Why Japan Surrendered

Why Japan Surrendered Robert A. Pape T h e end of World War I1 in the Pacific is the most successful case of military coercion among modern nation-states. On August 15, 1945, Japan unconditionally surrendered to the United States, although it still possessed a two-million-man army in the home islands which was prepared and willing to meet any American invasion, as well as other forces overseas. Indeed, Japan’s surrender represents a rare instance of a great power surrendering its entire national territory to an opponent that had not captured any significant portion of it. This coercive success saved the lives of tens of thousands of Allied soldiers and many more Japanese.’ From the standpoint of understanding coercion, what matters is not the exact date of Japan’s surrender, but the fact that it surrendered without offering last-ditch resistance. The key question is: why did Japan capitulate before invasion and decisive defeat of her home army? Debate has raged for decades over this question. This prolific literature offers three principal explanations, all of which assume that civilian vulnerability was the key to coercion. The first argues that the decisive factor was fear of future punishment from atomic bombing: ”It was not one atomic bomb, or two, which brought surrender. It was the experience of what an atomic bomb will actually do to a community, plus the dread of many more, Robert P a p is an assistai7t professor 111 the Schoul of Advanced Airpower Studies, Air University, Maxwell Air Force Base, Alabama. I thank Robert Art, Mark Clodfelter, Michael Desch, Matthew Evangelista, Paul Huth, Akira Iriye, John Mearsheimer, David Mets, and Stephen Walt for helpful comments. I also wish to acknowledge an extraordinary debt of gratitude to Chaim Kaufmann for all the help he gave with this article. 1. Contrary to exaggerated claims at the time that Japan’s surrender saved a half million American lives, Rufus Miles persuasively estimates that the invasion of Kyushu, the southern most of Japan’s four main islands, would have cost perhaps 20,000 American deaths. While estimates for Japanese casualties are unavailable, they would likely have resembled those during Pacific operations from March 1944 through May 1945, in which Japanese losses were over twenty times higher than American casualties. Rufus E. Miles, Jr., ”Hiroshima: The Strange Myth of Half a Million American Lives Saved,” International Security, Vol. 10, No. 2 (Fall 1985), pp. 121-140. International Securify, Vol. 18, No. 2 (Fall 1YY3), pp. 154-201 0 1993 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology. 154 Why Japan Surrendered I 155 that was effective.”2 Japan surrendered, it is argued, to avoid the risk of having its population centers annihilated. The second focuses on the effects of conventional strategic bombing on Japan’s population. This position is largely identified with the United States Strategic Bombing Survey (USSBS):”It was not necessary for us to burn every city, to destroy every factory, to shoot down every airplane or sink every ship, and starve the people. It was enough to demonstrate that we were capable of doing all this.”3 The decline in morale had a profound effect on Japan’s political leadership, according to the USSBS: ”At the time surrender was announced, [low morale] was rapidly becoming of greater importance as a pressure on the political and military decisions of the rulers of the country.”4 The third explanation stresses American demands, contending that Japan’s decision resulted from a concession by the United States, permitting Japan to retain the emperor. This concession reduced the costs of surrender, and so made Japan willing to give in rather than face the continued suffering of its ~ociety.~ The principal implication of all three of these arguments is that had American air power not driven up the costs and risks to civilians, Japan would not have surrendered prior to invasion of the home islands. However, none of these explanations is consistent with the facts. First, the argument that the threat of atomic attack coerced Japan fails, because conventional bombing had already achieved such a high level of destruction that atomic bombs could not inflict dramatically more...