It comes up every year at the time of the anniversary. It is one of the most difficult and complex questions in American history. Why did the leadership of the United States choose to drop the atomic bomb on Japan in August 1945, not once but twice?
This represents one of the most complex, divisive, and nuanced debates in the history of the twentieth century. U.S. President Harry S. Truman in August 1945 chose to drop two atomic bombs from B-29s on Hiroshima and Nagasaki, Japan, thereby forcing Japan to surrender and thereby ending World War II. A traditional conception of the decision, indeed the one most often voiced by actors in the decision, was that it was done to speed the end of the war and thereby preserve American lives that might be lost in future combat.
A revisionist interpretation, often identified with Gar Alperowitz, argues that the war was almost over and that the Japanese were on the verge of surrender anyway. The reason to drop the bomb, therefore, had little to do with the ending of World War II and was aimed more at impressing and influencing future relations with the Soviet Union. Another interpretation suggests that the use of the atomic bomb had more to do with American racism, and that the U.S. would have refrained from using such a horrific weapon on other Caucasians in Europe. Other scholars condemn the use of such a weapon targeting large populations, including non-combatants, as immoral and obscene. Subsequent historians have argued various permutations of these interpretations and the debate remains far from settled.
In the end historians have offered five fundamental considerations that played into the decision by Truman to use atomic bombs in August 1945. First, the decision makers, especially Truman, sought to end the war at the earliest possible moment. They believed this new and terrifying weapon would do so and should therefore be employed for what they considered the greater good of ending the bloodshed. Wrapped up in this argument, although historian J. Samuel Walker, who has written a book on the interpretations of the decision, thinks it a bit of side issue, was a widely held belief that bringing the Japanese to the surrender table would require an invasion of its islands.
This would be, as those considering it believed, a costly and lengthy campaign that might mean the loss of thousands of lives on both sides. Casualty estimates of all types exist, and they have been used in the debate since then to justify or condemn the use of the bomb. Those estimates, which are at best educated guesses that range broadly depending on the assumptions and the perspectives of those making them, are less useful in assessing what took place than the understanding that Truman was unwilling to accept any more casualties than absolutely necessary.
Second, Truman and his advisors were intensely concerned that they had to justify the enormous cost of developing the atomic weapon, and a decision not to use it once it existed would open them to significant criticism. As historian J. Samuel Walker concluded in “prompt & utter destruction”: Truman and the Use of the Atomic Bomb against Japan (1997): “The success of the Manhattan Project in building the bombs and ending the war was a source of satisfaction and relief.”
In this context, Truman expressed great concern that should he decide not to use the weapon once he had it that every American life lost thereafter would have been wasted. As he explained to Secretary of State James F. Byrnes in 1947, “I believe that no man, in our position and subject to our responsibilities, holding in his hands a weapon of such possibilities for accomplishing this purpose and saving those lives, could have failed to use it and afterwards looked his countrymen in the face.”
Third, at least one of Truman’s advisors, Secretary of State Byrnes, realized immediately and argued to his colleagues that this weapon would be useful in helping to bend the Soviet Union to American wishes in the post-war era. Truman recognized this as well, but according to Walker this was definitely an added bonus and not the primary consideration in using the bomb. As Walker concluded, “Growing differences with the Soviet Union were a factor in the thinking of American officials about the bomb but were not the main reason that they rushed to drop it on Japan.” Gar Alperowitz’s “atomic diplomacy” thesis, therefore, has merit however overstated it might have been.
Fourth, there was a lack of incentives among those making these decisions not to use the bomb. “Truman,” as Walker notes, “used the bomb because he had no compelling reason to avoid it.” While many people since 1945 have questioned the morality of its use, Truman and his advisors did not let those scruples—and they did exist among them—outweigh their goal of ending the war as quickly as possible.
Indeed, by the last year of the war conventional weaponry had laid waste to so many cities containing thousands of non-combatants—witness the firebombing of Dresden and Tokyo—that virtually no one in a senior decision-making role in the U.S. questioned the use of nuclear weapons despite their destructiveness since they believed dropping these bombs would shorten the war and save American and perhaps enemy lives.
Fifth, there is no question that such comments as these affected the debate: “Hatred of the Japanese, a desire for revenge for Pearl Harbor, and racist attitudes were a part of the mix of motives that led to the atomic attacks.” Again, this was not the primary consideration in dropping the bomb on Japan, “But the prevalent loathing of Japan, both among policymakers and the American people,” according to Walker, “helped override any hesitation or ambivalence that Truman and his advisors might have felt about use of atomic bombs.”
There are a series of questions still being debated about the decision to use the bomb. These include: “(1) how long the war would have continued if the bomb had not been used; (2) how many casualties American forces would have suffered if the bomb had not been dropped; (3) whether an invasion would have been necessary without the use of the bomb; (4) the number of American lives and casualties an invasion would have exacted had it proven necessary; (5) whether Japan would have responded favorably to an American offer to allow the emperor to remain on the throne before Hiroshima, or whether such an offer would have prolonged the war; and (6) whether any of the alternatives to the use of the bomb would have ended the war as quickly on a basis satisfactory to the United States.
These historiographical questions ensure that future study of this subject will remain contested; overlaying all of it, of course, is the question of the morality of Truman’s decision. There is probably no conclusion to the debate, instead further inquiry and exposition will make a contribution to the marketplace of ideas where positions will be evaluated and accepted, rejected, or modified.