Documents on the order to drop the atomic bomb on Hiroshima
From International Security, Fall 1985, vol. 110, no.2, pages 121-140
Hiroshima -- The Strange Myth of Half a Million American Lives Saved
By Rufus E. Miles, Jr.
Rufus E Miles Jr. is a former senior fellow of the Woodrow Wilson School, Princeton University, and a former thirty-year career official of the U.S. government.
OF all the political and military decisions in history, few have been subject to more analysis and comment than the atomic bombings of Hiroshima and Nagasaki. It is mystifying, therefore, that historians have not long ago exploded the demonstrable myth that those attacks probably saved half a million lives of American soldiers, sailors, and marines, and prevented numerous British fatalities and vast numbers of Japanese deaths, as President Truman alleged in his autobiography a decade after the war's end.
Such a justification was neither needed nor used by President Truman in the weeks immediately following the obliteration of Hiroshima, followed within days by the surrender of Japan, since the public overwhelmingly approved of the action. As time went by, however, and questions were increasingly asked about the necessity and wisdom of launching the age of nuclear weapons in this manner, estimates of deaths averted were adduced as an important element -- perhaps the most important element -- of the moral justification for Truman's decision.
By the time historians were given access to the secret files necessary to examine this subject with care, the myth of huge numbers of American, British, and Japanese lives saved had already achieved the status of accepted history. Even when secret wartime documents were declassified, historians did not focus on the striking inconsistencies between these documents and those parts of the principal decision-makers' memoirs that dealt with estimates of lives saved. Had they done so, and followed the subject where it led, they would have been forced to conclude that the number of American deaths prevented by the two bombs would almost certainly not have exceeded 20,000 and would probably have been much lower, perhaps even zero.
Four days after 70,000 -- 80,000 citizens of Hiroshima died from the atomic bomb blast on August 6, 1945 and many thousands more were injured, and one day after half as many residents of Nagasaki met a similar fate, the Japanese communicated to the United States their urgent desire to surrender, subject only to the condition that they might keep their Emperor. On the next day, the United States accepted that condition with the stipulation that, until total demilitarization had been achieved and other Allied demands had been met, "the authority of the Emperor and the Japanese Government to rule the state shall be subject to the Supreme Commander of the Allied Powers." Three days later, on August 14, Japan accepted the stipulation, and the war was over. Understandably, the American people were euphoric that the most devastating war in history had ended. Not surprisingly, they gave principal credit to the new weapon.
A Fortune magazine poll taken two months after Japan's capitulation showed that less than 5 percent of Americans, as a matter of principle, disapproved of the military use of a bomb a thousand times as powerful as any of its predecessors. Some 22 percent, still seething over the infamous "sneak" attack on Pearl Harbor, wished that more such bombs had been quickly dropped before the Japanese had a chance to surrender. Nevertheless, an articulate minority, deeply concerned over the possibility of a world armed with atomic weapons, began to raise questions about the decision to drop the bombs. At the same time, some of Truman's advisers, most notably Secretary of War Henry L. Stimson, the overseer of the Manhattan Project that developed the fission bombs, felt the need for a fuller explanation and justification for the first use of these bombs than simply the quick end of the war. Had the bombs not been used, Stimson strongly implied in the February 1947 issue of Harper's, a massive and costly invasion of Japan would have been necessary. In his words:
We estimated that if we should be forced to carry this plan [to invade first Kyushu and then Japan's main island of Honshu] to its conclusion, the major fighting would not end until the latter part of 1946, at the earliest. I was informed that such operations might be expected to cost over a million casualties, to American forces alone. Additional large losses might be expected among our allies, and of course, if our campaign was successful and if we could judge by previous experience, enemy casualties would be much larger than our own.
Stimson's estimate of the consequences of what he implied was the only effective alternative to the use of the bomb thus became the main reference point for the rest of the 1940s and, as a result, has been influential ever since. Neither in the Harper's article nor in his autobiography, published later in 1947, did Stimson divulge any specific source of this forbidding estimate of casualties or when and how it had been calculated. It was simply implied that the casualty projections had been thoughtfully and carefully arrived at within the War Department.
Six years later, Winston Churchill described in his memoirs the mutual massacre that he imagined was avoided by the unforgettable flight of the "Enola Gay" over Hiroshima and the instantaneous destruction of the city:
I had in my mind the spectacle of Okinawa island, where many thousands of Japanese, rather than surrender, had drawn up in line and destroyed themselves by hand-grenades after their leaders had solemnly performed the rite of hara-kiri. To quell the Japanese resistance . . . might well require the loss of a million American lives and half that number of British. . . . Now all this nightmare picture had vanished. In its place was the vision -- fair and bright indeed it seemed -- of the end of the whole war in one or two violent shocks. . . . To avert a vast, indefinite butchery, to bring the war to an end, to give peace to the world, to lay healing hands upon its tortured peoples by a manifestation of overwhelming power at the cost of a few explosions, seemed, after all our toils and perils, a miracle of deliverance.
Both men thus presented the issue as if the sole practical alternative to the use of atomic bombs was an immense, long, and bloody invasion of the heartland of Japan, but neither provided any support for this belief. They apparently assumed that this premise would be accepted without question, and it was, even though it was severely flawed. Where the statements differ is that Churchill pictures a million American deaths, while Stimson had mentioned a million American casualties, implying, on the basis of Pacific experience, a fifth as many deaths. (Casualties include injured and temporarily missing.) This discrepancy led me to search for its origin and, in doing so, to find much more than the careless and imprecise use of terms and figures.
The purpose of the analysis that follows is to show that, if a decision had been taken not to use the atomic bomb, there were three non-nuclear strategies, each of which was considered in some degree by President Truman and his military and civilian advisers, and all three of which could have been tried, seriatim, with an extremely high probability of success and with a relatively small number of deaths. The first, in fact, might have achieved its purpose with no fatalities at all. A fourth alternative -- the massive invasion of Honshu if all else failed -- will be shown to have been clearly unrealistic; furthermore, there is a compelling case that, even if it had occurred, the number of American deaths would have been nowhere near half a million. The following analysis of the four courses of action seeks to understand why Truman, Churchill, and Stimson used grossly exaggerated figures in their memoirs. The use of the atomic bombs must have been based largely on other considerations than the saving of huge numbers of American lives. Yet the myth persists that this was the most important factor in the decision.
Strategy Number One: A Negotiated Peace
In the spring of 1945, evidence mounted that the capacity of the Japanese air force to defend its homeland against escalating bombardment had rapidly deteriorated. This information, accompanied by a sharp drop in losses of American planes and pilots, convinced Acting Secretary of State Joseph Grew that the Japanese would be open to a negotiated peace. Grew believed that the Japanese were so nearly beaten by the end of May 1945 that there was an excellent chance that they would capitulate soon thereafter if the unconditional surrender doctrine Truman had inherited from Roosevelt were publicly interpreted by Truman to allow retention of the Japanese Emperor -- the revered symbol of the thousand-year-old Japanese dynasty. Grew was the only official of Cabinet status or of high military rank with access to the President who had had lengthy experience in Japan (ten years as U.S. Ambassador there) and thus was able to assess the attitudes of Japan's ruling group. Grew sought to persuade Truman of his views on May 28, three weeks after V-E Day.
The timing was propitious in Grew's judgment since B-29s were causing enormous devastation throughout Japan. On March 29 they had rained incendiaries on Tokyo, killing and injuring more Japanese (83,000), it was later estimated, than did the Hiroshima bomb (70,000 -- 80,000). By the end of May, virtually all major Japanese cities had been attacked with incendiaries, disastrously impairing Japan's capacity to carry on the war. Truman, then President for only a month and a half, was impressed by Grew's arguments but thought it best to have him discuss his proposals with the Secretaries of War and the Navy and the Joint Chiefs of Staff. Grew did so on the following day, May 29.
By coincidence, on the same day on which Grew met with Truman, Harry Hopkins, Roosevelt's trusted international trouble-shooter, who had been called out of retirement by Truman to improve worsening relations with Stalin, was meeting in Moscow with the Soviet leader. Hopkins cabled Truman that "Japan is doomed and the Japanese know it. Peace feelers are being put out by certain elements in Japan and we should therefore consider together our joint attitude and act in concert about the surrender of Japan."
Grew's recommendation did not, however, come as a new idea to those present. The Joint Chiefs had been presented a month earlier with a report from their planning staff that contained the following statement: "The concept of 'unconditional surrender' is foreign to the Japanese nature. Therefore, unconditional surrender' should be defined in terms understandable to the Japanese who must be convinced that destruction or national suicide is not implied. This could be done at the governmental level by a 'declaration of intentions' which would tell the Japanese what their future holds. Once convinced of the inevitability of defeat, it is possible that a government could be formed that would sign and could enforce a surrender instrument."
Secretary of War Stimson and Secretary of the Navy James Forrestal seemed especially receptive to such a "declaration of intentions," but not eager to issue it immediately for reasons that were not clear to Grew. Stimson, almost totally preoccupied with the diplomatic and military implications of the atomic bomb, scheduled for test in early to mid-July, had been discussing the use of the bomb with Truman, including the probable need to make a crucial decision during the Potsdam meeting in late July. If the declaration of intentions were to be delayed until the bomb became a tested military weapon, the Japanese might be warned of its power while simultaneously being assured that "unconditional surrender" did not mean an end to the sovereignty of their nation or of their imperial dynasty. Because of the extreme secrecy of the "S-1 " -- the code for the atomic bomb -- Stimson could not reveal his reasons for counseling delay.
Within the Department of State, there was less agreement than there was in the War Department over the idea of redefining the unconditional surrender doctrine. Assistant Secretaries Dean Acheson and Archibald MacLeish argued against any change in the Roosevelt doctrine of total surrender, not only because they felt sure it would be very unpopular with the American public, but because they took a dim view of the Emperor and regarded him as having been a tool of the infamous Premier Tojo and his military clique, and even as a possible subject of war crimes prosecution. Both saw him as a stumbling block to the development of genuine democracy in Japan. Despite this opposition, Grew, with the support of his Far East expert, Eugene Dooman, persisted in his efforts. Yet he was to be disappointed. On the morning of June 18, Truman met with Grew and indicated that, while he was favorable to the idea of issuing a declaration of intentions to the Japanese to reassure them on the matter of their long-term sovereignty, he had decided to wait until the Potsdam conference a month later and issue it as a joint proclamation.
On the afternoon of the same day, President Truman held a meeting with the Joint Chiefs of Staff, Secretaries Stimson and Forrestal, and Assistant Secretary of War John McCloy to help prepare himself for the Potsdam conference. He wanted to be briefed on the invasion plan that the War Department had prepared for an assault on Kyushu, Japan's southern island, scheduled for November I . Toward the end of the discussion, Admiral William Leahy, the President's personal chief of staff, recommended modification of the unconditional surrender doctrine. The minutes of that meeting record the following exchange:
"Admiral Leahy said he could not agree with those who said to him that unless we obtain the unconditional surrender of the Japanese that we will have lost the war. He feared no menace from Japan in the foreseeable future, even if we were unsuccessful in forcing unconditional surrender. What he did fear was that our insistence on unconditional surrender would result only in making the Japanese desperate and thereby increasing our casualty lists. He did not think this was at all necessary.
By July -- the month of the Potsdam conference with Truman, Churchill, and Stalin -- the momentum of Japan's peace party developed very much as Grew had predicted. On July 12, Foreign Minister Togo, at the Emperor's behest, instructed the Japanese Ambassador in Moscow, Naotake Sato, to inform Foreign Commissar Molotov that the Emperor wanted the war ended immediately and wished to send Prince Fuminare Konoye to Moscow with power to negotiate a peace on almost any terms, presumably short of the unacceptable sacrifice of the imperial dynasty. Ambassador Sato was rebuffed in his efforts to gain the cooperation of the Soviet Union as an intermediary, in large part because the Soviets were not eager to have Japan surrender before the U.S.S.R. could carry out its agreement, made at Yalta, to enter the war against Japan and claim its share of the spoils. On the next day, July 13, three days before the successful atomic test at Alamogordo, New Mexico, naval intelligence monitors intercepted and decoded the cables between Foreign Minister Togo in Tokyo and Ambassador Sato in Moscow. They read, in part:
Togo to Sato: "See Molotov before his departure for Potsdam. Convey His Majesty's strong desire to secure a termination of the war. . . . Unconditional surrender is the only obstacle to peace. . . .
Lewis Strauss, then special assistant to Secretary of the Navy Forrestal, recalled later that Admiral Redman, Chief of Naval Communications, brought him these intercepted messages on July 13, and that subsequent intercepts grew more desperate. Strauss said that as fast as they were received Forrestal sent them to Admiral Leahy, who was then with Truman in Potsdam. Forrestal had not been invited to attend the Potsdam conference but finally decided to go anyway, carrying with him the file of decoded messages, the last of which was dated July 25. Mentioning the imminence of a complete collapse, it instructed Ambassador Sato to go to any place that Molotov might designate, and while still maintaining "unconditional surrender" to be unacceptable, to state that Japan had "no objection to a peace based on the Atlantic Charter."
Immediately on Forrestal's arrival in Potsdam on July 28, he took the messages to the new Secretary of State, James F. Byrnes, who saw them "in detail" for the first time, although he had previously known of their existence and presumably the thrust of their content. In Strauss's words, "Forrestal was too late by forty-eight hours. The Potsdam Declaration -- the ultimatum to Japan -- had been dispatched on the twenty-sixth, and events were now in the saddle, riding the decision-makers." On the very day Forrestal and Byrnes were talking, Japan characterized the ultimatum with a unique Japanese word, mokusatsu, meaning "not worth of reply. " Although the ultimatum reassured the Japanese that they would remain a sovereign nation, it failed to assure them that they might keep their Emperor, and it promised stern justice to all war criminals. No mention was made of the atomic bomb.
Five days later, there was one last intercept. "The battle situation has become acute," it said, and concluded, "Since the loss of one day relative to this present matter may result in a thousand years of regret, it is requested that you immediately have a talk with Molotov. "
After the successful test of the atomic bomb on July 16, President Truman and his advisers felt sure that they had the means to end the war quickly without any concessions to or negotiations with Japan. And the Soviets had every reason to want to carry out their pledge to enter the war on or about August 8, thus staking out a share of the credit for the Pacific victory and the division of power in its aftermath. Upon Japan's rejection of the Allied ultimatum, the dynamics of the situation seemed to the decision-makers clearly to favor the prompt use of the new weapon.
As soon as Japan rejected the Allied demand on July 28, the Air Force had its green light. The Hiroshima bomb was dropped on August 6. The Soviet Union, as promised, declared war on Japan on August 8. The Nagasaki bomb was released on August 9. Japan sued for surrender on August 10, on the condition that they could keep their Emperor. The United States accepted Japan's conditional surrender on August 11, with certain stipulations. Three days later, Japan agreed to the stipulations. The war was over.
The Grew strategy, which had envisioned a successful American diplomatic effort to end the war by an offer and acceptance of a "conditional surrender" (the same condition that became the accepted basis for surrender in August) by the end of July, was subsequently considered by several people to have had more than an outside possibility of success. Among those who thought so in retrospect, in addition to Grew himself, were Hanson Baldwin, military analyst for The New York Times, and Robert J.C. Butow, author of Japan's Decision to Surrender. Especially significant was the view expressed by Secretary of War Stimson, as stated in his autobiography, co-authored with McGeorge Bundy. "It is possible," said Bundy, "in the light of the final surrender, that a clearer and earlier exposition of American willingness to retain the Emperor would have produced an earlier ending to the war. . . . But in the view of Stimson and his military advisers, it was always necessary to bear in mind that at least some of Japan's leaders would seize on any conciliatory offer as an indication of weakness." At another point Bundy writes: "Only on the question of the Emperor did Stimson take, in 1945, a conciliatory view; only on this question did he later believe that history might find that the United States, by its delay in stating its position, had prolonged the war."
Obviously, if the Grew -- Stimson approach had been tried and proved successful, the use of the atomic bombs would have been unnecessary and could have saved no lives. It might have brought the war to the same conclusion, possibly even before the atomic bombs were dropped and before the Soviet Union had time to enter the war against Japan.
Strategy Number Two: Intensified Bombing and Blockade Until November 1, 1945
This scenario is based on the assumption that the war might have continued with the use of conventional weapons during the period from early August until the Japanese surrendered, and that capitulation would have occurred prior to November 1, 1945 -- the date of the scheduled invasion of Kyushu. During this period, the United States would have tightened its sea blockade and intensified its air bombardment. This hypothesis brings into bold relief the deteriorating condition of Japanese defenses and the accumulation of evidence that Japan would have surrendered before the scheduled date for the invasion of Kyushu, even without the atomic bomb. The following excerpts from postwar official reports make this clear:
Admiral Ernest King, Commander-in-Chief, United States Fleet:
The devastation of Japan prior to the bombing of Hiroshima was confirmed by the Strategic Bombing Survey established by Stimson to assess the effects of the massive air attacks. The 1,000 members of the Survey interviewed hundreds of Japanese military officers, government officials, political and economic leaders, and others, and reviewed great numbers of Japanese records. At the end of this lengthy process, the conclusion of the Survey was:
Based on a detailed investigation of all the facts and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to I November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated.
These and other reports were available to Stimson, Churchill, Truman, and others when they wrote their memoirs. Yet they showed no evidence of having paid any attention to those records. The mass of data presented by the Survey and its conclusions are simply not compatible with the clear implication of these men that without the use of the atomic bombs as many as a million American casualties or, alternatively, a half-million deaths might have had to be paid in battles in the heartland of Japan. It seems probable that what these memoirists meant to convey was that, at the time of the decision, they thought that this number of losses could be avoided by the use of atomic weapons, although later information made them realize that Japan was closer to surrender than earlier U.S. intelligence assessments had led them to believe. But that is not what they said. They had a responsibility to make this distinction clear. Even had they done so, however, many unanswered questions and inconsistencies would have remained.
According to this second scenario, based on information available after the war's end, American casualties would have been, at most, in the low thousands, with the number of deaths almost certainly not exceeding 5,000 and probably considerably less. So great was the destruction of Japanese air power that American aircraft losses from bombing missions over Japan dropped from a high of 5.7 percent in January to 0.4 percent in July. Naval losses would also have been extremely light, judging from the reports of Admiral King. Since Army ground forces would not have been engaged at all, losses would have been either zero or negligible.
In the light of General Marshall's and Admiral King's assessments of the extremely weak condition of Japan during the last months of the war, and in view of the conclusions of the Strategic Bombing Survey that Japan would in all probability have surrendered before November 1, 1945, and considering the shock to Japan of the Soviet declaration of war on August 8, this second scenario seems, in retrospect, to have been the more probable one in the event the atomic bombs had not been available or had deliberately not been used.
It can only be a matter of conjecture as to how long it would have taken Japan to surrender after the Soviet Union's declaration of war, and as to how many casualties would have been inflicted on Japanese forces and civilians pending final peace terms, but the evidence strongly suggests that surrender would have come quickly. The shock and demoralization of Japanese military officers that resulted from the Soviet attack was similar in effect to the Hiroshima bomb, in the opinions of Lt. General Seizo Arizue, chief of G-2 of the Japanese Army General Staff, and Genki Abe, Home Minister in the Japanese Cabinet, according to their postwar statements. Especially since the Emperor was then taking an unprecedented role in seeking a prompt end to the war, it seems highly probable that, even by itself, the sudden Soviet assault would have shifted the Japanese government's intense surrender efforts from communicating with the Soviets to negotiating with the United States via Switzerland, as occurred after the double shock of the atomic bombings and the Soviet entry into the war.
Key U.S. officials not only wanted to save American lives, but, as Army historian Louis Morton observed, ". . . some responsible officials feared the political consequences of Soviet intervention and hoped that ultimately it would prove unnecessary. " Any tentative peace offer made to the United States through Switzerland, therefore, would have been immediately pursued and concluded, especially since the Secretaries of War and Navy, Stimson and Forrestal, and their Joint Staff Planners had come to the conclusion in April that a statement to Japan that they could retain their sovereignty -- and by implication their Emperor -- might in their dire circumstances, end their resistance.
Because relations between the United States and Japan have followed so cordial a path for four decades, there has been an effort, especially of late, to make it appear that if the two atomic bombings had not occurred, the Japanese people would have suffered massive slaughter or starvation, or both,. in an Allied invasion of Honshu, and that, from the Japanese standpoint, the bombings might properly be viewed as benign. This thesis was advanced two years ago by Dr. Taro Takemi, president of the Japanese Medical Association, and by Edwin O. Reischauer, former U.S. Ambassador to Japan. The evidence presented here, plus evidence from Butow's Japan's Decision to Surrender, makes their argument seem extremely questionable.
Strategy Number Three: A November 1945 Attack on Southern Kyushu
This scenario assumes that, despite a tight naval blockade and extremely heavy bombing for three months after early August, as well as critical losses against Soviet armies in Manchuria and possibly Korea, the Japanese still would have wanted to hold out and would have been able to do so, and that they would not have surrendered until after the invasion of Kyushu, scheduled to begin on November 1, 1945. This scenario further assumes that the invasion would have proceeded according to the War Department's plan and that within thirty days the United States would have won the battle for southern Kyushu. This represents the most pessimistic of the possibilities envisioned by the Strategic Bombing Survey.
The meeting at which Truman gave his approval to the invasion plan, if that became necessary, was an important one. It was convened on June 18, 1945, with the Joint Chiefs of Staff, the Secretaries of War and Navy, the Assistant Secretary of War, and Admiral Leahy, the President's personal chief of staff. This was the same meeting at which Admiral Leahy unsuccessfully advocated modifying the unconditional surrender doctrine to permit the retention of the Emperor. Following are the other salient points of the meeting.
Top naval and air corps officers believed that Japan could be forced to surrender through the strangulation of its military machine and its economy by naval blockade and air bombardment. That view was not presented at this meeting because these officers had been persuaded by their Army ground force counterparts to think of the conquest of southern Kyushu as the final military engagement in such a strangulation strategy, to be accomplished at a tolerable cost -- 31,000 casualties, 7,000 -- 8,000 deaths, the price paid for Luzon. The discussion would have been very different if the War Department had sought preliminary approval of the invasion of Honshu, which both the Navy and the Army Air Force regarded as sure to be more expensive in human losses than was necessary.
If this "worst-case scenario" had occurred -- that is, if the atomic bomb had not worked or had not been used, and if Japan had somehow held out beyond November 1, 1945, and if the successful invasion of southern Kyushu had been carried out, and if the Russians had entered the war in August (as they did) and engaged the Japanese in Manchuria and Korea, and if at that point the Japanese had surrendered -- then a reasonable estimate of American deaths almost surely would have been not more than 20,000 and probably less than 15,000 (5,000 for air and naval losses before the invasion, not more than 10,000 during the invasion of Kyushu, and an added allowance of 5,000 for unforeseen losses).
Strategy Number Four: A Spring 1946 Invasion of Honshu
The fourth strategy is the one we began with -- that which Stimson, Churchill, and Truman implied would have been the only alternative to the Hiroshima and Nagasaki bombings. It is based on the following assumptions:
In addition to these assumptions, this scenario asks that we believe that after the conquest of Kyushu, at a cost of under 15,000 deaths and probably no more than 7,000 -- 8,000, and after all of the above conditions had been realized, if President Truman had been presented with a plan for the invasion of Honshu that was estimated to cost half a million American deaths and many more Japanese troops, he would have approved it. It does not seem credible.
The puzzle is especially confounding when one seeks to determine where Stimson's figure of a million potential casualties -- the figure he first used in his 1947 Harper's article -- came from. There seems to be no evidence that any systematic and thoughtful effort was ever made by the War Department to estimate what it would cost in casualties or lives if Honshu were invaded. One is forced to conclude that Stimson's figure must have been an "off-the-top-of-the-head" estimate made in the early spring of 1945, before the War and Navy departments realized how rapid was the deterioration of Japan's capacity to resist, and then uncritically repeated on various occasions after the situation had radically changed.
One partial and plausible answer to the puzzle may be found in an obscure letter that Truman wrote on January 12, 1953, eight days before he left office. In reply to an inquiry by Professor James C. Cate, a former Air Force historian then at the University of Chicago, Truman said, "I asked General Marshall [at Potsdam] what it would cost in lives to land on the Tokyo plain and other places in Japan. It was his opinion that such an invasion would cost at a minimum a quarter of a million American casualties. and might cost as many as a million, with an equal number of the enemy. The other military men agreed." Here, Truman talks of casualties, as Marshall surely would have. But if we use the Pacific ratio of deaths to casualties, Marshall is estimating a minimum of 50,000 American deaths and a possibility of as many as 250,000, quite different from the figures used by Truman two years later in his autobiography. Marshall's estimate in this version, it should be noted, was in response to Truman's specific question as to what it might cost to conduct a massive invasion of Honshu, and makes no mention of any discussion as to whether circumstances had by then changed to make the need for such an invasion very remote and its advisability even more questionable. One of Marshall's biographers, Forrest Pogue, believes that by then Marshall felt sure that Japan would capitulate before such an invasion could occur. This was also the view of Brigadier General George A. Lincoln, one of the Army's top planners.
Perhaps the strangest part of this last scenario is that the participants in the decision-making process -- those who wrote their memoirs and used these estimates of lives that may have been saved by the use of the atomic bombs, especially Secretary Stimson in 1947 and President Truman in 1955 -- did not seem to realize either its extreme unlikelihood or the implication that they and General Marshall would have agreed to such an invasion of Honshu if they actually believed that a half-million American deaths might eventuate.
Strangulation of Japan without the invasion of Honshu would surely have been tried first. Even more likely, Truman would have acted upon the belief of Grew, Stimson, Forrestal, and the Joint Chiefs of Staff that the unconditional surrender doctrine could and should be tempered enough to negotiate a conditional surrender that would end the war without an extremely costly invasion -- the same conditional surrender that did end the war on August 14.
Why Truman used the figure of half a million American deaths prevented seems something of a mystery at first. He never approved a plan that would have involved such a mutual massacre and, beyond any reasonable doubt, he never would have. In psychological terms, however, such an estimate of potential American losses is not mysterious. The use of these figures by Truman and others can be explained by a subconscious compulsion to persuade themselves and the American public that, horrible as the atomic bombs were, their use was actually humane inasmuch as it saved a huge number of lives. The larger the estimate of deaths averted, the more self-evidently justified the action seemed. Exaggerating these figures avoided, in large part, the awkward alternative of having to rethink and explain a complex set of circumstances and considerations that influenced the decision to drop the bombs.
THIS analysis points strongly to the conclusion that the number of American lives saved as a result of the dropping of the two bombs was, with a high degree of probability, not more than 20,000 and was quite probably considerably less. This is not a judgment as to whether the decision to drop the bombs was a sound decision on other grounds. What it says is that the traditional rationale for the decision -- that half a million American lives might have been lost in an all-out invasion of Japan had the bombs not been used-simply does not hold up under careful examination, and that the action must be explained in some other way.
Truman and Stimson offered succinct and corroborating versions of the basic reason for the decision:
Truman: "Let there be no mistake about it. I regarded the bomb as a military weapon and never had any doubt that it should be used. The top military advisers to the President recommended its use, and when I talked to Churchill he unhesitatingly told me he favored the use of the atomic bomb if it might aid to end the war. "
In the minds of most of the top military and civilian officials of the government, the decision made by Roosevelt in 1942 to develop the atomic bomb carried with it the implicit intent to use it as soon as it became available if it would shorten the war. There was no need to take into account other considerations. The question was not whether the bomb should be used, but how. Its legitimacy to gain a quick end of the war was taken for granted. That this was the most powerful single influence in the decision to use the bomb seems highly probable. Like all the new and more lethal weapons in history, the atomic bomb was , its own imperative.
That there were other influential considerations, however, there can be no question. The most powerful of these concerned immediate relations with the Soviet Union. After the successful test of the first bomb on July 16, while Truman, Churchill, and Stalin were meeting in Potsdam, it became evident to the American delegation that this new weapon -- as an actuality, not a scientific forecast -- had suddenly metamorphosed the strategic situation. From the Cairo Conference in November and December 1943, President Roosevelt and General Marshall, and later President Truman, had been eager to have the Soviets help the United States defeat Japan. As Truman and Marshall left for Potsdam, it was still one of their major purposes to gain a renewed commitment from Stalin that the Soviets would shortly declare war against the Japanese empire. However, after the full report of the effects of the atomic blast at Alamogordo reached Potsdam on July 21, estimating that the energy generated was the equivalent of 15,000 to 20,000 tons of TNT or more, American officials realized that they had the means to end the war very quickly without help from the U.S.S.R. and before the Soviets could effectively stake a claim for the joint occupation of Japan, as they had done in Germany, and otherwise gain political and military advantages in East Asia that might go beyond the Yalta agreement. Harry Hopkins had reported on May 28 that Stalin expected to participate in the joint occupation and administration of Japan. A less appetizing prospect could hardly be imagined by Truman. In retrospect, it seems completely understandable that, if the bomb were to be employed at all, its most advantageous use would be as early as possible. Truman's concern is well illustrated by a brief instruction from him to General Marshall within hours after the United States had accepted Japan's conditional surrender on August 11. Truman ordered the War Department to move immediately to occupy a major Korean port and a major port on the Chinese coast, provided they could get there ahead of the Soviets.
The combination of the unquestioned legitimacy of the bomb as a military weapon and the double rationale for using it quickly -- its shock value to end the war abruptly and save whatever the number of lives, and its effectiveness in forestalling the Soviets from what might be large military gains and corresponding political demands in East Asia -- were almost surely strong influences on Truman when he made his decision in Potsdam. To fault him, in hindsight, for that decision would be to ignore the circumstances and atmosphere that surrounded the decision. The more appropriate question is:
Why were the circumstances and atmosphere not conducive to terminating the war without the onus being placed on the United States for the legitimization of nuclear weapons in the arsenals of the world?
For nearly four decades, the belief that the Hiroshima and Nagasaki bombs averted hundreds of thousands of American deaths -- far more than those bombs inflicted on the Japanese -- has been a part of accepted history. It was this judgment, more than any other factor, that seemed to give legitimacy to the American use of nuclear weapons. Discovering that this premise was false should help to stimulate a hard rethinking of other premises of U.S. nuclear weapons policies.
(c) 1985 by the President and Fellows of Harvard College and of the Massachusetts Institute of Technology.