Extended Deterrence and Horizontal Nuclear Proliferation in South Korea

• In Event: Nuclear Politics in an Age of Mis- and Disinformation

Abstract

The nuclear extended deterrence provided by a patron state is expected to restrain the client state’s nuclear proliferation ambition if the commitment to the provision of extended deterrence is credible. We examine whether the credible U.S. extended deterrence can mitigate the public support for nuclear proliferation in its client state by focusing on South Korea where the public support for nuclear proliferation is politically salient and remains high. The results from our novel survey experiment conducted on a sample of 1,209 South Koreans show that an increase in the credibility of the U.S. extended decreases the public support for nuclearization but only to a very small extent, while a decrease in credibility does not influence the already high level of public support for nuclear proliferation. We propose the upward-constrained substitution hypothesis to explain this non-linear relationship between the credibility of extended deterrence and nuclear proliferation.

Authors

• Hye-Sung Kim, Appalachian State University

• Jeheung Ryu, Ewha Womans University

• Taehee Whang, Yonsei University