STEPHEN HERZOG, LAUREN SUKIN
Earlier this month, South Korean President Yoon Suk-yeol set off alarms. In an off-the-cuff remark, he warned that Seoul might need to develop nuclear weapons—or demand redeployment of U.S. nuclear arms to the Korean Peninsula—to counter North Korean nuclear threats. In doing so, Yoon spotlighted a popular view once reserved for hawkish commentators, defense intellectuals, and former military officials. Keeping nuclear weapons out of South Korea will ultimately be a U.S. responsibility that requires addressing both the deteriorating security environment and the domestic drivers underlying Yoon’s statement.
NUCLEAR POPULISM
Yoon’s announcement should be popular at home. Polling from last year shows 71 percent of South Koreans believe their military should acquire the bomb. Surveys from previous years have shown similar numbers, but mainstream politicians have largely stayed away from advocating proliferation.
Stephen Herzog is a senior researcher in nuclear arms control at the Center for Security Studies of ETH Zurich, the Swiss Federal Institute of Technology, and an associate of the Harvard Kennedy School’s Project on Managing the Atom.
Yoon’s nuclear rhetoric also made headlines during the 2022 presidential election, when a nuclear South Korea became a mainstay of his conservative People Power Party’s platform. During the campaign, Yoon called for South Korea to host U.S. nuclear weapons before he then backtracked, saying this could violate the Nuclear Non-Proliferation Treaty (NPT).
Now, rapidly increasing North Korean missile testing, a growing Chinese arsenal, and the fallout from Russia’s invasion of Ukraine have worsened Seoul’s security environment.