Former U.S. Nonproliferation Official Cautions South Korea Against Talk of Pursuing Nuclear Weapons

For Immediate Release: Jan. 12, 2023

Media Contacts: Daryl G. Kimball, executive director, 202-463-8270 ext 107; Kelsey Davenport, nonproliferation policy director, 202-463-8270 ext. 102

(Washington) —South Korea's president Yoon Suk Yeol said today that if the North Korean nuclear and missile threat continues to grow, his country might press the United States to deploy nuclear weapons on the Korean Peninsula, or else build nuclear weapons itself.

“It’s possible that the problem gets worse and our country will introduce tactical nuclear weapons or build them on our own,” Mr. Yoon said. “If that’s the case, we can have our own nuclear weapons pretty quickly, given our scientific and technological capabilities.”

In response, board chair of the independent Arms Control Association Thomas Countryman said the costs and risks of nuclear weapons in South Korea would outweigh, by far, any perceived benefit.

"The costs and risks of reintroducing U.S. nuclear weapons in South Korea for the first time since 1991, or even worse, breaking out the 1968 nuclear Nonproliferation Treaty (NPT), would outstrip, by far, any perceived military or security value," Countryman warned.

"South Korea’s international reputation would suffer a serious blow, with real economic and political consequences. Its alliance with the U.S. would have to be transformed in ways that would be, in my opinion, extremely negative for the Republic of Korea's security and for international peace and security,” Countryman said.

South Korea certainly has the technical capability to develop nuclear weapons and missiles to deliver them, but it is legally bound as a non-nuclear weapon state party to the 1968 nuclear Nonproliferation Treaty (NPT) not to do so. The reintroduction of nuclear weapons there would also very likely prompt a dangerous action-reaction cycle involving North Korea and China.

"The nuclear Nonproliferation Treaty is not just a legal technicality. It is the cornerstone of a global security system that has served the Republic of Korea and the world well for over 50 years," Countryman stressed.

Mr. Countryman was the acting Undersecretary of State for Arms Control and International Security until January 2017 and served as Assistant Secretary of State for International Security and Nonproliferation from 2011 to 2016.  He was a senior member of the U.S. delegation to the 2022 NPT Review Conference.

"Withdrawal from the NPT by the government in Seoul would not be cost-free. It would severely damage the Republic of Korea's (ROK) reputation and its economic interests, and it would fundamentally change the U.S.-ROK alliance. It would damage that relationship in economic, political, and security terms. It would severely damage the global effort to prevent the further spread of nuclear weapons. No U.S. President will ever say he is indifferent to a ROK nuclear weapons program,” Countryman noted.

“The idea of reintroducing U.S. nuclear weapons to the Republic of Korea (ROK) might provide some short-term domestic political value, but it would not improve the South's security against North Korea's growing nuclear and missile capabilities, which are backed up with the iron-clad U.S.-ROK defense alliance," Countryman said.

"Even worse would be for the ROK to begin its own nuclear weapons program. A violation of, or withdrawal from, the Nonproliferation Treaty would trigger the kind of international condemnation that the DPRK has invited upon itself," Countryman cautioned.

"The far more effective approach for the ROK is to maintain a strong alliance and work closely with the United States and Japan to pursue pragmatic diplomacy to halt and later reverse North Korea's nuclear buildup, and to ease tensions on the peninsula," he said.