Four Days in May: Henry L. Stimson and the Decision to Use the Atomic Bomb
Sean L. Malloy
Among the myriad controversies surrounding the American use of nuclear weapons against Japanese cities in August 1945 is the seemingly simple question of exactly when President Harry S. Truman decided to use the bomb. The closest thing to a presidential directive regarding use was an order dispatched on July 25, 1945 from Acting Army Chief of Staff Thomas T. Handy to General Carl A. Spaatz, commander of the United States Army Strategy Air Forces. The directive, personally approved by Secretary of War Henry L. Stimson, authorized the delivery of the “first special bomb as soon as weather will permit visual bombing after about 3 August 1945. . .” The bomb was to be used on one of four target cities (a list that included Niigata and Kokura as well as Hiroshima and Nagasaki) and no further orders were required for the use of additional bombs, which were to be “delivered on the above targets as soon as made ready by the project staff.”  But while this directive was almost certainly discussed with the president before its approval, Truman never signed this or any other order with respect to the use of the atomic bomb against Japan. More significantly, the order was itself the product of an extended series of discussions and decisions that in some cases went back months or even years prior to the summer of 1945. While significant as a link in the chain of operations that culminated in the atomic bombings of August 6 and 9, historians must look beyond the July 25 directive to understand exactly when and how Truman committed to the use the bomb.
Piecing together when (and why) American leaders decided to use the bomb requires us to abandon the simplistic notion that Truman confronted a binary choice between use and non-use. There is no evidence that any high-level American authorities ever considered the question of whether to use the atomic bomb. The “A-bomb-or-invasion” binary that has so enraptured some historians was simply not a question that Truman (or Roosevelt for that matter) ever directly addressed. What American leaders did discuss extensively, and sometimes heatedly, were the questions associated with how, where and when to use the bomb. Should it be used against Germany or Japan? What targets within those countries might be appropriate for such a weapon? Should there be a warning or demonstration first? How might the bomb be integrated into American diplomacy with respect to both allies and enemies? What implications might its use have for the postwar period? Fully addressing this complicated series of choices is beyond the scope of this essay. Instead, I draw here from my larger work on Stimson and the A-bomb decision to explore two important questions that shaped the context of use: the integration of the bomb into a larger diplomatic strategy aimed at securing Japanese surrender and the choice of targets within Japan. Key decisions on both of these questions were made over a period of four days in Washington from May 28-31, 1945. In both cases, Secretary of War Stimson was an important (but by no means all-determining) figure.
Secretary of War Henry L. Stimson (with military aid Col. W. H. Kyle)
Born in 1867, only two years after the end of the American Civil War, Stimson had devoted much of his life to public service. A respected Republican statesman, he had a reputation for bipartisan service to his country. Prior to serving as secretary of war to Roosevelt and then Truman from 1940-1945, he had worked under Herbert Hoover as secretary of state and had been a presidential emissary to Nicaragua and governor general of the Philippines under Calvin Coolidge. His stint in the War Department from 1940-1945 was his second, having previously served as secretary of war under William Howard Taft. But while he had a long association with the military (one that included service as a fifty-year-old volunteer in the American Expeditionary Force during World War I), Stimson hated war. His fundamental conservatism, religious convictions, strong commitment to the rule of law (instilled by his mentor, the famous American lawyer and international jurist Elihu Root), and the sobering experience of World War I, led him to devote much of his career to preventing or at least containing the violence unleashed by war. He was particularly anxious to avoid violence against civilians. Thus while he strongly supported American entry into World War II as necessary to check the evil of a lawless Nazi regime, he simultaneously worried that the indiscriminate use of force in pursuit of victory would sow seeds of bitterness and hatred, undermining the foundations of any peace that followed. 
It was in the context of this overlapping set of military, diplomatic, and moral concerns that Stimson confronted the atomic bomb in the wake of the Nazi defeat in May 1945. Having been absorbed in the massive task of organizing victory in Europe, it was not until May 28, 1945, upon returning to Washington following a ten-day working vacation at his Long Island estate, that he felt prepared to tackle the issue that would dominate the remainder of his tenure in office. “I have made up my mind,” Stimson confided to his diary, “to make [the atomic bomb] my primary occupation for these next few months, relieving myself so far as possible from all routine matters in the Department.”
Decoupling the Diplomatic Track with Japan
The first of the overlapping A-bomb-related questions that Stimson confronted following his return to Washington on May 28 involved Japan. Prior to 1945, discussions about the diplomatic implications of nuclear fission had focused almost exclusively on the Soviet Union and Great Britain. Indeed, for most of the war, Stimson had paid comparatively little attention to the Pacific theater. In February 1945, following a meeting with Marshall on “the coming campaign against Japan,” Stimson conceded that “I have never studied it or thought over it in the way that I had over the war in Europe.” But starting in early 1945 and accelerating with the end of the war in Europe, Stimson and other American policymakers faced a decision on how to integrate the atomic bomb into their diplomatic and military calculations regarding Japan.
After the war, Stimson and other defenders of the A-bomb decision insisted that they had faced a stark choice between a costly invasion of the Japanese home islands and the use of the bomb against Japanese cities. In spring 1945, however, it was not certain that either an invasion or atomic bombs would be necessary to compel surrender. The Imperial Japanese Navy had virtually ceased to exist following the Battle of Leyte Gulf in October 1944. American submarines were strangling and isolating Japan’s home islands while Army Air Forces bombers gradually reduced its cities to ashes. Japan’s increasingly precipitous military decline did not necessarily mean that surrender was imminent. The brutal battle for Okinawa (the last stepping-stone on the path to the home islands) from April to Japan’s defeat on June 23, 1945, proved that Japanese resistance could still be quite fierce. But even as the fighting on that island raged, some in the Truman administration were pondering a combination of threats and promises that might hasten Japanese surrender and achieve vital American war aims through diplomatic means.
The stated policy of the Truman administration was that the United States would accept nothing less than Japan’s total and unconditional surrender. Truman had inherited this formula from Roosevelt, who had publicly proclaimed Allied war aims to include “an unconditional surrender by Germany, Italy and Japan” following a meeting with Churchill at Casablanca in January 1943. In practice, however, Roosevelt’s own record on unconditional surrender was mixed. While he had insisted on applying that formula to Nazi Germany, Italy had been allowed to negotiate terms in September 1943 that fell short of unconditional surrender. The question in spring 1945 was whether similar flexibility ought to be granted to Japan if doing so might expedite the end of the war and save American and Allied lives.
During a review of American military strategy in the Pacific on April 25, 1945, the Joint Chiefs of Staff (JCS) recommended that “‘unconditional surrender’ should be defined in terms understandable to the Japanese, who must be convinced that destruction or national suicide is not implied.” Several weeks later, Stimson received a “rather dramatic and radical” memorandum from his former boss, ex-president Herbert Hoover, warning that an invasion of Japan would be disastrous and suggesting that the United States should instead offer a clear set of surrender terms. Hoover's memorandum echoed ongoing discussions within the Army General Staff and the War Department's Operations Division (OPD) on clarifying or perhaps abandoning unconditional surrender. By the end of May, civilian leaders in both the War and State Departments, including Undersecretary of State Joseph Grew and Stimson deputy John J. McCloy, had determined to bring this question to the highest levels of the U.S. government.
When Stimson arrived back in Washington on May 28, McCloy presented him with a memorandum urging a reconsideration of the policy of unconditional surrender. McCloy asserted that “Japan is struggling to find a way out of the horrible mess she has got herself into” and urged that the United States avoid seeking to impose a “Carthaginian” peace. On the subject of unconditional surrender, McCloy conveyed his belief that the United States could likely “accomplish everything we want to accomplish in regard to Japan without the use of that term.” Failure to clarify and perhaps soften American terms might “hold them off to the point where we go on digging them out of caves at considerable cost to ourselves when our important objectives can be won without this attrition.”
On the same day, Grew (then acting as secretary of state while Edward Stettinius was attending the San Francisco Conference) suggested an even more specific change in U.S. policy. In a meeting with Truman, Grew, the former Ambassador to Japan, advised that the “greatest obstacle to unconditional surrender by the Japanese is their belief that this would entail the destruction or permanent removal of the Emperor and the institution of the Throne.” Grew understood that the institution of the emperor was the one unifying element of the Japanese political and military structure, “without which surrender will be highly unlikely.” Suggesting that a recent series of devastating attacks on Tokyo inflicted by American bombers offered a fortuitous moment to issue such a clarification, Grew pleaded for a statement guaranteeing the postwar status of the emperor. According to Grew's later account of the meeting, the president indicated that “his own thoughts had been following the same line” but asked the acting secretary to clear the proposal with Stimson, Army Chief of Staff Marshall, and Secretary of the Navy James V. Forrestal. The result was an informal conference of the president's chief military and diplomatic advisers in Stimson's Pentagon office on May 29, 1945.
Stimson, motivated by a desire to end the war quickly and entirely uninterested in dictating the form of the postwar Japanese government, was sympathetic to calls for modifying American surrender terms. From the outset of American participation in the conflict, he had sought to balance the goal of “complete victory” with that of shortening the war and thus reducing both the loss of life and the burden of reconstruction that would face the victorious Allies. And though he had insisted on the importance of Germany's unconditional surrender, the secretary of war eagerly embraced compromises far short of that formula when it came to Hitler's partners and vassals.
The first example of Stimson's flexibility on surrender terms came early in the war, prior to the public formulation of the unconditional surrender doctrine. During the course of the November 1942 landings in North Africa, Stimson strongly supported the deal struck by General Dwight D. Eisenhower with Admiral Jean Francois Darlan, commander-in-chief of the Vichy military forces. The so-called Darlan deal, under which the former Vichy commander was granted political authority over French North Africa in exchange for an agreement not to oppose the American landings, produced howls of outrage in the United States and Great Britain. To Stimson, however, the Darlan deal accurately reflected the priorities of the Allied war effort. Germany, not Vichy France, was the main enemy, and continental Europe, not North Africa, was the important theater of operations. The secretary of war supported the Darlan deal as a way to save American lives and hasten the end of the war.
Even after Roosevelt publicly proclaimed the unconditional surrender formula, the secretary of war was still eager to seek compromise outside the special case of Nazi Germany if it might shorten the war. Stimson repeatedly warned Roosevelt regarding what he laconically referred to as the danger of “too much unconditional surrender on Italy.” That nation posed little military threat by itself, and “the people of the United States,” Stimson observed, were not “interested the least little bit in taking a great part in the politics of Italy.” During the secret negotiations between American representatives and Italian Marshall Pietro Badoglio, the secretary of war repeatedly voiced support for a deal that allowed Italy a conditional surrender.
Stimson’s willingness to compromise with Italy and Vichy France reflected his judgment that the pursuit of victory needed to be tempered with an appreciation of the dangers of prolonged warfare to the fragile foundations of what he termed “industrial civilization” around the world. The secretary of war approached the problem of Japan in general and the emperor in particular with the same calculation in mind. Following any surrender, the United States would have to disarm Japan’s military and seize many of its former bases in the Pacific in order to guard against any future acts of aggression. Beyond those basic requirements, he saw no need to engage in the sort of extensive reconstruction and rehabilitation that the Allies were implementing in occupied Germany. Stimson had never at any point in his career believed that the elimination of the emperor or the emperor system was necessary to check Japanese militarism. In the dying days of the war in the Pacific, he explicitly opposed any attempts to remake “the government of [Japan] as a whole in any such manner as we are committed in Germany. I am afraid we would make a hash of it if we tried.”
At the meeting on May 29 including Marshall, Forrestal, Grew, and State Department Far East expert Eugene Dooman, Stimson “was inclined to agree with giving the Japanese a modification of the unconditional surrender formula without the use of those words.” He indicated, however, that “the timing was wrong and this was not the time to do it,” a sentiment with which Marshall voiced agreement. Stimson and Marshall's opposition carried the day, and the meeting adjourned without any further action taken on the question of surrender terms for Japan. This delay turned out to be highly significant in shaping the context of the bomb’s use. Deliberations on surrender terms continued sporadically in the aftermath of this meeting, but by tabling the issue until an unspecified later date, Stimson and Marshall had decoupled the diplomatic track from discussion about the use of the atomic bomb at a crucial moment. In May-June 1945, American leaders made important decisions about both the use of the bomb and the invasion of the Japanese home islands without ever pausing to consider their minimum acceptable definition of victory.
Why did the secretary of war advise a delay in considering a modification of American surrender terms in May 1945? It was not any newfound commitment to the principle of unconditional surrender. The day after the May 29 meeting, Stimson wrote to Marshall and explicitly endorsed McCloy's suggestion that the United States should back away from insisting on an unconditional Japanese surrender. In the weeks that followed, Stimson explicitly spoke in favor of allowing the Japanese to retain the emperor. Why, then, did he counsel delay at the crucial meeting on May 29?
Grew's account of the reasoning reason behind this delay was cryptic, recording simply that “for certain military reasons, not divulged, it was considered inadvisable for the President to make a statement just now.” Stimson later claimed that he favored a delay because “we were having considerable trouble with the Japanese in the land campaign on Okinawa and some of us were afraid that any public concession at that time might have been taken as an indication of weakness.” But none of the contemporary accounts of the May 29 meeting, including Stimson’s diary, mention the fighting on Okinawa as a reason for delaying a restatement of American terms. Instead we have a vague reference (in Grew’s diary) to “certain military reasons, not divulged.” There was nothing secretive about the ongoing fighting on Okinawa and hence no reason for either Stimson or Marshall to offer such an elliptical response if this had been their primary concern. Moreover, even if such fears had made Stimson and Marshall hesitate to issue an immediate public statement on the emperor, there was no reason not to reach an internal consensus on the issue, agreeing on a revised set of terms that Truman could present when the time and tide of battle appeared fortuitous.
After the war, Grew and several of his former State Department colleagues were still frustrated and puzzled by the outcome of the May 29 meeting on surrender terms. Dooman privately blasted Stimson's postwar explanations for the delay, characterizing them as “disingenuous” and “sinister.” After a discussion with Grew in 1947, former State Department official William R. Castle (who had worked under Stimson in the Hoover administration) confided his own suspicions: “I wonder whether Stimson, with Marshall, wanted the [the] war to continue long enough to give them a chance to try out the atom bomb on Japanese cities. The more I think of that performance the more I feel that it was indefensible as well as brutal.” Hoover, without directly commenting on Stimson’s role in the process, privately confided that “[t]he use of the Atomic bomb, with its indiscriminate killing of women and children, revolts my soul.” But while neither Grew, Castle, nor Hoover had any way of knowing it, Stimson was, in fact, far from eager to use the bomb and ultimately made a last-ditch effort behind the scenes to secure surrender without the use of this terrible new weapon.
The real explanation for Stimson’s seemingly curious performance on May 29 was his continuing uncertainty over how, exactly, to integrate the atomic bomb into American diplomacy. “It was an awkward meeting,” the secretary of war confided in his diary, “because there were people present in the presence of whom I could not discuss the real feature which would govern the whole situation, namely S-1 [the atomic bomb].” Preoccupied with a wide range of issues relating to the use of the bomb and the shape of the postwar world, Stimson assumed that a formal decision on clarifying and perhaps softening surrender terms could wait until the bomb was closer to readiness. Once the bomb was tested and ready for use, he would presumably have a better idea of how to integrate this new weapon with diplomatic approaches to Japan.
According to McCloy, the secretary understood that the May 29 decision to delay a restatement of American terms “only postponed consideration of the matter for a time . . . for we shall have to consider it again preparatory to the employment of S-1.” What Stimson did not appreciate was how difficult it would be to revisit the diplomatic track with Japan after the technical and military decisions about how to use the bomb were made in the days that followed the May 29 meeting. Ultimately, delay would contribute to a tragedy that the secretary of war would later regret.
“The Targets Suggested . . . Have Been Disapproved”
Having decided to temporarily table consideration of surrender terms on May 29, Stimson and Marshall dismissed the rest of the group while they stayed behind (with McCloy taking notes) to discuss more practical matters related to the use of the bomb. In considering “Japan and what we should do in regard to S-1 and the application of it,” Stimson and Marshall returned to a set of questions about use of the bomb that they had deferred in the early years of the American nuclear project. One of the subjects they discussed that afternoon was nuclear targeting and the mass killing of Japanese civilians.
Stimson was acutely sensitive to the dangers of indiscriminate force in the pursuit of victory and consistently objected to the intentional killing of civilians. With respect to the atomic bomb, however, Stimson had joined Roosevelt in embracing its wartime development while deferring potential difficult questions about its use (including the question of targets) until the project was closer to fruition. As a result, discussions of nuclear targeting prior to May 1945 had been almost entirely confined to the scientists and engineers at Los Alamos in concert with a handful of lower-level AAF officers. Driven by technical concerns, work at Los Alamos had gradually coalesced around a weapon optimized for use against cities and civilians. By December 1944, the only question so far as Los Alamos Ordnance Division chief William Parsons was concerned was which Japanese city would be destroyed first. Beginning in late January 1945, AAF and Los Alamos personnel met with increasing frequency to discuss operational issues relating to the use of the atomic bomb, including the question of targeting. These meetings culminated in April with the formation of a group known as the Target Committee that included representatives from both Los Alamos and the AAF.
The first Target Committee meeting on April 27, 1945, officially ratified the strategy of city targeting that had evolved from the work of Los Alamos and the Ordnance Division. The committee decided that in picking a target they should focus on “large urban areas of not less than 3 miles in diameter existing in the larger populated areas.” At a second series of meetings on May 10-11 in Oppenheimer's Los Alamos office, the Target Committee formally rejected the idea of attacking an isolated military target, concluding that “any small and strictly military objective should be located in a much larger area subject to blast damage in order to avoid undue risks of the weapon being lost due to bad placing of the bomb.” Operating under the same assumptions that had guided the research and development of the weapon as at Los Alamos, the AAF officers involved in selecting A-bomb targets understood the bomb primarily as a large blast weapon. This logic, along with concerns over the ability of AAF planes to accurately deliver the weapon, led the committee to almost exactly reprise Parsons's earlier recommendations. The bomb would be used in a large urban area where it would be sure to destroy large numbers of lightly constructed buildings and in the process kill many Japanese civilians.
Concerns about maximizing the bomb's blast effects also dictated another recommendation that emerged from the Target Committee: that it should be used against a relatively undamaged city. The first meeting of the Target Committee rated Tokyo low on the target list because it was “now practically all bombed and burned out.” This inconvenient fact meant that Tokyo and other previously attacked Japanese cities lacked the abundance of light, undamaged residential and industrial structures that were the ideal targets for the bomb’s blast effects. Unconcerned or uninterested in effects produced by fire and radiation, the Target Committee decided that using the bomb against either a military target or an already damaged Japanese city would waste the bomb’s blast effects and produce disappointing results.
The third and final meeting of the Target Committee on May 28, 1945, culminated in the selection of Kyoto, Hiroshima, and Niigata as targets for the atomic bomb. All three cities harbored important Japanese war industries. However, in all these cities the most significant military-industrial targets were located on the fringes of the larger urban area. Targeting these war plants risked the possibility that an inaccurate delivery might result in the bomb’s exploding entirely outside the city. Moreover, even an accurate attack on one of these factories would fail to make use of the full power of the bomb as there were fewer light structures susceptible to blast on the urban fringes than in the city center. The meeting concluded with the Target Committee members’ agreeing to a set of recommendations that explicitly endorsed targeting densely populated urban areas at the expense of any effort to hit military-industrial targets:
"[The Target Committee agreed] not to specify aiming points, this is to be left to later determination at base when weather conditions are known.
to neglect location of industrial areas as pin point target, since on these three targets [Kyoto, Hiroshima, and Niigata] such areas are small, spread on fringes of cites and quite dispersed.
to endeavor to place the first gadget in center of selected city; that is, not to allow for later 1 or 2 gadgets for complete destruction."
This was a recommendation to use the bomb as a weapon for the obliteration of cities and the mass killing of civilians. And while targeting the atomic bombs in the center of Kyoto, Hiroshima, and Niigata ensured that some smaller, scattered military-industrial targets would be destroyed, it also virtually guaranteed that the most significant war industries associated with those three cities would be spared any significant damage.
Stimson and Marshall were unaware of the Target Committee's recommendations when they discussed the bomb in the secretary of war’s office on May 29. Unlike the approach of Parsons and the Target Committee, Stimson’s thinking about the bomb went well beyond technical efficiency. Civilian casualties were a regrettable but inevitable part of modern warfare. But to deliberately target civilians for mass killing not only was immoral but, by harming the international reputation of the United States, might undermine American leadership in the postwar world. Declaring that the “reputation of the United States for fair play and humanitarianism is the world’s biggest asset for peace in the coming decades,” Stimson repeatedly stressed that he was “anxious to hold our Air Force, so far as possible, to the `precision' bombing which it has done so well in Europe.” In a discussion with Truman on May 16, 1945, he explicitly linked his concerns over strategic bombing to the use of the atomic bomb, suggesting that “the same rules of sparing the civilian population should be applied as far as possible to the use of any new weapons.”
In a telephone conversation with McCloy on May 21, Stimson and his assistant secretary discussed the question of the “big bomb” and “when it should be employed and how” with specific reference to “the moral position of the United States and its responsibilities.” Recounting this conversation, McCloy confided to his diary “the moral position of the U.S. weighs greatly upon [Stimson]” with respect to the use of the bomb. Reflecting the concerns of the secretary of war, an outline for a presidential statement prepared by Stimson’s aides on May 25 and intended for release after the use of the bomb stressed that the United States would “[c]hoose a military target like a naval base if possible so that wholesale killing of civilians will be on the heads of the Japanese who refused to surrender at our ultimatum.”
Concerns over the targeting of civilians surfaced again during the discussion between Marshall and Stimson on May 29. “The Secretary,” McCloy noted in a memorandum summarizing the discussion, “referred to the burning of Tokyo and the possible ways and means of employing the larger bombs.” In the context of Stimson’s concerns about indiscriminate incendiary attacks against Tokyo, expressed both before and immediately after the May 29 meeting, this statement suggests that Stimson was troubled by the idea of using the atomic bomb against a primarily civilian target. In response to Stimson’s comments, Marshall offered an explicit argument against using the atomic bomb against civilians:
"General Marshall said he thought 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, he thought 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. . . . Every effort should be made to keep our record of warning clear. We must offset by such warning methods the opprobrium which might follow from an ill considered employment of such force."
Marshall’s statement, with its emphasis on limiting the conduct of war against civilians and its attention to the international reputation of the United States, mirrored Stimson's long-held concerns on this subject. These intertwined moral and practical concerns sharply diverged from the recommendation of the Target Committee, with its emphasis on the total destruction of Japanese urban areas. The next day, these divergent approaches to nuclear targeting collided in the secretary of war's Pentagon office.
Army Chief of Staff General George C. Marshall
At 9:20 a.m. on May 30, Harvey Bundy placed a call to General Leslie Groves to inform him that the secretary wanted to see him “right away.” When the general arrived at the Pentagon, he found that Stimson was intent on discussing the question of nuclear targeting. Groves had planned to submit the recommendations of the Target Committee directly to the army chief of staff at a later date and attempted to deflect Stimson's questions by declaring that “I would rather not show [the report] to him without having first discussed it with General Marshall.” Stimson, according to Groves’s later account, reacted sharply to this attempted diversion: “Mr. Stimson said: ‘This is one time I'm going to be the final deciding authority. Nobody's going to tell me what to do on this. On this matter I am the kingpin and you might just as well get that report over here.’” While Stimson waited for Groves's staff to fetch the Target Committee's recommendations from his office across the Potomac, the secretary summoned Marshall to join them in a discussion of nuclear targeting.
Stimson's diary is elliptical in its description of the events of that morning, recording simply that “[w]e talked over the subject very thoroughly of how we should use this implement in respect to Japan.” Groves's postwar memoir described the ensuing debate as focused primarily on the targeting of Kyoto. Stimson had visited that city in the 1920s while traveling to the Philippines. Citing Kyoto's status as Japan's intellectual and cultural capital, Stimson objected to its inclusion as a target and cited his belief that the targeting decision “should be governed by the historical position that the United States would occupy after the war. He felt very strongly that anything that would tend in any way to damage this position would be unfortunate.” Stimson's concern with attacks on Kyoto (either conventional or nuclear) has been well documented. It seems unlikely, however, that Kyoto was the only subject of conversation that morning. The underlying logic of the Target Committee's recommendation, with its narrow emphasis on technical factors and its endorsement of the deliberate destruction of an entire city, sharply contrasted with Stimson's thinking about the conduct of the war as well as Marshall's explicit suggestion that a military target should be given first priority.
Lauris Norstad (left), Henry “Hap” Arnold (center), and Marshall (right) at the Potsdam Conference
A memorandum from Groves to Lauris Norstad, chief of staff of the Twentieth Air Force, written immediately after the May 30 meeting in Stimson's office, suggests that a larger controversy was brewing at the end of May 1945. “Will you please inform General Arnold,” Groves wrote to Norstad, “that this AM the Secretary of War and the Chief of Staff did not approve the three targets we had selected, particularly Kyoto.” The mention of Kyoto supports at least part of Groves's post facto account of the meeting. Yet the reference to "the three targets we had selected" suggests that Stimson and Marshall raised objections that went beyond the targeting of Kyoto. When Norstad informed AAF Chief of Staff Henry Arnold of the decision, he omitted mention of Kyoto entirely, noting simply that “targets suggested by General Groves for 509th Composite Group have been disapproved, supposedly by the Secretary of War.” Stimson's belated intervention threw into doubt the entire question of nuclear targeting on the eve of the May 31 meeting of the so-called Interim Committee.
May 31: Setting the Context of Use
The scattered and sometimes intense discussions in late May on the various questions that would determine the context of the bomb’s use culminated in a meeting of the Interim Committee on May 31, 1945. At 10:00 a.m., Stimson, Marshall, Groves, the regular members of the Interim Committee, and the newly created Scientific Advisory Panel, including physicists J. Robert Oppenheimer, Enrico Fermi, Arthur H. Compton, and Ernest O. Lawrence, assembled in the secretary of war’s Pentagon office. Stimson opened the meeting by declaring that “this project should not be considered simply in terms of military weapons, but as a new relationship of man to the universe.” He went on to warn that the bomb “must be controlled if possible to make it an assurance of future peace rather than a menace to civilization.” If not, it might become “a Frankenstein which would eat us up.”
Most of the morning discussion dealt with postwar issues, including the question of whether (and on what terms) the U.S. should discuss atomic energy with the Soviet Union. During an afternoon lunch break, at which time Marshall left to attend to other business, the committee informally discussed a noncombat demonstration of the bomb designed to impress the Japanese with the danger they faced. Oppenheimer had already voiced his opposition to a noncombat demonstration and apparently did so again at the May 31 meeting. According to Lawrence, Oppenheimer and Groves joined in asserting that “the only way to put on a demonstration would be to attack a real target of built-up structures.” In advocating the use of the bomb in such a way as to maximize its blast effects against light structures, the two men were following the same logic that had guided development of the weapon at Los Alamos. In the face of this skepticism about the chances of an effective noncombat demonstration, the conversation spilled over into the start of an afternoon session that began with “much discussion concerning various types of targets and the effects to be produced.”
The Interim Committee minutes offer limited insight into the nature of the debate over nuclear targeting, merely recording that eventually the secretary of war offered a conclusion with which the rest of the group expressed “general agreement.” Though insisting that “we could not concentrate on a civilian area,” Stimson apparently joined in the consensus that an isolated target or military base would not allow for a suitably dramatic demonstration of the bomb's power. In order “to make a profound psychological impression on as many of the inhabitants as possible,” the bomb would have to be used in an area where there were a large number of civilians to witness its effects. This recommendation ruled out both a noncombat demonstration and the use of the bomb against a strictly military target. It was agreed, following Conant's suggestion, that the best target would be “a vital war plant employing a large number of workers and closely surrounded by workers' houses.” No warning would be given to the Japanese prior to combat use.
While the notion of using the bomb against a “war plant” may have soothed the consciences of those with qualms over the targeting of noncombatants, the course of action they were recommending entailed as a basic requirement the mass killing of Japanese civilians. Why did Stimson agree to this recommendation? His long-held moral and practical concern with limiting the conduct of war and the record of his thoughts and actions in the days prior to the meeting both indicated a fundamental revulsion at the idea of using such a devastating weapon without warning against a predominantly civilian target, a sentiment shared by Marshall (who was not present for the afternoon discussion of targeting). The frustratingly opaque nature of the official minutes of the May 31 meeting makes it impossible to determine why the secretary of war ultimately acquiesced in the decision to target Japanese cities and civilians. It is, however, possible to offer several plausible conjectures.
Perhaps the most important limiting factor in the May 31 discussion of targeting was the type of weapon that Los Alamos was on the verge of producing. From 1944 onward, Los Alamos scientists and engineers had been working on a bomb designed to destroy the kinds of light structures found in abundance in Japanese cities. It was a concern with maximizing the destructive effects of the type of weapon produced by Los Alamos that had led the Target Committee to recommend using “the first gadget in center of selected city” at their final meeting on May 28. Though Stimson and some others on the Interim Committee were troubled by city targeting, as were some scientists connected to the Manhattan Project, their reservations could not change the fact that the bomb as designed was optimized for the destruction of cities and civilians. Given the time and money spent developing the bomb, the ongoing war in the Pacific, and the fact that Groves, Oppenheimer, and the Target Committee all endorsed use against a city, it is likely that Stimson saw the kind of mixed civilian and military-industrial target suggested by Conant, combined with the removal of Kyoto from the target list, as a lamentable but ultimately acceptable compromise.
Post-strike targeting photograph of Hiroshima
Another explanation for Stimson's decision to support the use of the bomb against Japanese cities was the so-called shock factor. In an influential article on the A-bomb decision published in Harper's under Stimson’s name in 1947, he directly linked the decision to use the bomb without warning on Japanese cities to the need to produce “the kind of shock on the Japanese ruling oligarchy which we desired.” The shock factor appears to have played an important but ultimately superficial role in the May 31 deliberations. Despite the loose talk of making a “profound psychological impression” on the Japanese, there does not appear to have been any discussion about calibrating the use of the bomb to achieve specific diplomatic objectives. Without an overall agreement on a diplomatic approach to Japan, including the issue of surrender terms, and without any experts on Japan present at the Interim Committee meetings, such a discussion was simply not possible. As Oppenheimer later put it, “We didn't know beans about the military situation in Japan.” Rather, the Interim Committee's discussion of the shock factor on May 31 appears to have focused not on “the Japanese ruling oligarchy” but rather on the effect that the bomb might have on Japanese civilians. This approach echoed a similarly superficial discussion of the psychological effects of the bomb during the course of the Target Committee's meetings at Los Alamos on May 11-12.
Technical concerns over the delivery and efficacy of the bomb had already dictated the choice of Japanese cities as targets by late 1944. It was in picking which city to attack that psychological factors came into play. The Target Committee ultimately selected Kyoto, the intellectual center and historical capital of Japan, as the best initial target in part because its inhabitants were “more highly intelligent and hence better able to appreciate the significance of the weapon.” The goal was not simply to obtain "the greatest psychological effect against Japan" but also to make “the initial use sufficiently spectacular for the importance of the weapon to be internationally recognized.” The Target Committee apparently left unexamined the question of how incinerating and terrorizing the “highly intelligent” citizens of Kyoto might push the Japanese government into capitulation. This macabre and shallow reasoning was reflective of a greater disconnect between the planning for military operations against Japan and the diplomatic efforts to leverage military success into a Japanese surrender that characterized the last months of the war in the Pacific.
On May 31 the Interim Committee apparently embraced the Target Committee's ill-defined formulation of the bomb as a psychological weapon. The desire to make “a profound psychological impression on as many of the inhabitants as possible’” clearly helped to justify the use of the bomb against cities and civilians. But as with the Target Committee's deliberations, there is no evidence that Stimson or any of the other Interim Committee members wrestled with the practical question of how the mass killing of civilians with atomic weapons might bring the Japanese government to surrender. At the May 31 meeting, the technical details of the bomb's use remained almost entirely divorced from the important diplomatic question of how -- and on what terms -- to end the war in the Pacific.
The ongoing conventional bombing of Japan also likely played a role in helping to validate the strategy of city targeting with nuclear weapons. The decisions at Los Alamos that had led to the design of a bomb optimized for use against cities and civilians were both independent of and predated the violent incendiary campaign against Japan begun by the AAF in March 1945. But in struggling with the question of what to do with this new weapon, the precedent set by conventional attacks on Tokyo and other Japanese cities almost certainly made it easier for the Interim Committee to consider using the weapon in the way envisioned by Parsons and the Target Committee.
A combination of self-deception and misleading information with respect to the nature of the target probably helped to seal Stimson's assent to the May 31 targeting recommendations. The self-deception came in the form of his willingness to accept that a “vital war plant employing a large number of workers and closely surrounded by workers’ houses” constituted a primarily military target. Stimson's self-deception was facilitated by Groves, who apparently withheld information about the targeting of the weapon at the May 31 meeting and in subsequent discussions prior to use. At the Target Committee meeting on May 28, it had been explicitly decided “not to specify aiming points” and “to neglect location of industrial areas as pin point target, since on these three targets, such areas are small, spread on fringes of cities and quite dispersed.” The 509th Composite Bomb Group subsequently adopted the Target Committee's recommendation in planning the strikes of August 6 and 9. Air crews at the 509th’s forward base on the island of Tinian were allowed to select their own aiming points in order to maximize the bomb's effect on the city as a whole at the expense of hitting any particular military-industrial target. Groves, however, did not correct either Stimson or Conant on May 31 (or later) when they suggested that the bomb would be employed against a specific military-industrial target rather than used in a deliberate attempt to annihilate an entire city.
The difference between the Interim Committee's May 31 recommendation on targeting and that offered by the Target Committee (and subsequently followed by the 509th in the attacks on Hiroshima and Nagasaki) was in some ways minor. Both accepted use against a city; the only difference was the aim point within the city. But to Stimson this point was likely important in that it allowed him to believe that he was not intentionally targeting civilians for mass killing. Moreover, as events at Nagasaki would later reveal, the seemingly academic question of aim points had real life-and-death significance for the bomb's potential victims.
“Outdoing Hitler in Atrocities”
Events proceeded rapidly following the conclusion of the marathon meeting of the Interim Committee on May 31, which served as the capstone to four days in which the pivotal issues of sometimes heated discussion related to unconditional surrender and nuclear targeting. On June 6, Stimson met with Truman to present the committee’s recommendations. By this point, prior to both Truman's approval of the plan to invade Japan and the meeting at Potsdam that culminated in the final American ultimatum to the Japanese government, the top political, military, and scientific figures involved in the Manhattan Project had already signaled their assent to a set of policy guidelines that would determine the use of the bomb. The United State would use nuclear weapons on Japanese cities. There would be no prior public statement or warning to Japan about the bomb. Nor would there be any attempt to enter into negotiations with the Soviet Union about postwar international control of atomic energy prior to combat use.
As he presented these recommendations to the president, Stimson exhibited a seemingly schizophrenic attitude toward the moral issues involved. In the course of the June 6 meeting, the secretary of war again raised his objections to the conventional area bombing of Japanese cities, stating his desire “to hold the Air Force down to precision bombing” if possible. Stimson offered two reasons for opposing indiscriminate attacks on Japanese cities:
"[F]irst, because I did not want to have the United States get the reputation of outdoing Hitler in atrocities; and second, I was a little fearful that before we could get ready the Air Force might have Japan so thoroughly bombed out that the new weapon would not have a fair background to show its strength."
In his linkage of American area bombing to Nazi atrocities, Stimson was expressing long-held concerns about the need to restrain the conduct of the war for both practical and moral reasons. This concern was fresh in the secretary of war's mind -- he had recently heard chilling private testimony from a congressional committee that had investigated Nazi war crimes in Europe, including the notorious death camps at Dachau and Buchenwald. Yet after initially raising objections to city targeting with either conventional or nuclear weapons, Stimson was now apparently willing to sanction the use of indiscriminate force against Japanese civilians in the form of the atomic bomb. In response to his secretary of war's tortured logic, Truman “laughed and said he understood.”
Presented with a two billion-dollar weapon designed for the destruction of cities, Stimson undoubtedly hoped that, however terrible, the bomb might speed the end of the war and obviate further bombing as well as the planned invasion of the Japanese home islands. Oppenheimer's rejection of a noncombat demonstration and the combination of deception and self-deception on the types of targets to be hit likely helped him to rationalize the course of action that he recommended to Truman on June 6. Ultimately, however, the position of endorsing indiscriminate nuclear killing in order to end indiscriminate conventional killing proved to be an uncomfortable one for the secretary of war. For the next two months, Stimson and others privy to the atomic secret continued to explore alternatives even as preparations for use of the bomb against Japanese cities went forward.
By early July, Stimson belatedly acted on the advice of Grew and others, suggesting to Truman that any future statement to Japan should include the reassurance that “we do not exclude a constitutional monarchy under her present dynasty.” At the Potsdam Conference in mid-July (which he attended as an informal advisor to Truman), the secretary of war urged the president to issue a clarification of American terms, including a statement on the Emperor, prior to the use of the bomb. If the Japanese continued to resist after such a clarification, then, and only then, “the full force of our newer weapons should be brought to bear” along with “a renewed and even heavier warning, backed by the power of the new forces and possibly the actual entrance of the Russians in the war.” Apparently frustrated when Truman and Secretary of State James F. Byrnes refused to consider issuing a statement on the Emperor as part of the July 26 Potsdam Declaration, Stimson also sought to revisit the targeting issue. In a series of conversations with AAF Chief of Staff Arnold at Potsdam, Stimson discussed the bomb’s effects on “surrounding communities” and “the killing of women and children.”
Stimson and Secretary of State James F. Byrnes at Potsdam.
The last-minute American deliberations about the bomb and surrender terms at Potsdam have been the subject of intense academic study and much controversy. But while Truman and Byrnes have borne the brunt of the criticism for their failure to offer a clear statement of the postwar status of the emperor at Potsdam, Stimson and Marshall also played an important (if inadvertent) role in determining this outcome. By temporarily tabling any reconsideration of American surrender terms several months earlier at the May 29 meeting, the secretary of war and army chief of staff forfeited what was almost certainly the best opportunity to join the diplomatic track with discussions over the use of the bomb. The hectic, tension-filled atmosphere of the Potsdam Conference proved to be an inauspicious place for a reasoned discussion of the unconditional surrender issue. The same could be said of the targeting issue. If the intransigence of Japanese leaders, abetted by the American delay in clarifying surrender terms, ultimately made the use of the bomb inevitable, it did not necessarily follow that it had to be used without warning against cities and civilians. But once again Potsdam proved to be a poor venue in which to belatedly revisit the complicated technical and operational issues related to nuclear targeting. Though Stimson (with Truman’s assent) did manage to keep Kyoto off the targeting list, his ruminations on “the killing of women and children” were not enough to overcome the momentum toward city targeting that began at Los Alamos and was ratified by the Target Committee and Interim Committee in late May.
Aerial view of Hiroshima after the bombing.
None of the evidence or arguments above should be taken to imply that all the important choices about use were finalized by May 31. But the accretion of previous decisions, taken either consciously or as a result of simple inaction or inattention on the part of the relevant policy makers, made last minute reconsideration of issues such as surrender terms and targeting difficult even under the best of circumstances. The sheer number of issues under consideration at Potsdam and the time pressure associated with the ongoing fighting with Japan, imminent Soviet entry into the Pacific War, and the looming disputes over the postwar settlement, made such reconsideration next to impossible. In that respect, unraveling the atomic bomb “decision” requires a close engagement with the series of technical, political, military, and diplomatic decisions that worked to gradually shape the context of use long before the Enola Gay left on its fateful mission in August 1945.
Sean L. Malloy is an assistant professor of history at the University of California, Merced and the author of Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan. This is a revised and expanded version of a chapter of Atomic Tragedy.
Reprinted material from “The Ordeal of Henry L. Stimson,” in Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb against Japan,” by Sean L. Malloy. Copyright © 2008 by Cornell University. Used by permission of the publisher, Cornell University Press.
Posted at The Asia-Pacific Journal on April 4, 2009.
Recommended citation: Sean L. Malloy, “Four Days in May: Henry L. Stimson and the Decision to Use the Atomic Bomb” The Asia Pacific Journal, Vol. 14-2-09, April 4, 2009.
 Acting Chief of Staff Thomas T. Handy to General Carl A. Spaatz, July 25, 1945, Carl A. Spaatz Papers, Library of Congress, box 24, “July, 1945.”
 On Stimson and his complicated relationship to the bomb see Sean L. Malloy, Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan (Ithaca, 2008). Other biographical treatments of Stimson include David Schmitz, Henry L. Stimson: The First Wise Man (Wilmington, Del., 2001); Godfrey Hodgson The Colonel: The Life and Wars of Henry Stimson, 1867-1950 (New York, 1990); Elting Elmore Morison, Turmoil and Tradition: A Study of the Life and Times of Henry L. Stimson (Boston, 1960). Henry Lewis Stimson Diaries (microfilm edition), Manuscripts and Archives, Yale University Library (hereafter cited as Stimson Diary), May 28, 1945.
 Stimson Diary, February 27, 1945.
 Though its focus is split between the USSR, Japan, and the United States, Tsuyoshi Hasegawa's Racing the Enemy: Stalin, Truman, and the Surrender of Japan (Cambridge, Mass., 2005) is probably the best single source on the debate within the American government over surrender terms in 1945. Also see Richard B. Frank, Downfall: The End of the Imperial Japanese Empire (New York, 1999), 214-21.
 The original and most influential statement of this orthodox defense of the bomb was Stimson, “The Decision to Use the Atomic Bomb,” Harper’s (February 1947): 97-107. For more contemporary restatements of this position see Robert James Maddox, Weapons for Victory: The Hiroshima Decision (Columbia, Mo., 2004); Robert Newman, Truman and the Hiroshima Cult (East Lansing, Mich., 1995).
 Foreign Relations of the United States, The Conferences at Washington, 1941-1942, and Casablanca, 1943, (Washington, D.C.) 837 (hereafter cited as FRUS).
 Joint Chiefs of Staff 924/15, April 25, 1945, box 169, section 12, record group 218, National Archives II, College Park, MD.
 Herbert Hoover Memorandum, May 15, 1945, Formerly Top Secret Correspondence of Secretary of War Stimson, record group 107, box 8, National Archives II, College Park, MD. (hereafter cited as “Safe File”); Stimson Diary, May 16, 1945.
 McCloy, “Memorandum for Colonel Stimson,” May, 28, 1945, “Safe File,” box 8.
 Grew, “Memorandum of Conversation with the President,” May 28, 1945, enclosed in Grew to Stimson, February 12, 1947, Henry Lewis Stimson Papers (microfilm ed.), reel 116, Manuscripts and Archives, Yale University Library, (hereafter cited as Stimson Papers).
 Joseph Grew to Stimson, February 12, 1947, Stimson Papers, reel 116.
 Stimson to Roosevelt, March 15, 1944, Stimson Papers, reel 109.
 Stimson Diary, November 18, 1942; David M. Kennedy, Freedom from Fear: The American People in Depression and War, 1929-1945 (New York, 1999), 582-83; Robert Dallek, Franklin D. Roosevelt and American Foreign Policy 1932-1945 (New York, 1979), 364-66.
 Stimson Diary, June 14 (“politics of Italy”), July 1(“too much unconditional surrender”), 1943. Also see Stimson to Roosevelt, September 20, 1943, Stimson Diary.
 Stimson, “Memorandum for the President: The Conduct of the War with Japan,” enclosed in Stimson to James F. Byrnes, July 16, 1945, Stimson Papers, reel 113.
 Others present included the director of the Office of War Information (OWI), Elmer Davis, and Judge Samuel Rosenman, counsel to the president. Stimson Diary, May 29, 1945; Forrestal Diary, May 29, 1945.
 Stimson, “Memorandum for the Chief of Staff,” May 30, 1945, “Safe File,” box 8.
 Grew Diary, May 29, 1945, reprinted in Grew, Turbulent Era: A Diplomatic Record of Forty Years, 1904-1945 (Cambridge, Mass., 1952), 1434.
 Stimson to Joseph Grew, June 19, 1947, Eugene H. Dooman Papers, box 2, Hoover Institution Archives, Stanford, Calif. (hereafter cited as Dooman Papers).
 Grew, Turbulent Era, 1434.
 Eugene Dooman to Joseph Grew, June 30, 1947, Dooman Papers, box 2.
 February 9, 1947, The Diary of William R. Castle (microfilm of original), Houghton Library, Harvard University.
 Herbert Hoover to John C. Laughlin, August 8, 1945, Hebert Hoover Presidential Library, West Branch, Iowa, Post-Presidential Individual File, “O’Laughlin, John C.” On Stimson’s last minute efforts at Potsdam to facilitate a Japanese surrender prior to the use of the bomb see Malloy, Atomic Tragedy, 121-32.
 Stimson Diary, May 29, 1945.
 John J. McCloy, "Memorandum of Conversation with General Marshall May 29, 1945, 11:45 AM," “Safe File,” box 12.
 Stimson Diary, May 29, 1945. For a lengthy discussion of nuclear targeting in World War II, see Sean L. Malloy, “‘The Rules of Civilized Warfare’: Scientists, Soldiers, and American Nuclear Targeting, 1940-1945,” The Journal of Strategic Studies, Vol. 30, No. 3, 474-512.
 Malloy, Atomic Tragedy, 49-65.
 “Character and strength of buildings in different parts of the city” and the “Contour of the ground” were the factors that Parsons suggested would be most important in selecting cities for destruction. William Parsons to William Purnell (via Leslie Groves), December 12, 1944, Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-46, microfilm publication M1109, file 5D, National Archives (hereafter cited as Groves “Top Secret”).
 AAF Target Committee members were Brigadier General Lauris R. Norstad, Colonel William P. Fisher, Colonel Paul W. Tibbets, Dr. David M. Dennison, and Dr. Robert Stearns. Manhattan Project representatives included Dr. John von Neumann, Dr. R. Bright Wilson, Dr. William Penny, Dr. Norman F. Ramsey, Colonel Lyle E. Seeman, and Major Jack Derry (who wrote the summary notes after each meeting).
 Jack Derry, “Notes on Initial Meeting of the Target Committee,” April 27, 1945, Groves “Top Secret,” file 5D.
 Derry, “Summary of Target Committee Meetings on 10 and 11 May 1945,” Groves, “Top Secret,” file 5D.
 One of the important criteria used by the committee in selecting a target was that it “be capable of being damaged effectively by a blast.” Ibid.
 Derry, “Notes on Initial Meeting of the Target Committee.”
 Derry, “Minutes of Third Target Committee Meeting -- Washington, 28 May 1945,” Groves, “Top Secret,” file 5D.
 Stimson to Truman, May 16, 1945, Stimson Diary.
 Diary of John J. McCloy, May 21, 1945, John J. McCloy Papers, box DY1, folder 17, Amherst College Library, Amherst, Mass. (hereafter cited as McCloy Diary).
 “Objectives,” [outline for draft of presidential address, author unknown but likely either Harvey Bundy or Arthur Page] May 25, 1945, Harrison Bundy Files Relating to the Development of the Atomic Bomb, 1942-46, Records of the Office of the Chief of Engineers, record group 77, microfilm publication M1108, file 74, National Archives (hereafter cited as Harrison-Bundy).
 McCloy, “Memorandum of Conversation with General Marshall.”
 On June 1, three days after this meeting with Marshall, Stimson summoned Arnold to question the general about "a bombing of Tokyo" that Stimson found objectionable insofar as it had apparently been aimed primarily at civilians and as such represented a breach “of my promise from Lovett that there would be only precision bombing in Japan.” Stimson Diary, June 1, 1945.
 McCloy, “Memorandum of Conversation with General Marshall.”
 Groves Diary, May 30, 1945, Papers of Leslie R. Groves, box 3, record group 200, National Archives II, College Park, Md. (hereafter cited as Groves Diary).
 Leslie Groves, Now It Can Be Told: The Story of the Manhattan Project (New York, 1962), 273; Stimson Diary, May 30, 1945. Also see the account in Robert S. Norris, Racing for the Bomb: General Leslie R. Groves, the Manhattan Project’s Indispensable Man (South Royalton, Vt., 2002), 386-87.
 Groves quoted in Len Giovannitti and Fred Freed, The Decision to Drop the Bomb (New York, 1965), 40-41.
 Stimson Diary, May 30, 1945.
 Groves, Now It Can Be Told, 275.
 Stimson Diary, June 1, 1945; Ira C. Eaker, "Memorandum for the Secretary of War," June 11, 1945, “Safe File,” box 8.
 Groves, “Memorandum to General Norstad,” May 30, 1945 (emphasis in original), Groves “Top Secret,” file 5D (emphasis added).
 The Diary of Henry H. Arnold, May 31, 1945, Henry H. Arnold Papers, Manuscripts and Records Division, Library of Congress (hereafter Arnold Diary).
 Gordon Arneson, “Notes of the Interim Committee Meeting,” May 31, 1945 (“this project,” “must be controlled”), Harrison-Bundy, file 100; Stimson Diary, May 31, 1945 (“Frankenstein”).
 For more on the debate over international control and the Soviet Union see Malloy, Atomic Tragedy, 80-95, 109-14, 131-34, 143-57.
 Ernest O. Lawrence to Dr. Karl K. Darrow, 17 August 1945, E. O. Lawrence Papers, box 28, folder 20, Bancroft Library, University of California, Berkeley.
 Arneson, “Notes of the Interim Committee Meeting,” May 31, 1945.
 Derry, “Minutes of Third Target Committee Meeting.”
 Michael Sherry has reached a similar conclusion regarding Stimson and the bomb. Michael S. Sherry, The Rise of American Air Power: The Creation of Armageddon (New Haven, 1987), 295.
 Stimson, “The Decision to Use the Atomic Bomb,” 105.
 The “shock” factor, while not entirely absent in wartime discussions became much more prominent and well defined after the war in post-facto justifications of the bomb’s use. For more on shock see, Alperovitz, The Decision to Use the Atomic Bomb, 165-66; Michael Gordin, Five Days in August: How World War II Became a Nuclear War (Princeton, 2007), 39.
 Richard Polenberg, ed., In the Matter of J. Robert Oppenheimer (Ithaca, 2002), 34.
 Derry, “Summary of Target Committee Meetings.”
 Derry, “Minutes of Third Target Committee Meeting.”
 For more see Malloy, Atomic Tragedy, 134-35, 166-69.
 Stimson Diary, June 6, 1945.
 “Transcript of Conference Held at 11 am, 9 May, 1945 with Stimson, Marshall and a Special Committee of the Senate and House of Representative Which Investigated ‘ATROCITIES’ in Germany,” “Safe File,” box 2.
 Stimson Diary, June 6, 1945.
 For a version of this argument see Stimson, “The Decision to Use the Atomic Bomb,” 107.
 Stimson, “Memorandum for the President: Proposed Program for Japan,” July 2, 1945, Stimson Diary.
 Stimson, “Memorandum for the President: The Conduct of the War with Japan,” enclosed in Stimson to James Byrnes, July 16, 1945, Stimson Papers, reel 113.
 Arnold Diary, July 22, 23, 1945; Henry H. Arnold, Global Mission (New York, 1949), 589.