Nuclear Posture and Nuclear Proliferation: Experimental Evidence from South Korea
While South Korea remains a non-nuclear U.S. ally under the protection of the U.S. nuclear umbrella, domestic support for developing its own independent nuclear weapons is high and growing. Scientific research and policymakers have increasingly emphasized the risks of new proliferation cascades if South Korea were to cave to these pressures and weaponize, but we do not yet have a complete picture of what motivates this increasing demand or what to do about it. This work contributes by considering how North Korea’s choice of nuclear posture – not just its possession of nuclear weapons – can affect public threat perceptions in South Korea, and in turn generate pressures to proliferate. Using an original survey experiment, we find that the South Korean public’s fears of different military threats are highly sensitive to North Korea’s choice of nuclear posture, and that these fears in turn increase public support for South Korea developing its own independent nuclear arsenal. However, the effects of posture on all types of threat perceptions disappear when respondents are asked to imagine a nuclear-armed South Korea, indicating the public believes an independent South Korean arsenal can effectively mitigate its security fears. Taken together, this work suggests that state’s nuclear choices continue to influence regional security and proliferation dynamics long after breakout.
Dr. Ariel Petrovics is research associate and former Assistant Research Scholar and Professor at University of Maryland’s School of Public Policy and a Non-Resident Fellow at the Quincy Institute. Her research examines the effectiveness of foreign policy strategies on nuclear proliferation and international security and has been published by the Journal of Global Security Studies, the Washington Quarterly, Bulletin of Atomic Scientists, and Texas National Security Review, among others. She is coeditor and contributing author of Atomic Backfires: Why Nuclear Policies Fail (with MIT Press, fall 2025). She earned her PhD in Political Science from the University of California, Davis and has held positions as a Stanton Nuclear Security Postdoctoral Fellow and Research Fellow with Managing the Atom and International Security at Harvard’s Belfer Center for Science and International Affairs, the IGCC Herbert York Fellow, and a predoctoral research associate at the Lawrence Livermore National Laboratory’s Center for Global Security Research. Her work has been supported by the Stanton Foundation, the Charles Koch Foundation, and the Carnegie Corporation of New York.
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