Abstract/Summary

This thesis seeks to offer a novel theoretical and empirical insight into the unique form of the United States (US) extended nuclear deterrence (END) - also known as a nuclear umbrella - provided to Japan. In contrast to the main trend of nuclear weapons deployment in America‘s close allies during the Cold War, Japan was only the key allied state that never hosted US nuclear weapons on its soil throughout the Cold War. Japan, instead, relied on US END backed by strategic forces mainly at sea. US END over Japan was thus "invisible" in that US nuclear weapons were not forward-deployed. This situation has not changed since it was developed in the 1960s. The thesis is an essentially historical project but its main aim is to understand US END over Japan today. Its approach is to use history as a tool to understand the present. The thesis unravels the complex developments of such deterrence between 1945 and 1970. More specifically it seeks to understand under what circumstances Japan came under the US nuclear umbrella and what factors have shaped "Invisible" END. The primary argument of this thesis is that public anti-military and nuclear sentiment in Japan shaped by its historical experience in the devastating World War Two significantly influenced the strategic calculations of Japanese leaders as well as American leaders. Key events in the foregoing period set social and political conditions on strategy making of Japan even today. The thesis will specifically examine the formation process of Japan‘s non-nuclear path chosen. In order to understand the non-nuclear path taken, the thesis will also examine the meaning of the Japan‘s alternative nuclear path. In fact there were some Japanese leaders such as Prime Minister Eisaku Sato, who clearly saw strategic value in nuclear deterrence. "Invisible" END was arguably a product of political compromise for Japan.