Warfare changed forever in the summer of 1945, when the United States detonated the world’s first atomic bombs. One was tested in the New Mexico desert, and the other two devastated the Japanese cities of Hiroshima and Nagasaki. Entire cities and their populations could now be wiped out with one strike. But until Japan’s final surrender offer, five days after the Nagasaki bombing, the atomic bomb’s reputation as a “war ender” would not take hold. During that time, the question of how the next atomic bomb would be used was a real one.
One of the most persistent claims about the end of World War II is that the United States had no more atomic bombs after the second attack and that President Harry Truman was bluffing when he promised to drop more on Japan if it did not unconditionally surrender. But this is a myth: It was no bluff.
In the closing months of World War II, the United States was producing as many atomic bombs as it could. Days away from having another bomb for a third attack, the United States was close to preparing it for deployment before the Japanese surrendered. Just hours before hearing of Japan’s final surrender on August 14, 1945, Truman had ruefully told a British diplomat that he had “no alternative” but to order a third atomic bomb attack. Had World War II lasted a few more days, the odds of a third bomb—and several more—were very high.