Future Steps for U.S.-ROK Extended Deterrence Consultations

Defense Secretary Lloyd Austin travelled to South Korea last week to shore up U.S. extended deterrence commitments following President Yoon Suk Yeol’s comments about South Korea possibly developing its own nuclear weapons. The trip marked some forward progress, but there is more that can and should be done. Specifically, to maintain momentum following Secretary Austin’s trip, the administration should do the following: develop a multiyear plan for integrating more tabletop exercises (TTX) and scenario-based discussions into consultations, conduct a classification review, develop a joint crisis management playbook, and better prepare for future proliferation scenarios.

Secretary Austin and Minister of National Defense Lee Jong-Sup “jointly reaffirmed” measures to enhance the implementation of U.S. extended deterrence” including efforts to “enhance information sharing, joint planning and execution, and Alliance consultation mechanisms.” In their joint press conference, Minister Lee offered insights on what the changes to alliance consultation mechanisms might entail: “We agreed for a close communication between the Republic of Korea and the United States, and all procedures of decision-making, by activating ROK-U.S. crisis management consultation groups at times of North Korean crisis.”  These are important steps forward, particularly with regard to improving understanding of decision-making processes during a crisis, expanding trilateral cooperation and hosting a defense ministerial with key members of the United Nations Command. The administration deserves credit for this and for restarting key consultation mechanisms after they sat dormant for more than five years. But the reality is that President Yoon’s comments caught the administration flat-footed, and there’s a lot more the U.S. government can and should be doing.

Make table-top exercises and scenario-based discussions a regular part of consultations.

While Secretary Austin and Minister Lee ultimately confirmed that the Deterrence Strategy Committee (DSC) TTX will go forward this month, the public back-and-forth over the last few months over whether this TTX was actually happening cannot keep happening. When the DSC meets this month, they should adopt a multi-year action plan that links combined exercises and trainings to joint wargames and TTXs that explore a wide range of crisis scenarios. These scenarios should not only include responses to North Korean use of a low-yield nuclear weapon, but also more complex “opportunistic aggression” scenarios that explore, for instance, coordination and resource constraints if North Korea launches an attack in the midst of a Taiwan contingency. Developing a multiyear action plan will also facilitate more working-level interactions, and help alleviate the pressure to fit everything into existing high-level dialogues.

Direct a classification review.

Within the Department of Defense (DOD), the defense secretary should direct a classification review and task the Office of the Secretary of Defense, the Joint Staff, and United States Strategic Command with reviewing U.S. plans and making recommendations for what more could be released to U.S. allies. Discussing these details with allies are among the most sensitive and difficult conversations. And the reality is there is still a lot of work to do within the department to synchronize planning across combatant commands. But ultimately, implementing Secretary Austin’s integrated deterrence concept will require a deeper level of integration, not just between conventional and nuclear planning, but in how Washington talks to allies about these details as well. Doing so will require a push from the most senior levels to take a much closer look at classification constraints and find ways to release more details going forward.

Develop a joint playbook.

Where it is not possible to share operational plans or employment details, jointly developing a playbook that details each country’s approach to decision-making and what role various counterparts would play in the lead up to and during a crisis can help facilitate greater confidence and trust. It may be especially useful now to ensure both sides understand when and how the new Republic of Korea (ROK)-U.S. crisis management consultation groups Minister Lee referenced would come into play. Such a playbook would also be a useful tool for capturing joint bilateral insights and lessons learned from future TTXs. It could also provide a basis for expanding discussions with other U.S. regional allies, such as Japan and Australia.

Prepare for future proliferation scenarios.

And finally, within the interagency, it is time to think through in much greater detail about the implications and possible response options should U.S. allies decide to pursue nuclear weapons in the future. Too often, this is considered an “over the horizon” issue and the debate about “will they or won’t they” obscures difficult conversations about what the U.S. government would actually do if such a development comes to pass. President Yoon’s comments surprised too many people. The NSC should stand-up an interagency tiger team to better detail the implications of such a decision and outline options and a messaging strategy for the administration. Some of this is no doubt already quietly underway given how quickly President Yoon walked back his remarks. But this requires sustained attention and is not something that should be developed on the fly in the future. At the same time, more expert analysis outside of government is also needed to better inform the broader national security community and public debate of what is at stake. This should include specific examples of how allied proliferation could affect broader alliance commitments and U.S. force posture decisions, how sanctions and Nuclear Supplier Group restrictions might affect a country’s economic outlook and ability to maintain a domestic civilian nuclear power program, as well as how such a decision could affect escalation and regional stability dynamics as well as the broader nonproliferation regime. Having spent the past few decades focused almost entirely on adversary proliferation, the United States lacks both experience and frameworks for thinking through how to navigate an entirely different landscape of allied proliferation.

The security environment has changed significantly since the United States and ROK signed the Mutual Defense Treaty 70 years ago. The steps announced last week to strengthen the alliance and ensure U.S. extended deterrence commitments keep pace with the realities of threats posed by North Korea and China are necessary, but not sufficient. Like it or not, President Yoon’s comments forced the Biden administration’s hand. Going forward, the United States cannot afford to be complacent. As Russia’s invasion of Ukraine has made all too clear, the United States cannot avoid difficult conversations with allies about how to respond to nuclear threats and the possibility of nuclear use. This is not just a U.S.-ROK challenge, and the sooner the administration realizes it is going to have to change the way it plans, consults, and operates with U.S. allies when it comes to nuclear weapons and escalation dynamics, the better.

Kelsey Hartigan is deputy director of the Project on Nuclear Issues and senior fellow with the International Security Program at the Center for Strategic and International Studies in Washington, D.C.

Kelsey Hartigan
Deputy Director, Project on Nuclear Issues and Senior Fellow, International Security Program