Few historical counterfactuals are as sobering as the prospect of a full-scale U.S. invasion of the Japanese home islands in 1945. By the summer of that year, Japan’s strategic position was untenable. The Imperial Navy had been shattered, American bombers roamed its skies with impunity, and a naval blockade was strangling its economy. Yet, the war’s inevitable outcome should not be mistaken for an inevitable collapse. Had the Allies executed Operation Downfall—the two-stage invasion of Kyushu and Honshu—the result would have been a bloodbath unprecedented even by the standards of the Pacific War.
