Conventional capabilities, nuclear ambiguity key to U.S. extended deterrence, say experts

Nuclear policy experts speaking at a Thursday afternoon roundtable emphasized that South Korea's conventional capabilities and U.S. ambiguity regarding nuclear weapons use form the core of Washington’s extended deterrence commitment to Seoul.

Nuclear policy experts Adam Mount, second from left, and Toby Dalton, third from left, speak at a roundtable discussion moderated by Korea Pro Editorial Director Kim Jeong-min, far left, at the Four Seasons Hotel in central Seoul on Thursday afternoon. [MICHAEL LEE]

Nuclear policy experts speaking at a Thursday afternoon roundtable in central Seoul emphasized that South Korea’s “robust” conventional capabilities and U.S. ambiguity regarding nuclear weapons use in response to a North Korean attack form the core of Washington’s extended deterrence commitment to Seoul.

The discussion, held under the theme of “Answering nukes with nukes? US Extended Deterrence and Misconceptions in Seoul,” was hosted by NK News analysis group Korea Pro and featured remarks by Adam Mount, senior fellow at the Federation of American Scientists (FAS), and Toby Dalton, co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace.

Dalton, who previously worked as a senior policy advisor in the U.S. Energy Department’s Office of Nonproliferation and International Security, noted that the Washington Declaration between South Korean President Yoon Suk Yeol and U.S. President Joe Biden had “gone a long way” to address Seoul’s “assurance problem” by committing more deployments of U.S. strategic assets to South Korea, but also said the “new status quo” on extended deterrence between the allies remains “fragile,” especially if Pyongyang carries out its long-anticipated seventh nuclear weapons test, which he said “could spark a renewed sense of crisis” in Seoul.

Dalton attributed the fragility of South Korean confidence in U.S. assurances to differences in how the allies believe U.S. nuclear weapons should be used in response to a potential attack by North Korea.

“The U.S. view is that its policy to ‘end the regime’ [of North Korean leader Kim Jong-un] if it uses nuclear weapons should be sufficient assurance, but the South Korean view appears to advocate for a more direct U.S. commitment to respond with nuclear weapons,” he said.

Dalton also noted that “most foreign American policy experts and practitioners believe that ambiguity [regarding potential use of nuclear weapons] is the right policy.”

Mount, who has directed focus groups exploring how to handle a nuclear-armed North Korea at both the Council on Foreign Relations and the FAS, also noted that the South Korean government “have recommended a more explicit alliance policy” that entails U.S. use of nuclear weapons, but that U.S. policy is to respond effectively and overwhelmingly, but only with nuclear weapons “if necessary.”

“The U.S. commitment to end the [North Korean] regime if it uses nuclear weapons is not a commitment to use nuclear weapons,” he said, adding that U.S. officials believe that conventional capabilities are currently “sufficient” to accomplish that objective.

Mount also explained that the U.S. policy of ambiguity is intended to not only maintain deterrence credibility “by complicating Kim Jong-un’s calculus of potential outcomes” should he contemplate a nuclear attack, but also to preserve “flexibility” of a U.S. president in a contingency where the use of nuclear weapons is under consideration.

However, Mount emphasized that the U.S. preference for flexibility “is not flexibility about whether or not to defend South Korea,” but is rather about “the best way” to protect the country in the face of a North Korean attack.

“There is no flexibility about whether or not the United States should pack up and go home after a [North Korean] nuclear weapons attack,” Mount said. “If anything, the United States would be more invested and assertive about defending South Korea.”

While Mount acknowledged the U.S. commitment and requirement to consult with South Korea in a contingency involving nuclear weapons as an innovation of the Washington Declaration, he noted that the two allies would need to rehearse and practice effective communications to prepare for such a possibility.

In their response to questions from participants at the roundtable, both experts agreed that the “core” of Washington’s security commitment to Seoul is South Korea’s conventional power, augmented by U.S. nuclear and conventional force.

In his comments, Dalton noted that U.S. extended deterrence was “strong” partially because South Korean conventional capabilities are “remarkably robust.”

“As North Korean conventional forces have atrophied while the regime directs more resources on its strategic capabilities, the alliance has adapted its stand-off capabilities, which is where it really shines these days,” Mount said.

BY MICHAEL LEE [lee.junhyuk@joongang.co.kr]