal assessment; in these pages Truman straightforwardly terms the most important intercepted message the "telegram from Jap Emperor asking for peace."

In a new edition of Atomic Diplomacy, I have reviewed additional intelligence and other information which helps clarify how U.S. officials understood what was happening, especially in the six or seven weeks before Hiroshima. It is enough to say here that many top officials understood that Japan's situation had changed drastically. The following (often ignored) illustrations help illuminate the shifting environment in which policy was being developed:

Admiral Leahy's diary entry of June 18, 1945, just short of two months before Hiroshima: "It is my opinion at the present time that a surrender of Japan can be arranged with terms that can be accepted by Japan and that will make fully satisfactory provision for America's defense."

After the war Leahy wrote: "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.... My own feeling is that in being the first to use it, we had adopted an ethical standard common to the barbarians of the Dark Ages.... I was not taught to make war in that fashion, and wars cannot be won by destroying women and children."

General Dwight D. Eisenhower's report of his response when Stimson briefed him on the forthcoming use of the bomb:

During his recitation of the relevant facts, I had been conscious of a feeling of depression and so I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives....

Japan was, at that very moment, seeking some way to surrender with a minimum loss of ³face².... It wasn't necessary to hit them with [that] awful thing.

Eisenhower met with Truman on July 20, 1945 and urged him not to use the bomb, a fact recently confirmed by the late General Omar N. Bradley, but rarely cited in studies of the period.

Undersecretary of the Navy Ralph Bard also met with Truman, just before Potsdam, to advise another course. Bard, who resigned his official post on duly 1, 1945, wrote a memo dated June 27, which included the following paragraphs:

During recent weeks I have. . . had the feeling very definitely that the Japanese government may be searching for some opportunity which they could use as a medium of surrender.... This country could contact representatives from Japan . . . and make representations with regard to Russia's position and. . . give them some information regarding the proposed use of atomic power, together with whatever assurances the President might care to make with regard to the Emperor of Japan.... It seems quite possible to me that this presents the opportunity which the Japanese are looking for.

I don't see that we have anything in particular to lose.... The only way to find out is to try.

The assistant to the Secretary of the Navy, Admiral Lewis L. Strauss (later chairman of the Atomic Energy Commission) proposed a demonstration of the new weapon over a Japanese redwood like forest. "The war was very nearly over. The Japanese were nearly ready to capitulate."

Several other important military figures also illuminate the shifting appraisal of Japan's collapse. General Curtis LeMay, who has repeatedly declared that use of the atomic bomb was unnecessary, reportedly felt that Japan would have surrendered in two weeks (The atomic bomb "had nothing to do with the end of the war"). Army Air Force Chief, General Henry "Hap" Arnold, demanded that a statement be entered into the record of the Joint Chiefs of Staff on July 16, 1945, indicating his view that the war could easily be ended by September or October 1945 without an invasion. General Douglas MacArthur was never asked about the atomic bomb; on several occasions after the war he indicated his view that it was unnecessary. The chief British military figure, General Hastings Ismay, was filled with "revulsion" at the report that the atomic bomb had been successfully tested and could now be used: "For some time past it had been firmly fixed in my mind that the Japanese were tottering."

In many studies suggesting the near unanimity of support for using the bomb, such information is ignored or played down. Yet this information helps to clarify the way in which at least some key policy- makers viewed the situation; and, since several of them pressed their views in meetings with the president, it contributes to an assessment of what Truman must have understood. Such evidence also provides background for a consideration of other aspects of the newer materials.

The collapse of Japan during the summer of 1945--which challenged the initial assumption that the bomb would be used--must be understood in still another context: at the time, U.S. officials recognized that the Soviet Union's forthcoming declaration of war would almost certainly force Japan to surrender. The planned date for Soviet entry was August 8, 1945 (amended by one week at Potsdam). Hiroshima was destroyed on August 6, 1945; Nagasaki on August 9, 1945.

We now know that after the successful Alamogordo test U.S. Ieaders tried to stall Moscow's entry so that (as one official's diary put it) the Soviets would not get "so much in on the kill, thereby being in a position to press for claims against China." But that is not the first point to focus upon. Rather, it is that during the summer of 1945 Japan's situation deteriorated so rapidly that Truman had available an obvious option to end the war. All he really had to do was wait a week or so for the Soviet declaration to see whether his advisers were right.

In mid-June General Marshall pointed out that "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."

With the situation in Japan worsening, a month later the Combined U.S-U.K. Intelligence Staffs advised (as General Ismay summarized for Churchill): "If and when Russia came into the war against Japan, the Japanese would probably wish to get out on al most any terms short of the dethronement of the Emperor."

The new diary evidence confirms that Truman understood the advice he was receiving on the significance of the Soviet attack well before Hiroshima. On July 17, 1945, when Stalin told him personally that the Red Army would march, Truman's private diary shows him noting: "Find Japs when that comes about."

And, of course, there was plenty of time. The full invasion of Japan was not scheduled until March 1946; even an initial landing on Kyushu was still three months in the future. Moreover, the invasion date could easily have been postponed. (According to Admiral Leahy, Truman told him that, should negotiations take longer, time was not a major consideration if this would avoid an invasion.)

Truman's order to drop the atomic bomb at a time when he knew the war was soon likely to be over is--as Messer observes--"devastating" to the orthodox case that he took the step only because he wished to avoid a costly invasion. However, the significance extends further.

Given Truman's awareness of the Japanese peace initiatives and his understanding of the power of a Soviet declaration of war, a key question is: Why did the initial assumption that the bomb would be used continue among some people and not among others?

The evidence had become increasingly clear by early July that, from a military point of view, Japan was finished. By mid-July it was exceedingly doubtful that Truman believed the war would end by invasion. Moreover, several top military figures clearly understood this reality--and were shocked that, in these changed circumstances the bomb would still be used.

Who did not recognize the changed circumstances? Or, to put it another way, who refused to alter the early assumption? The military leaders went along with the president's decision, but they were not the source of initiative. It was Secretary of State Byrnes, Truman's chief adviser, and other officials most directly involved in diplomacy toward the Soviet Union who appeared to have been most unwilling or unable to alter their views.

Byrnes's general viewpoint is consistent and clear. He saw the atomic bomb as a way to impress the Soviets. The evidence is now massive on this point. A few of the numerous and by now well known diary and other accounts will illustrate:

From another report by Leo Szilard on his May 28, 1945 meeting with Byrnes:

"Byrnes . . . was concerned about Russia's postwar behavior. Russian troops had moved into Hungary and Rumania; Byrnes thought it would be very difficult to persuade Russia to withdraw her troops from these countries, and that Russia might be more manageable if impressed by American military might. I shared Byrnes's concern about Russia's throwing around her weight in the postwar period, but I was completely flabbergasted by the assumption that rattling the bomb might make Russia more manageable.

From Ambassador Joseph Davies diary during the Potsdam Conferences: Byrnes' attitude that the atomic bomb assured ultimate success in negotiations disturbed me more than his description of its success amazed me.... I told him the threat wouldn't work and might be irreparable harm."

From Secretary of the Navy James V. Forrestal's diary: "Byrnes said he was most anxious to get the Japanese affair over with before the Russians got in, with particular reference to [the Manchurian ports of] Dairen and Port Arthur."

From Secretary of War Stimson's diary after Potsdam: "I found that Byrnes was very much against any attempt to cooperate with Russia. His mind is full of his problems with the coming meeting of foreign ministers and he looks to having the presence of the bomb in his pocket, so to speak, as a great weapon to get through the thing."

It is also now clear that, on the basis of advice (from Stimson and--though the record is less clear--probably from Byrnes) about the bomb's importance to diplomatic relations with Moscow, Truman postponed the Potsdam meeting with Stalin until after the atomic bomb had been proven. The president wanted to have what Stimson called his 'master card' in hand before negotiating on Europe. The Alamogordo test took place on July 16, 1945; the Potsdam meeting began on July 17, 1945.

We do not know for sure whether Byrnes, like Leahy and Eisenhower, clearly recognized that Japan was already finished and that the bomb was therefore not needed--but that he wanted to use it anyway. Szilard's report suggests this view. A more generous interpretation is that he and the president simply got so caught up in the assumption that the bomb would be vital to their diplomacy that they blinded themselves to information which was evident to other high-ranking officials.

However, the new evidence also calls in question the whole assumption-based theory. Since Truman had the readily available option of simply waiting for the shock of the Soviet declaration of war, the evidence suggests that he appears knowingly to have rejected this choice in favor of using the bomb first. The explanation for this decision--and decision it was--appears to have been political, not military. As a plethora of diary and other evidence powerfully suggests, he and especially Byrnes wished to avoid the Red Army's entrance into Manchuria and northern China and the enhanced Soviet political influence this would bring.

Because so many documents make it so obvious that by the end of July top U.S. officials were deeply concerned about securing U.S. objectives in Manchuria and northern China, perhaps many have ignored the fact that in so doing they were consciously rejecting what seemed the easiest way to bring about surrender. If there is an unmistakable ongoing assumption, it is that, as Truman and Byrnes repeatedly stressed at Potsdam, U.S. economic and political interests in Manchuria and northern China--the "Open Door"--had to be maintained; thus, accordingly, Soviet influence had to be opposed.

• Further doubts about "ongoing assumption" theories are raised by the fact that this was not a passive act; great efforts were made both to rush the atomic bomb project and to stall the Soviets.

Although a narrow focus on ending the war cannot be excluded as an important presidential motive, the new evidence suggests that at the decision-making level the decision or assumption that the bomb would be used appears to have been sustained--in July and early August--primarily by political considerations related to the Soviet Union. The "Soviet factor," in short, becomes central to any explanation of how the atomic bomb came to be used.

We still do not have the full story of Hiroshima. There are huge gaps, particularly in our understanding of what happened between the two key actors, Truman and Byrnes.

We do know that Truman relied heavily on the enormously prestigious Byrnes, a man who had been his senior and mentor in the Senate; that he spent the month leading up to Hiroshima with him, first on shipboard and then sharing a villa at Potsdam; that Byrnes kept other key advisers away from the President; that Truman had designated Byrnes as the lead man in connection with the bomb.

But there is much we do not know. For instance, the decision to postpone negotiations with Stalin until the bomb had been tested was a very important one. Yet we have almost no information on precisely what advice Byrnes (as opposed to Stimson) gave Truman in April and May. We do know, however, that it was Byrnes who was responsible for preparing the U.S. position for the meeting, and that he was also advising Truman about the bomb.

Throughout the summer we know that Truman and Byrnes met regularly in private, but we have almost no information on their discussions, even though the meetings between the two men both in Washington and subsequently--far more than the work of the Interim Committee, the scientists' efforts, or even top military meetings--were almost certainly where much real strategy was formulated.

Nor do we know much about the details of the many meetings between the president and his chief of staff, Admiral Leahy, who was very much against the bombing. As presiding officer of the Joint Chiefs of Staff, Leahy was in a key role, but only very sketchy and occasional diary entries exist. Allen Dulles, who was handling the Japanese negotiations through Switzerland for the OSS, was called to Potsdam, but we know little about precisely what happened there. It appears likely that, had the nuclear test failed at Alamogordo, Dulles would have been sent back to arrange a quick Japanese surrender as he had done with Italy.

It is also curious that while Eisenhower reported challenging Stimson on the decision, he never disclosed that he met with Truman and urged him not to use the bomb. Why? What considerations were expressed by the president? We do not know.

In fact, although we now know a great deal about the attitudes of many key actors during the summer of 1945, we actually know surprisingly little about how Truman himself viewed several points. The two most interesting periods--the weeks in April, May, and June which encompass the private talks with Byrnes while he was developing atomic policy for the president but before he was officially in office, and shipboard talks between Truman, Byrnes, and possibly Leahy on the way to Potsdam--are almost a complete blank. Were others as reluctant as Eisenhower to discuss very private and potentially embarrassing facts? (When doing the original research on Atomic Diplomacy, I interviewed Benjamin V. Cohen, the New Dealer who served as a special assistant to Byrnes; he fell silent when asked about the relationship of Byrnes's diplomacy to the Hiroshima bombing. He said he "didn't remember" in response to numerous questions which other documents reveal were at the center of attention when he was assisting Byrnes.)

One final point: We know that the Japanese did not respond positively to the Potsdam proclamation; the usual version is that they rejected it. A number of historians have noted that the term they used--mokusatsu--can be translated in several ways: "ignore," "treat with silent contempt," "take no notice of," among others. It is sometimes argued that U.S. Ieaders unfortunately chose to interpret the term as a full rejection--and then went ahead with the bombing.

However, we now know that Truman was advised by OSS Director William Donovan on August 2, 1945, four days before Hiroshima, that Japanese officials in Switzerland tried to clarify the meaning of their government's response. Both the Japanese chief of staff and the foreign minister in Tokyo had replied to the reports of Japanese officials in touch with the OSS operation in Switzerland. The Japanese official in Switzerland emphasized to Dulles' go-between, per Jacobsson, that he was hoping for a 'real response' from Tokyo within a week unless resistance was too great. Meanwhile, the Allies should not take "too seriously" what was said on Tokyo Radio concerning the Potsdam proclamation as this was merely "propaganda to maintain morale." The "real reply" would be transmitted through some "official channel," possibly the minister himself or General Okamoto in Switzerland.

Here again, we do not have much information. We do not know how Truman and his chief advisers felt about Donovan's report. On the surface it clearly reinforced other evidence--especially the cables indicating the emperor's strong initiative--of Japan's willingness to surrender, evidence we know the president had at the time.

I cite such points because nonspecialists often believe historians know and have reported the full Hiroshima story, and because I believe further caution is advisable with respect to the "ongoing assumption" theory of the bombing. The new evidence suggests that there may well have been full awareness that the bomb was not needed, and explicit consideration of it primarily in terms of its political role vis-a-vis the Soviet Union. And privately, between Truman and Byrnes, a conscious decision may have been taken.

A modified form of the ongoing-assumption theory can still be fitted to the presently known facts. But as one who put a version of it forward originally--with, I hope, adequate caveats--let me stress that it is no longer possible to rule out the likelihood that the president knew exactly what he was doing and made a clear decision with his closest adviser. Further historical discoveries may answer the remaining questions.