Harry Truman, the Dropping of the Atomic Bombs on Japan, and the End of the Second World War

Abstract

On October 9, 1941, Franklin D. Roosevelt instructed Vannevar Bush, head of the Office of Scientific Research and Development, to find out whether an atomic bomb could be built and at what cost. Three months later Roosevelt approved the production of such bombs. The initial step of the endeavor, managed by Brigadier General Leslie Groves, was to find a way to harness the power of the atom to design and build a weapon that, if necessary, could be used to accelerate the ending of the war and, eventually, to shape “post war policies.”1 By early April 1945, the scientists had nearly achieved the assigned goal. 2 Sensing that victory in Europe was imminent, Roosevelt saw no need to use the new weapon against Germany to force its unconditional surrender. The war in the Far East, however, posed a different challenge. Because the fighting against Japan had been growing more violent and more deadly, Roosevelt was prepared to use the atomic bomb. He acknowledged that, after “mature consideration,” he might have no choice but to use it “against the Japanese” repeatedly “until they surrender.”3