For 60 years the United States has agonized over its unleashing of the world's first nuclear weapon on Hiroshima on August 6, 1945. President Harry Truman's decision to explode an atomic bomb over an ostensible military target -- the headquarters of the crack Japanese 2nd Army -- led to well over 100,000 fatalities, the vast majority of them civilians.
Critics immediately argued that we should have first targeted the bomb on an uninhabited area as a warning for the Japanese militarists to capitulate. Did a democratic America really wish to live with the burden of being the only state that had used nuclear weapons against another?
Later generals Hap Arnold, Dwight Eisenhower, Curtis LeMay, Douglas Macarthur, and Admirals William Leahy and William Halsey all reportedly felt the bomb was unnecessary, being either militarily redundant or unnecessarily punitive to an essentially defeated populace.
Yet such opponents of the decision shied away from providing a rough estimate of how many more would have died in the aggregate -- Americans, British, Australians, Asians, Japanese, and Russians -- through conventional bombing, continuous fighting in the Pacific, amphibious invasion of the mainland, or the ongoing onslaught of the Red Army had the conflict not come to an abrupt halt nine days later and only after a second nuclear drop on Nagasaki.
Truman's supporters countered that, in fact, a blockade and negotiations had not forced the Japanese generals to surrender unconditionally. In their view, a million American casualties and countless Japanese dead were adverted by not storming the Japanese mainland over the next year in the planned two-pronged assault on the mainland, dubbed Operation Coronet and Olympic.