Yoon, Biden and nuclear weapons

With the new arrangement, Korea could become the most influential. And that is appropriate given the growing challenges on the Korean Peninsula.

Michael GreenThe author is CEO of the U.S. Studies Centre at the University of Sydney and Henry A. Kissinger Chair at the Center for Strategic and International Studies (CSIS).

President Yoon’s summit with President Biden at the end of April was a big success despite the embarrassing leaks of U.S. intelligence analysis. Overall, the summit advanced cooperation on semiconductor export controls, support for democracy, and regional diplomacy. Most Americans will remember the summit because of President Yoon’s credible rendition of “American Pie.” He will not be asked to join BTS any time soon, but he reminded Americans that Korea is the land of K-Pop and a pop-culture powerhouse.

In geopolitical terms, the most significant part of the summit was probably the intense focus on nuclear weapons. In the joint press conference President Yoon stressed that: “our two countries have agreed to immediate bilateral presidential consultations in the event of North Korea’s nuclear attack and promised to respond swiftly, overwhelmingly, and decisively using the full force of the alliance including the United States’ nuclear weapons.” Biden stressed the American commitment to extended deterrence (sometimes called the U.S. “nuclear umbrella”), including language in the two leaders’ joint statement reaffirming that the U.S. “commitment to the ROK and the Korean people is enduring and ironclad, and that any nuclear attack by the DPRK against the ROK will be met with a swift, overwhelming and decisive response.” In return, Yoon reiterated Korea’s commitment to the Non-Proliferation Treaty and the two leaders agreed to set up an Assistant Secretary-level Nuclear Consultative Group to “discuss how to plan for nuclear contingencies and cooperate on the Alliance’s approach to nuclear deterrence.”

No U.S. summit with the NATO, Japan or Australia has featured such a major focus on nuclear weapons for years. What is happening?

U.S. President Joe Biden surprises President Yoon Suk Yeol with a guitar signed by singer Don McLean in the State Dining Room of the White House in Washington, Apr. 26, following the State Diner. American Pie, by McLean, is one of Yoon’s favorite songs. [AP/YONHAP]

The most obvious factor is North Korea’s relentless strengthening of its nuclear weapons programs and refusal to engage in any diplomacy on disarmament. With over 100 missile tests this past year alone and diversification of missile systems to include solid fuel engines and submarine-launched missiles, in addition to credible reports of greater miniaturization of warheads, Pyongyang is clearly aiming not just for a minimal “deterrent” to hold the United States, South Korea or Japan at risk — but also towards a survivable deterrent and that can be used in conventional warfighting scenarios. The test of an ICBM-like missile capable of delivering warheads to the United States raises additional fears in South Korea of “decoupling” and questions of whether an American President would be willing trade Los Angeles to defend Seoul.

These same developments raise questions in Japan or Australia about the credibility of extended deterrence but very large majorities in both those countries strongly oppose the independent development of nuclear weapons. The opposite is true in South Korea, where large majorities in polls often express support for nuclear weapons and prominent political figures advocate this option without facing significant criticism as they would in Japan or Australia.

Yoon and Biden had to manage these concerns, and for the Yoon government, the best option for now is to gain greater influence over American decision-making on nuclear weapons and extended deterrence rather than respond to popular calls for independent nuclear weapons. Superficially, independent nuclear weapons may seem appealing to a people who would prefer more independent control of their own nation’s security, but the Yoon government knows that would be a dangerous and self-isolating path. Korean nuclear weapons would set a dangerous precedent by violating the Non-Proliferation Treaty. For that reason alone, future U.S. administrations and Congresses would almost certainly oppose it (even if Donald Trump once mused in 2016 that he personally did not care if Korea or Japan developed nuclear weapons). Even if Washington were inclined to support the move, close allies like Japan, Australia, and NATO would make it impossible for Washington to win support from Nuclear Suppliers Group which would then force Seoul to acquire necessary technologies, uranium, and other inputs clandestinely. Korea would then be isolated diplomatically from all of its most important allies and trading partners. And the diplomatic friction would cast even greater doubt on the U.S. nuclear deterrent, which would still be far more powerful in North Korean eyes unless Pyongyang saw discord between Seoul and Washington.

There could be interim options short of independent nuclear weapons. The United States could agree to so-called “dual keyed” American tactical nuclear weapons that would be stationed in Korea and jointly controlled by both militaries so neither could launch without the others’ approval. Or the United States could redeploy U.S.-controlled tactical nuclear weapons for the first time since President George H.W. Bush withdrew them in 1991. My own view is that these options merit debate and consideration, but for now the down-side risks still far outweigh the advantages. The main two advantages would be to give Seoul and Washington increased tactical options and to signal elevated deterrence commitments to adversaries. However, the downside risk would be significant since these forward-deployed assets could be more easily targeted than submarine and air launched systems and the potential for major domestic opposition in Korea could weaken the intended deterrence signal by sowing discord in the alliance.

For now, Yoon and Biden have made the right choice with the new Nuclear Consultative Group. The group will ensure a greater Korean input in American thinking on deterrence strategy and could be the venue where the interim options described above might be examined someday — depending on North Korea and Chinese developments. The consultative group will also arm Seoul with arguments it needs to reassure the Korean people and mute criticism of the U.S. deterrent while providing a forum to ensure Washington keeps its declaratory policy and development and deployment of systems optimized for the Korean Peninsula. The announcement that the U.S. Navy will send its first nuclear armed submarine to South Korea for the first time since the Cold War is an example of the kind of careful operational deployments and signals the consultative group can develop.

Some have argued that the consultative group is still weaker than NATO’s similar group, but that is wrong. Senior officials privately tell me that in the past three Nuclear Posture Reviews by the U.S. government — during the Obama, Trump, and Biden administrations — the most influential allied voices were those of Japan, Britain, France, and Korea … in that order. With the new arrangement, Korea could become the most influential. And that is appropriate given the growing challenges on the Korean Peninsula.