The ceremonies marking the 40th anniversary of Hiroshima's obliteration are over, and the ghostly figures of vaporized corpses that were stenciled on the sidewalks of scores of American cities have already begun to fade. What remains is a question, the same one that has gnawed at us from the first: Did the U.S. really have to drop the atomic bomb?
Harry Truman, the man who gave the order, explained often and emphatically that he did so for the simplest yet most compelling of reasons: to end the war. Such surety seems comforting. Yet one thing last week's observances showed is that such a simple explanation remains unsettling. We continue to poke through the rubble of history, compelled to search for clues about why something so incomprehensible can seem so explainable.
There were without doubt persuasive military reasons for using the new weapon in the summer of 1945. The first day of fighting on Iwo Jima had cost more American casualties than D-day; on Okinawa, 79,000 U.S. soldiers were killed or wounded. As the U.S. readied plans to invade the main islands, Japan was deploying up to 2 million soldiers and additional millions of "auxiliaries" who were clearly prepared to defend their homeland to the death. It was easy to believe estimates that an invasion would result in as many as a million American casualties, plus many more Japanese. The Bomb offered the chance of ending the war and saving lives.
In addition, the Bomb, like any new weapon, had developed a constituency and a momentum of its own. J. Robert Oppenheimer, the charismatic master of Los Alamos, gave short shrift to those scientists working under him who urged that their creation not be used. Congressional committees, the first of them led by a Missouri Senator named Truman, had long been grumbling about the huge secret appropriations poured into the Manhattan Project and warning that the results had better be worth the $2 billion investment, which was serious money in those days. When the scientists succeeded, it became all but impossible to argue that their weapon, one that could prevent a bloody invasion, should be shelved.
There was, however, another factor, one still enmeshed in historical controversy. By the end of July, Japan was reeling. It was likely that a Soviet declaration of war would be the coup de grace. Gar Alperovitz, a historical revisionist whose newly updated Atomic Diplomacy is a harsh critique of American policy, argues that Truman was well aware of this. One of his principal goals during the Big Three meeting in the Berlin suburb of Potsdam in July 1945 was to secure Stalin's pledge to enter the war within a few weeks. When the Soviet dictator agreed, Truman jotted in his diary: "Fini Japs when that comes about."