Opportunities and Challenges for South Korea-U.S. Cooperation in the Indo-Pacific
from Asia Unbound, Asia Program, and Bolstering U.S.-South Korean Cooperation to Meet the China Challenge

Opportunities and Challenges for South Korea-U.S. Cooperation in the Indo-Pacific

The first workshop for the project on Bolstering U.S.-South Korean Cooperation to Meet the China Challenge examined the opportunities and obstacles for enhanced U.S.-South Korean policy coordination in the Indo-Pacific region.
The 23rd ASEAN-South Korea Summit was held in Phnom Penh, Cambodia on November 11, 2022.
The 23rd ASEAN-South Korea Summit was held in Phnom Penh, Cambodia on November 11, 2022. (Cindy Liu/Reuters)


Now that South Korean President Yoon Suk Yeol has demonstrated his willingness to support the rules-based order in the Indo-Pacific with the United States and like-minded countries, other regional countries are observing cautiously whether South Korea can fulfill such a commitment. Despite the challenges ahead, the Yoon administration’s pivot to the Indo-Pacific reflects not only its grave concern over the authoritarian revisionism spreading across the region, but also its foreign policy goal of becoming a global pivotal state. South Korea’s Indo-Pacific Strategy, which was released in December 2022, will be instrumental in materializing this foreign policy vision. 

South Korea’s new Indo-Pacific Strategy can be understood as an attempt to broadly align with U.S. strategic interests beyond the Korean Peninsula. The Indo-Pacific is a strategic system in which the United States and like-minded countries are attempting to resist authoritarian revisionism by complementing the existing hub-and-spoke regional alliance architecture with bespoke, ad hoc coalitions that share common threats, interests, and values. Whether the inclusion of South Korea can supplement that networked regional architecture will be critical in shaping the trajectory of allied cooperation between South Korea and the United States, as well as the larger geopolitics of the Indo-Pacific.

Summary of the CFR Workshop

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The Council on Foreign Relations held a virtual workshop on June 7, 2023, on “U.S.-South Korea Policy Coordination Toward the Indo-Pacific.” The workshop’s major takeaways include the following:

  • The success of the new South Korea-U.S. Nuclear Consultative Group (NCG) in responding to the burgeoning military threat of North Korea will be essential for South Korea-U.S. cooperation in the Indo-Pacific. While South Korea has demonstrated its willingness to expand its diplomatic horizon across the Indo-Pacific, its foremost priority remains deterring North Korea’s threat, dissuading its provocations, and maintaining stability on the Korean Peninsula. Therefore, establishing the South Korea-U.S. NCG, as stipulated in the Washington Declaration, reflects the U.S. understanding that providing reassurance to South Koreans over the North’s nuclear threat is imperative. Indeed, as the North’s missile capability has become more sophisticated and diversified, South Koreans have insisted on developing indigenous nuclear weapons or redeploying U.S. tactical nuclear weapons as during the Cold War. Therefore, against this backdrop, the Washington Declaration elaborates measures—such as strengthening U.S. extended deterrence by enhancing the visibility of U.S. strategic assets such as ballistic missile submarines— which are expected to reduce the possibility of a preemptive attack on the South from the North. Additionally, the NCG can serve as an institution in which the two allies discuss and jointly conduct military operations in the event of a nuclear crisis on the Korean Peninsula even after the Wartime Operational Control is transferred to the South. In that sense, the NCG will be instrumental in tightening allied coordination against the North.
  • South Korea and the United States need to share their view on China and other revisionist countries. While the Yoon administration emphasizes the importance of the rules-based order in the Indo-Pacific, it does not seek to antagonize or balance against China. As China is one of South Korea’s largest trade partners, the scope and level of de-risking measures could potentially not meet U.S. expectations.
  • Cooperation in science and technology will be important. U.S.-China competition is not just about relative military strength or trade volume; it also encompasses innovation in the domains of science and technology. Artificial intelligence and quantum technology will be major sources of reordering the global balance of power in the future.
  • Both South Korea and the United States need to explore more areas of cooperation. In particular, South Korea’s commitment to values-driven diplomacy, as shown in the case of holding the Summit for Democracy, can complement that of the United States, generating more synergistic efforts to reverse democratic declines and garnering support from like-minded countries.

Opportunities for Allied Cooperation

From the beginning, the Yoon administration has attempted to claim its position within the regional architecture. First, as minilateral coalitions flourished during the last few years, Seoul exhibited its willingness to join them. Most of all, President Yoon has demonstrated South Korea’s willingness to join the Quad (the informal quadrilateral security dialogue between the United States, Australia, India, and Japan) since his inauguration, which has contrasted with his predecessor Moon Jae-in’s reluctance to participate. However, as the momentum for participation seems to have passed, Yoon could try to find overlapping areas of cooperation prioritized by Quad member states.

Because of the missed opportunity with the Quad, the Yoon administration has actively joined other regional coalitions and aligned with U.S. interests in the Indo-Pacific. In addition to joining the Indo-Pacific Economic Framework in 2022, South Korea joined the Asia-Pacific Four to address Russia’s invasion of Ukraine together with Australia, Japan, and New Zealand. Furthermore, Chip 4, which is the alliance proposed by the United States that includes Asian semiconductor powers South Korea, Japan, and Taiwan, is an attempt to keep China’s emerging chip industry at bay. The Yoon administration further suggested its willingness to take part in the Partners in the Blue Pacific—a recent informal grouping comprised of South Korea, the United States, Australia, Canada, Japan, and the United Kingdom—and scale up its development assistance to Pacific Island countries and strengthen their resilience. Most of all, South Korea’s restored relationship with Japan is expected to provide wider opportunities for South Korea to engage in the Indo-Pacific. Besides, the two countries align in their interest to secure the rules-based order and resist revisionism, which is likely to expand South Korea’s role in the region commensurate with its capabilities.

Altogether, South Korea’s willingness to join those thriving platforms provides opportunities to expand its network with regional countries and understand their interests and threat perception, which will be instrumental in developing its approach to the Indo-Pacific.

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Converging on De-risking China

South Korea’s attitude to China is gradually aligning with that of the United States as the Yoon administration emphasizes the importance of a rules-based order. During the Moon administration, China was regarded as an important partner for economic cooperation as well as a facilitator for sustaining inter-Korean dialogue. As the Moon administration assumed that improving inter-Korean relations was instrumental to reconciling U.S.-North Korea relations, the diplomatic role of China in this process was highly appreciated. However, the current Yoon administration seems to perceive the performance of China in both imposing sanctions and encouraging dialogue with the North as futile, given that China’s priority on the Korean Peninsula is maintaining balance vis-à-vis the United States, rather than supporting U.S.-South Korean denuclearization efforts. Whether South Korea will more closely align with U.S. efforts to counter China seems to depend on China’s choices in the foreseeable future.

However, this does not mean that South Korea will undertake explicit balancing or antagonizing China. China is still South Korea’s largest trading partner and one of the major actors in resolving the North Korea issue. This understanding is reflected in South Korea’s Indo-Pacific strategy, which emphasizes its inclusive nature and does not exclude any countries in the region willing to secure the rules-based order. Although the Yoon administration agrees that peace and stability in the Taiwan Strait are important to regional and global peace—as well as to South Korea—that does not necessarily mean that South Korea’s China policy can include a hard-balancing component. Instead, it simply demonstrates South Korea’s concern that any crisis escalation across the Taiwan Strait could not be resolved without inflicting collateral damage to U.S. allies and partners in the region.

In this vein, South Korea could wish to de-risk rather than de-couple with China, which would strike a better balance between national security and economic interests. While the Joe Biden administration initially took a strong stance on balancing China—especially in terms of advanced technologies such as artificial intelligence, quantum computing, and related supply chains—President Biden recently mentioned during the Group of Seven (G7) Summit that the U.S. strategy toward China is de-risking, not decoupling. This statement was welcomed by middle powers, including South Korea, who cannot easily reshore their manufacturing capacity in China or reorganize supply chains which are heavily dependent on China. Nonetheless, South Korea would like to work with the United States and regional partners to deter China from using economic coercion to force regional countries into political concessions, such as by coordinating export controls or anti-coercion instruments as discussed during the 2023 G7 Summit.

Nonetheless, the looming risk of a conflict over Taiwan and the South China Sea, as well as Chinese encroachment into the Global South, cannot be left unaddressed. Given the Indo-Pacific’s maritime nature, South Korea’s cooperation with the United States would likely emphasize delivering development assistance; increasing maritime confidence-building such as port visits and personnel exchanges between navies and coast guards; and establishing a hot line between naval ships. At the operational level, South Korea is gradually expanding the scope of its information sharing and joint exercises. 

Challenges From the Domestic Front  

One of the primary challenges that South Korea could face in implementing its Indo-Pacific Strategy in concert with the United States is likely to come from the domestic front. The Yoon administration’s efforts to connect with regional countries have been well sequenced. Reinforcing the South Korea-U.S. alliance and restoring the South Korea-Japan relationship bodes well for revitalizing South Korea-U.S.-Japan trilateral relations. Under the Moon administration, South Korea and Japan’s strained relationship was a weak link in the trilateral dynamic; now, it can further serve as a counterweight against North Korea and its revisionist partners. Ultimately, the revitalized trilateral relationship complements the Indo-Pacific security architecture championed by the United States since the Donald Trump administration.

However, under its polarized domestic political environment, South Korea’s commitment to deepening cooperation with the United States could be costly for the Yoon administration to sustain. Public support for the Yoon administration’s cooperation with the United States, especially on developing advanced technologies, reorganizing supply chains, securing mineral resources, and scaling up development assistance toward the Global South, is divided. While those cooperative efforts are geared toward South Korea’s desires to resist Chinese economic coercion, this sense of urgency is not entirely shared by the South Korean public. Some even believe that South Korea is unwillingly being co-opted to the U.S.-China competition. In the same vein, the U.S. Inflation Reduction Act and the CHIPS and Science Act were criticized by some Koreans as America-First policies despite being wrapped in the rhetoric of international norms and secure supply chains. Therefore, the accelerating pace of South Korea’s tightening alignment with the United States and its allies has raised concern.

In this context, President Yoon and the ruling People Power Party’s low approval ratings, which are stagnating below 40 percent, could be another obstacle to sustaining South Korea’s commitment to allied cooperation in the Indo-Pacific. Those approval ratings could seriously affect Yoon’s prospects of winning the National Assembly elections in April 2024. Such an electoral defeat for the ruling party would weaken the driving force behind the current Indo-Pacific strategy and related alignment measures with the United States and regional partners; some speculated that the Yoon administration is rushing its efforts to expand allied cooperation before the election cycle.      

In sum, this partisan understanding of South Korea’s efforts to expand alignment with the United States reveals the extent of political polarization within South Korea. While the foreign policy of most democracies is affected to a degree by partisan politics, the Yoon administration’s low approval rating is likely to further catalyze partisan polarization, potentially making momentum for South Korea-U.S. cooperation untenable.

Categorizing North Korea Into “Indo-Pacific” Issues

In the past, North Korea’s provocations were regarded as a distraction that prevented South Korea from allocating more assets to regional diplomacy in the Asia-Pacific. However, as the North’s missile range now exceeds the Korean Peninsula, it has inevitably become a global issue to which the international community should respond collectively. Additionally, as the Yoon administration’s North Korea policy underlines deterrence and dissuasion vis-à-vis the North, which starkly contrasts with the previous Moon administration’s emphasis on inter-Korean reconciliation, it needs to garner support from international partners. The threat posed by the North justifies South Korea’s effort to restore trilateral cooperation with the United States and Japan, which not only prevents the North from diplomatically exploiting the rift between the three countries but also prepares for practical measures to deter North Korea’s provocations.

The significance of the latest Washington Declaration between South Korea and the United States is that extended deterrence from the United States and South Korea’s conventional deterrence system will be more tightly integrated than in the past, which is expected to provide the South Korean population with stronger security assurances. However, this declaration also indicates that regional confidence in U.S. extended deterrence has been declining, and that the United States and South Korea have managed to find an optimal point of compromise, with the United States strengthening its deterrence capabilities and South Korea silencing calls for nuclear armament. As long as the North’s denuclearization remains unresolved, this argument will likely be a wedge issue within the alliance.


South Korea-U.S. cooperation in the Indo-Pacific presents both opportunities and challenges. While President Yoon’s pivot to the Indo-Pacific and his willingness to complement regional security architecture might be welcomed by the United States, both allies need to communicate their priorities and specific approaches responding to revisionists in the region. The CFR workshop discussion proposed the following.  

  • Deterring and dissuading North Korea’s provocations will be one of the most important steps in expanding South Korea-U.S. allied cooperation measures in the Indo-Pacific. Given that North Korea prefers to consolidate its status as a nuclear state rather than denuclearize, both allies should coordinate measures that make the North’s provocation more costly.
  • South Korea should orchestrate its recently published strategies—the National Security Strategy, the Indo-Pacific Strategy, and the idea of a global pivotal state—in a systematic way so that the domestic consensus and support for South Korea’s foreign policy can be formed and political polarization can be attenuated.
  • As South Korea presents its Indo-Pacific Strategy, it should expand its bilateral and minilateral cooperative efforts with regional partners, which will elevate its global profile.
  • South Korea and the United States should closely communicate and coordinate on de-risking their China policy, which could include curtailing nationalist measures that come at the expense of allies’ and partners’ interests.


South Korea’s venture into the Indo-Pacific, which serves well its foreign policy vision of the global pivotal state, comes with challenges and opportunities. Many opportunities in the regional architecture await Seoul in its attempt to make the Indo-Pacific more resilient against authoritarian revisionism. However, South Korea and the United States’ allied effort to this end comes with risks as well, not to mention managing external challenges such as China and North Korea. It will be important for the allies to minimize unexpected damages inflicted in the process of strengthening economic resilience and preventing any crisis escalation in regional hotspots. Last but not the least, the domestic challenge posed by political partisanship should be managed to support U.S.-South Korean policy coordination in the Indo-Pacific region.

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Kuyoun Chung is associate professor of political science at Kangwon National University.