In his authoritative new book Cultures of War: Pearl Harbor, Hiroshima, 9-11, Iraq (Norton, 2010) John Dower addresses the question — as hot as ever — of what drove Japan to surrender. Many today suspect that it wasn’t the atomic bomb, but the threat of a Russian invasion. Ultimately, using documents from the time, Dower one-ups even that one-time heresy. First, let’s examine what he writes about the threat of a Russian invasion.
Would the Soviet declaration of war alone have been decisive? . . . In a careful analysis of Japanese records between August 6 and August 17, the historian Tsuyoshi Hasegawa found only two statements (out of twelve) referring to the impact of the bombs [on Hiroshima and Nagasaki] alone; the rest emphasized both the bombs and Soviet action, or Soviet action alone. In Hasegawa’s own estimation, the Soviet entry rather than atomic bombs was the determining factor in forcing Japan’s hand.
Beyond that
. . . a few years after the war . . . the British physicist and 1948 Nobel laureate P.M.S. Blackett, who was involved in wartime military deployments [wrote]
So we may conclude that the dropping of the atomic bombs was no so much the last military act of the second World War, as the first major operation of the cold diplomatic war with Russia now in progress.
Also
The plain-speaking Vannevar Bush, who served as director of the Office of Scientific Research and Development from mid-1941 through the end of the war . . . when he was later asked what significance he attached “to the delivery of the A-bomb on time” [said]:
It saved hundreds of thousands of casualties on the beaches of Japan. It was also delivered on time so that there was no necessity for any concessions to Russia at the end of the war.
And the inimitable General Leslie Groves, who directed the Manhattan Project
casually observed, “You realize of course that the main purpose of this project is to subdue the Russians.”
In other words [emphasis added]
[American] decision makers opted [to use] the bomb essentially without warning in a manner that would shock and awe the Russians every bit as much as the Japanese — and, in the process, ideally deter them from their territorial ambitions in eastern Europe while simultaneously undercutting them in Asia. [This] reflected belated recognition of the strategic downside of Soviet entry into the war — a sudden fear . . . that even moderately prolonged Russian engagement with Japanese forces would strengthen the postwar Soviet position in Manchuria, the rest of China, and northeast Asia generally, including Korea, while simultaneously enhancing Moscow’s ability to demand a . . . territorial “zone,” as in occupied Germany . . . in the occupation of Japan.
In short, it wasn’t only the threat of a Russian invasion that drove Japan to surrender, that same threat — beyond even defeating the Japanese or, in general, putting the fear of God (or Stalin) into Russians about U.S. capabilities in a post-war world — may well have been what prompted the United States to use atomic bombs as expeditiously as it did. The United States didn’t want Russia to get a foothold in the Far East.
One could say, however barbaric, that was clever on the part of the United States. But, the last laugh is on us. As I wrote recently at Focal Points, the use of the bomb laid the foundation for the fear that has infected generations of Americans since — not just of the then Soviet Union, but of a much greater threat: nuclear weapons themselves.