The Peninsula

U.S.-ROK Alliance Consultative Mechanisms: Strengthening Deterrence, Providing Reassurance, Facing an Enduring Challenge

This piece is one of 12 contributions to KEI’s special project on South Korea’s nuclear armament debate that will run on The Peninsula blog over the next month. The project’s contributors include young, emerging, and mid-career voices, examining the debate from a historical, a domestic, and an international perspective. On Wednesday, March 15, KEI will host a conference featuring our various contributors’ work at our Washington, D.C. office and launch a compilation of all the pieces in a single, special KEI publication.

“We go together” is a pronouncement often made in the Republic of Korea (ROK or South Korea) – United States (U.S.) alliance. To realize this unity between the two allies, the alliance has a myriad of diverse consultative mechanisms. These range from presidential summits that have established joint visions for the alliance to crisis management teams that have designed combined operations in response to provocations. The mechanisms collectively reflect the breadth and depth of ROK-U.S. security cooperation, as well as the increasingly complex strategic environment in which the alliance operates. Their establishment and evolution provide context to better understand ROK discourse on nuclear armament.

The alliance’s consultative mechanisms are a manifestation of the commitment by South Korea and the United States to mutual defense and a signal of the U.S. pledge to provide extended deterrence for the ROK. They are also tools of alliance management. “Consultation” encompasses a range of activities, including but not limited to the exchange of perspectives, collective deliberation, transactional negotiation, and post-decision notification. The way these mechanisms are used, as well as the content of the consultations, both reflect and influence intra-alliance dynamics. Across time, the exchanges shape the culture of the alliance and its members—including the way in which each country understands deterrence dynamics.[1]

This paper examines alliance consultative mechanisms focused on countering North Korea’s nuclear and weapons of mass destruction (WMD) and on U.S. nuclear extended deterrence. It assesses how these consultative mechanisms adapted to changes in the North Korean threat, represented the views of each ally on deterrence and reassurance, and facilitated alliance cohesion in certain areas of policy. It will also identify where progress has been limited, leaving an enduring challenge that left unaddressed will fuel the nuclear armament debate among the policy elite in South Korea.

[1] Observations of the author (ROK national) who, as a strategist/international specialist employed by U.S. Forces Korea (USFK) and in support of various teams in the Office of the Secretary of Defense (OSD), was part of working-level ROK-U.S. operational and policy consultations from 2013-2018.

A Dialogue to Address Emerging Deterrence Challenges

In committing to provide extended deterrence for South Korea, the United States draws on the full range of its military capabilities, including its nuclear weapons. This was the case even before North Korea posed a nuclear threat; as early as 1950 the United States conspicuously avoided dismissing nuclear use as an option in the Korean War. However, official dialogues with South Korea regarding U.S. extended nuclear deterrence only began in 2010, following North Korea’s second nuclear test and the launching of the Unha-2 long-range missile. These events inspired concern both in South Korea and the United States about emerging deterrence challenges – alliance de-coupling and a stability-instability paradox – that a nuclear North Korea with long-range missiles could pose.

Through the 2010 establishment of the Extended Deterrence Policy Committee (EDPC) with South Korea and the Extended Deterrence Dialogue (EDD) with Japan, the United States aimed to comprehensively strengthen the regional deterrence architecture in Northeast Asia and bolster alliance cooperation. The EDPC consultative mechanism was also an effort to address ROK security concerns and make the U.S. pledge of extended nuclear deterrence “more concrete.”

These concerns included the ROK government perception that the U.S. “declaratory policy commitment was insufficient” to deter North Korea. This ROK judgement was based partly on the alliance’s failure to deter North Korea’s 2010 sinking of the ROK Navy ship Cheonan and its shelling of Yeonpyong Island—aggression that was considered likely to continue in the context of North Korea’s leadership transition and an increasingly credible nuclear shadow.

South Korea sought greater understanding of the U.S. commitment to provide nuclear extended deterrence, given President Obama’s pledge to reduce the role and number of U.S. nuclear weapons amid an increasing North Korean threat. The ROK government also sought greater visibility into U.S. nuclear planning, decision-making, and operations—all of which remained opaque to it, despite South Korea’s vital national security interests depending on these U.S. activities.

Through joint studies and analyses, in addition to bilateral table top exercises (TTXs), the EDPC provided a mechanism to exchange views on the North Korean nuclear threat and to design a more comprehensive collective approach to deterrence across armistice and wartime. This resulted in the 2013 ROK-U.S. Tailored Deterrence Strategy (TDS)—a “strategic framework” that “strengthens the integration of alliance capabilities to maximize their deterrence effects.” The strategy signaled bilateral agreement on leveraging not only the U.S. nuclear umbrella, but also the conventional strike and missile defense capabilities – of both the United States and South Korea – to deter North Korea’s nuclear and other WMD threats.

Specifically, the TDS identified distinct U.S. and ROK assets to be used together in support of three deterrence-focused lines of effort: encouraging restraint, denying the benefits and raising the costs of North Korean nuclear, WMD, or ballistic missile use. In this way, the TDS was meant to guide bilateral planning and force development, to meet the changing deterrence challenge North Korea posed. South Korea and the United States also agreed on “Concepts and Principles for Comprehensive Alliance Counter-Missile Operations” (also known as the “4D Strategy” to detect, disrupt, defend, and destroy) through another consultative mechanism, the Counter-Missile Capabilities Committee (CMCC). This strategy further facilitated efforts to achieve “synergies and efficiencies” in the combined force through better coordination of capabilities South Korea and the United States were planning separately to develop.

The TDS and the 4D strategy are examples of how alliance consultative mechanisms can reorganize disparate national efforts, shape thinking, and forge a common outlook. They induced a broadening of alliance efforts traditionally focused on deterrence by punishment (or cost imposition), to also include efforts to bolster deterrence by denial. This helped advance an alliance position on the need for layered missile defense. TDS and 4D also provided the United States a way to encourage South Korea to think of means and ways beyond U.S. nuclear retaliation threats to counter potential North Korean nuclear strategies. It also facilitated a framework through which South Korea could later explain how its “3K” system of non-nuclear strategic capabilities contributed to the alliance’s overall deterrence posture.

Adapting Consultations to Reflect a Transformed Threat

In 2015, the EDPC and CMCC merged to form the Deterrence Strategy Committee (DSC). This reflected agreement to better integrate ROK, U.S., and collective alliance efforts to deter the evolving North Korean threat. The focus on deterrence instead of extended deterrence in the new name of the committee was deliberate. This reflected the aim of both allies to underscore the contribution of ROK capabilities, but also to better incorporate them into realizing a combined deterrence posture that complemented U.S. extended deterrence and the nuclear umbrella. The merger was also a response to North Korea’s progress toward miniaturizing its nuclear warheads and marrying them to missiles, which provided a reason for the alliance to approach deterring the threats of North Korean nuclear weapons and missiles together.

The DSC worked to foster mutual understanding of the threat, as well as the capabilities each ally would contribute to a collective posture aimed at deterring North Korean nuclear use. Committee members together visited bases in the United States and South Korea to see U.S. strategic assets and alliance conventional systems firsthand. By showing U.S. capabilities such as the B-52, Ground-Based Interceptor (GBI) Launchpad, Minuteman III intercontinental ballistic missile (ICBM), and a nuclear-powered ballistic-missile submarine (SSBN) the United States sought to reassure South Korea by making the U.S. capacity to extend nuclear deterrence more tangible. Additionally, the United States and South Korea discussed in TTXs “a number of feasible scenarios involving North Korea’s nuclear weapons, to study and understand, in peacetime rather than crisis, the different perspective, priorities, factors, and considerations” that their military and political leaders might face in the future.

In addition to raising awareness of each other’s perspectives, in 2016 South Korea and the United States endorsed through the DSC the 4D Concepts and Principles Implementation Guidelines (CPIG). For South Korea, emphasis on realizing a bilateral agreement that underscored “implementation” was an area of much needed progress. South Korea continued to not only seek a more concrete understanding of U.S. strategic capabilities on which it depended as a non-nuclear ally, but also to establish greater agency in U.S. nuclear deterrence operations amid a rapidly transforming North Korean nuclear threat.

Because the practice of deterrence relies as much on other tools of national power, such as diplomacy and economic statecraft, as on military might, South Korea and the United States also established in 2016 an additional consultative mechanism, the high-level Extended Deterrence Strategy and Consultation Group (EDSCG). This body raised official consultations of the DSC at the U.S. deputy assistant secretary level to the assistant secretary level in the United States, and had as its co-chairs representatives from the U.S. departments of defense and state, with counterparts from the ROK defense and foreign ministries. The EDSCG conducted “comprehensive and in-depth discussions on strategic and policy issues regarding extended deterrence against North Korea, including how to better leverage the full breadth of national power – using diplomacy, information, military, and economic elements.”

After a hiatus of five years, reflecting the approaches of both the Moon and Trump administrations to deterrence, extended deterrence, and alliance management, in 2022 the Yoon and Biden administrations reactivated the EDSCG bilateral consultation mechanism. Reiterating the “U.S. unwavering commitment to provide extended deterrence for the ROK,” the EDSCG and the DSC have continued work on “how best to tailor” alliance responses to the evolving North Korean threat.

The establishment and evolution of these consultative mechanisms reveal how the alliance has progressed in realizing a more combined and comprehensive deterrence posture. The EDPC, CMCC, DSC, and EDSCG helped forge agreement on the desirability of a holistic approach to deterrence. The changing design of the bilateral consultative mechanisms also reflects how South Korea and the United States adapted to North Korea’s expansion and integration of its nuclear and missile capabilities, and enabled greater bilateral inter-agency coordination.

The Enduring Challenge of Integration and Cooperation in Deterrence

The persistence of ROK security concerns and discourse on the potential need for South Korean nuclear armament should not be surprising. The deterrence and reassurance challenge for the alliance continues to be formidable. It is important to recognize ROK and U.S. progress in realizing a more comprehensive approach to deterrence, in advancing their extended nuclear deterrence consultations, and in establishing policy frameworks to guide more effective deterrence operations. However, amid troubling changes in the North Korean nuclear threat and security environment, it is equally important to acknowledge where consultative mechanisms have previously been limited. Moving forward, it will be important to address the enduring challenge of incorporating U.S. nuclear operations into other efforts of alliance cooperation.

It is noteworthy that progress in strengthening the alliance’s deterrence posture has predominantly involved greater integration of ROK advanced conventional assets, leveraging ROK and U.S. non-nuclear capabilities, and considering more non-military activities. Much less has been achieved in integrating South Korea in U.S. nuclear operations or adapting the U.S. strategic nuclear posture to address the established nuclear threat North Korea now poses. Failure to address this lack of change amid the increasing nuclear challenges the alliance faces will only fuel debate in South Korea about nuclear armament. Simply, more of the same consultations and demonstrations of U.S. strategic assets, without greater ROK integration, will no longer meet deterrence and reassurance requirements.

This is not to dismiss the importance of regular consultations, current deployments, or exercises. Nuclear crisis may develop in countless and unpredictable ways. Given this uncertainty, the institutionalization of consultation processes and the pre-crisis discussions of the DSC and EDSCG are tangible tools that should support an adaptive alliance nuclear posture. This too is a requirement for alliance cohesion and should strengthen deterrence.

However, policy discussions to foster shared understanding of the threat and a common approach to deterrence, though critical are insufficient. If nuclear deterrence is to be effectively waged, it must not remain only a subject of policy discussions but must be implemented through active preparations that raise the credibility of declaratory statements. The DSC and EDSCG should include review and assessment of policy implementation. Policy should guide but also support, and be informed by, the forces tasked to wage deterrence and operate against nuclear threats.

To address this policy-operations divide, the alliance should work to better integrate U.S. nuclear and alliance conventional planning. South Korea and the United States should better prepare ROK forces to operate in support of U.S. nuclear operations and to be capable of conducting missions after nuclear use by either North Korea or the United States. Integration should go both ways. Alliance work on coordinating how ROK non-nuclear strategic forces can be used to enhance deterrence is important, but so too is incorporating U.S. nuclear assets into an alliance posture and strategy focused not only on “fight tonight” readiness but also on active operations to “deter today.”

S. Paul Choi is Principal (on sabbatical 2022-23) at StratWays Group, a geopolitical risk advisory in Seoul. The views expressed here are the author’s alone.

Photo from U.S. Secretary of Defense’s photostream on flickr Creative Commons.