Non-Nuclear Threats to Nuclear Deterrence and Stability: The Case of South Korea

Abstract

The United States’ most vulnerable allies in East Asia are beginning to rethink their security strategies. Historically, “nuclear umbrella” states in East Asia, or major non-nuclear U.S. allies who are threatened by the nuclear forces of regional adversaries, have relied primarily on U.S. extended deterrence to counter security threats. More recently, however, South Korea, Taiwan and Japan have begun to take advantage of new advances in manufacturing and satellite-based modeling technologies in order to independently develop, or consider developing, advanced military capabilities, which were previously only available to nuclear-armed states. In light of these developments, this research explores the implications of new and emerging technologies on nuclear deterrence and stability. It does so by examining why non-nuclear allies, who are guaranteed protection by the nuclear forces of a major-power ally, are seeking enhanced conventional capabilities. Using the Republic of Korea (ROK) as a case study, this project explores the question: why is South Korea, despite being protected by the U.S. nuclear umbrella, acquiring independent strategic military capabilities? I argue that South Korea’s decision to acquire independent strategic weapons is driven by its perception of the inadequacy of current forms of extended deterrence to ensure its security and that it allows South Korea to affect outcomes regarding strategic stability in the Korean peninsula. By extension, this research also argues that new and emerging technologies are offering non-nuclear allies like South Korea the means through which to reshape the asymmetrical relationship between the patron state providing extended deterrence and the client state, with implications for regional and international security dynamics.