The Peninsula

In Brief: The U.S.-ROK Alliance and a Taiwan Conflict

Executive Summary

This project builds upon earlier research tracing U.S.-South Korea signaling on “the importance of peace and stability in the Taiwan Strait.” The current project was based on the premise that there is a significant gap between such diplomatic rhetoric and the U.S.-ROK alliance’s preparedness to navigate an actual conflict between the United States and China over Taiwan and the attendant risk of a simultaneous conflict on the Korean Peninsula.

Through dozens of interviews with U.S. and South Korean current and former government officials, think tank experts, and academics—as well as open-source research—this project shows there has been a lack of substantive alliance discussions about a Taiwan conflict and, thus, a serious lack of preparedness for one; that numerous challenges obstruct such discussions; and that the alliance would face interconnected and complex variables in the event of such a conflict, which amplify existing issues within the U.S.-South Korea relationship but also extend well beyond it.

The Korea Economic Institute of America will publish the full report, titled Siloed No More: The U.S.-ROK Alliance and a Taiwan Conflict at an exclusive hybrid launch event on Monday, March 31 at 2:00 p.m. EST. RSVP by clicking here.

The Evolution and State of U.S.-ROK Alliance Discussions on a Taiwan Conflict

Respondents described notable shifts in alliance signaling on the importance of peace and stability in the Taiwan Strait and the current state of official alliance discussions on a Taiwan conflict. Their observations can be synthesized as two main takeaways.

First, regarding alliance signaling on Taiwan, successive South Korean administrations—both progressive and conservative—began to use and expand language on the importance of peace and stability in the Taiwan Strait less because of innate concerns about Taiwan or a commitment to act in the event of a cross-strait conflict and more to achieve intra-alliance and Korea-centric objectives. The Moon Jae-in administration’s adoption of new language regarding Taiwan was mostly driven by a desire to garner U.S. support to reenergize engagement with North Korea. The Yoon Suk Yeol administration expanded such language to strengthen Washington’s extended deterrence commitment to Seoul.

Second, respondents highlighted the fact that official alliance discussions on a Taiwan conflict were at a very nascent stage, if not nonexistent. When the subject of a Taiwan conflict is broached, South Korean officials—from the top down—immediately insist on turning the focus to North Korea and highlighting concerns about the use of United States Forces Korea (USFK) for Taiwan’s defense. Although the shifting alliance signaling on Taiwan has increased commentary, research, and analysis—including by South Korean experts—on how the alliance and South Korea should navigate a cross-strait conflict, it does not seem to have translated into official or detailed discussions within the alliance thus far. There remains deep-seated resistance.

Challenges to Discussing a Taiwan Conflict

Respondents highlighted a range of challenges and obstacles, which help explain the lack of substantive alliance discussions on a Taiwan conflict. These include:

• Washington’s mixed signals: Washington’s policy of strategic ambiguity toward Taiwan and mixed signals about whether it would come to Taipei’s defense undermine Seoul’s willingness to discuss the issue. Although arguing that this elides the main issue, some respondents acknowledged the need for U.S. officials and analysts to move beyond “are you with us or not”-style questions and initiate detailed discussions about the different types of contingencies and concrete expectations they have for Seoul and the alliance.
• Fitful evolution of hub-and-spokes alliance system: Despite new U.S. concepts of operations (CONOPS) that stress the distribution and interconnectivity of defense infrastructure in allies’ sovereign territory, there remains a lack of allied input. These CONOPS put new stresses on the longstanding hub-and-spokes alliance system, which has not properly evolved and requires adjustments. If there are expectations for allies in a Taiwan conflict, there must be a framework and plan in place—not necessarily a treaty but some sort of instrument that defines the concept—that includes allied involvement and buy-in.
• Faulty assumptions about other U.S. allies: Many respondents assumed other U.S. allies—Japan, Australia, and the Philippines—were more likely to be involved in a Taiwan conflict than South Korea. Such thinking could disincentivize South Korea from discussing a more active role and/or reduce expectations from U.S. policymakers about South Korea’s willingness to contribute. There is also a lingering misalignment between Washington and Seoul on the letter and spirit of the U.S.-ROK Mutual Defense Treaty. These assumptions and misalignment require greater scrutiny and interrogation, in which allied involvement and steady and considerate U.S. leadership are crucial.
• Complex and highly partisan views on China within South Korea: Despite growing negative sentiments toward China, South Koreans do not share the same threat perception or adversarial view of China—or anywhere near the same bipartisan consensus on competition with China—as Americans. Furthermore, contested views of China and a potential cross-strait conflict are inextricably linked with South Korea’s highly partisan domestic politics, which complicates the U.S.-ROK alliance’s ability to engage in detailed or formal discussions about such a conflict. However, partisan divides and perceptions thereof do more to muddle than clarify the picture.
• South Korean decision-making and bureaucratic dynamics: The top-down nature of South Korea’s foreign and national security process—with a presidential office that supervises and politically intervenes in the process—results in a weak buffer between the executive branch and the defense and military bureaucracy. The single five-year presidential term and notable policy shifts across administrations instill a fear of future demotions, can undermine the receptivity to top-level orders or policy lines, and limit how and to what extent relevant information moves upwards. Despite South Korea’s shift in diplomatic rhetoric on Taiwan, no further clarity has been provided on discussions or contingency planning for navigating a contingency. These bureaucratic dynamics disincentivize working-level officials and military officers from proactively exploring such planning in an alliance context.
• South Korea’s psychological dissonance: Respondents noted a psychological dissonance within South Korea—described as a lingering discrepancy between the country’s self-image of weakness and desire to keep focus siloed on the Korean Peninsula and its actual capabilities and broader responsibilities in the region—that obstruct discussions of a Taiwan conflict. While conceding the government had adopted a more robust rhetorical stance on Taiwan, respondents thought South Korea’s preference was to keep its “head in the sand” and proactively avoid the Taiwan issue.
• Uncertainty and ignorance within South Korea-Taiwan ties: Respondents highlighted a lack of security cooperation between South Korea and Taiwan, resulting in South Korean doubts about Taiwan’s preparedness and will to fight. Yet, South Korea was deeply reticent to move beyond low-level and unofficial engagement to address such doubts for fear of angering China. Also, rather than embrace being part of a holistic regional architecture or feel solidarity as partners who both face immediate adversaries in key geopolitical flashpoints, South Korea and Taiwan feel a degree of competition for the U.S. commitment. There remains persistent ignorance among the South Korean population and some political leaders about the deep economic linkages between South Korea and Taiwan (and the Taiwan Strait), with some even seeing advantages for South Korea in Taiwan’s misfortune.

Navigating a Taiwan Conflict

Respondents also provided insight on important variables or dynamics the alliance would have to navigate ahead of, during, and beyond a cross-strait conflict. Respondents broadly agreed that the variables could rapidly evolve depending on the level, pace, and geographic scope of escalation. Although this made for a complicated mix of interventions, it provides a holistic picture for analysts and policymakers to consider when weighing the complexity and gravity of the issues involved in a Taiwan conflict. While the subsections below do not follow a clearly linear conflict scenario, they interconnect in important ways, hopefully providing as cohesive a picture as possible.

• Applying the strategic flexibility of USFK to Taiwan: The strategic flexibility of USFK—the deployment of U.S. forces stationed on the Korean Peninsula to a regional contingency—is a longstanding topic of discussion and debate. Nonetheless, USFK’s force structure, posture, and mission make it ill-suited for direct military contributions to a Taiwan contingency. Were an appreciable number of USFK personnel and assets pulled from the peninsula into a Taiwan conflict, it likely means that the conflict has significantly escalated in intensity and geographic scope, U.S. forces have experienced heavy losses, and the United States and South Korea’s concerns have metastasized beyond the question of USFK’s strategic flexibility. Still, the alliance should hold in-depth discussions about the necessity for and possible levels of USFK’s involvement in a Taiwan conflict—depending on the course and speed of escalation—and how South Korea would fill capability gaps.
• Recalibrating USFK’s posture and structure: Historically, U.S. administrations have explored but not actualized ideas about transforming parts of USFK into mobile reserve units for flexible deployment to regional contingencies or into a more air- and naval-centric force posture. In the context of the new CONOPS, respondents considered restructuring USFK into a force that combined deterring North Korea with a more fluid regional role. However, such a change could spark U.S. inter-service rivalries and competition over billets on the peninsula depending on how the shift would change the existing four-star-led command structure. Also, it would undercut South Korea’s perception of the U.S. extended deterrence commitment, with the country possibly filling the perceived gap in fundamentally new ways. Finally, even if a reconceptualized USFK maintained sufficient capabilities for dealing with North Korea, it could spark serious concerns given its new multi-purpose regional role.
• Ensuring proper force allocation: A more immediate concern is that in the event a Taiwan conflict erupted first, U.S. forces normally slated for deployment to a Korean conflict would be diverted to the Taiwan Strait. This diversion would affect U.S. forces in Japan and the Japanese Self-Defense Forces (JSDF), both of which would play a critical role in the event of a Korean conflict. Such a diversion would significantly hamper the U.S. ability to deal with both theaters and could incentivize North Korea to opportunistically aggress, putting greater stress on South Korea and USFK to compensate for the lack of follow-on forces and undermining South Korea’s ability to contribute to cross-strait security.
• Altering the “arithmetic of deterrence”: Deterrence relies on capabilities and their credible, timely availability. A relative reduction in U.S. capabilities could weaken deterrence against North Korea, potentially encouraging opportunistic aggression, whether independently or in coordination with Beijing. If U.S. response options are limited due to Taiwan-related demands, officials may escalate deterrence measures more quickly, including nuclear signaling, to reassure Seoul. But North Korea might interpret these signals in different ways: as a credible threat requiring de-escalation, as justification for its own escalation, or as a bluff due to U.S. strategic overstretch. This situation would place a greater burden on South Korea, possibly leading to an unrestrained response if it perceives reduced U.S. support. Despite potential complications in the timely and cohesive functioning of alliance consultative mechanisms, the United States would likely try to restrain South Korea to avoid full-scale war, which could strain the alliance.
• Strengthening nuclear deterrence and reassurance: To address South Korea’s security concerns surrounding a Taiwan conflict, respondents proposed steps to enhance extended deterrence such as stronger nuclear signaling, deeper consultations on U.S. nuclear policy, redeploying U.S. tactical nuclear weapons to South Korea, establishing a nuclear-sharing arrangement, and revising the bilateral civilian nuclear cooperation agreement to allow South Korea to foster nuclear latency. Many noted that if the United States expects South Korea to shoulder greater responsibility on the peninsula, accept USFK’s strategic flexibility, and possibly engage in a Taiwan conflict, South Korea may need its own nuclear weapons.
• Constituting South Korea as a “retrograde and reconstitute” hub: Managing a Taiwan conflict in the Indo-Pacific’s contested logistics environment would be highly challenging. Respondents emphasized South Korea’s defense infrastructure and national capacities would be crucial in supporting U.S. and allied operations. Some saw South Korea as a “retrograde and reconstitute” hub, providing various kinds of rear-area support, depending on the scale of the conflict. Relevant South Korean capabilities include vast fuel storage, maintenance depots, deep ports, airfields, extensive transportation networks, and significant munitions production. However, some South Korean respondents stressed the need for the country to focus on civilian logistical support to avoid being perceived as a direct participant by China, which could trigger coercion or attacks. Given that Washington expects allied support in such a scenario, Seoul’s failure or unwillingness to offer its infrastructure and capabilities could raise concerns about alliance credibility.
• Aligning diplomatic signaling, connectivity, and sanctions: Diplomatic messaging will likely be critical, particularly in the early stages of a Taiwan conflict amid rampant mis- and disinformation. It will be important to form a coalition of countries willing to formulate individual and collective statements condemning Chinese aggression. South Korea was seen as a potentially critical country in galvanizing Global South involvement, given its diplomatic profile. Furthermore, respondents assumed China would attempt to significantly disrupt Taiwan’s digital connectivity through cyberattacks and by severing undersea cables. In such a scenario, South Korea could provide digital redundancies to help Taiwan maintain connections with the outside world. South Korea would also likely be expected to join multilateral sanctions against China in a Taiwan conflict.
• Enhancing South Korea’s role around and beyond the peninsula: If U.S. forces sustained casualties in a Taiwan conflict, South Korea would be an ideal place for medical evacuations. Additionally, the United States and South Korea would both be concerned about noncombatant evacuation operations of foreign nationals from Taiwan. Medical and noncombatant evacuation operations are critical yet non-military activities that fall under humanitarian support, which may be less likely to garner Chinese retaliation. More controversially, some respondents highlighted South Korea’s Jeju Naval Base—and an enhanced South Korean and allied maritime presence in the lower Yellow Sea/West Sea area—might serve an important role in deterring the People’s Liberation Army Navy’s (PLAN) Northern Theater Command Fleet either from aggression around the Korean Peninsula or deploying assets to the fight around Taiwan. The idea reinforced the growing sense that the line between defense of the Korean Peninsula and regional security was blurring. Respondents added that South Korea could also help uphold maritime security in the East China Sea by cooperating with other U.S. allies and partners to help escort and protect trading vessels around the Taiwan Strait. Such maritime operations could serve a range of non-military purposes, including humanitarian assistance, and would require multinational cooperation, all of which would provide strength in messaging and numbers and prevent South Korea from being overly exposed.

Big Picture Takeaways

Based on the dozens of interviews and open-source research, there are several takeaways that apply to the U.S.-ROK alliance and other regional allies and partners:

• Make-or-break role of allies: The United States would face multiple, complex challenges contesting a Chinese attack against Taiwan, even with the support and involvement of U.S. allies and partners. However, without allied support and involvement, the United States would very likely not succeed in deterring and defending against Chinese aggression, particularly if the conflict increased in scale and duration.
• Allied support not guaranteed: U.S. officials and analysts take things for granted or make grossly under-examined assumptions about what allies will or will not do, ranging from non-involvement to full mobilization. These assumptions require greater scrutiny and allied input during the clarification process, during which steady and considerate U.S. leadership is critical.
• Allied dissonance: U.S. allies like South Korea prefer the United States intervene on behalf of Taiwan in the event of a conflict because failing to do so would ultimately undermine their own core national interests. Yet, South Korean counterparts persistently maintain a deep reticence to discuss how they themselves would support or navigate such a conflict, with some hoping to avoid involvement altogether. The United States and its allies must reduce such dissonance if they are serious about the need to defend Taiwan.
• Beyond the U.S.-ROK alliance: The U.S.-ROK alliance cannot prepare for a Taiwan conflict on its own. It is not solely an alliance issue. The multiple dilemmas involved in a Taiwan conflict, its various interconnected spillover effects, and the need for multiple countries to work together to address the myriad risks involved, require multilateral cooperation and solutions.
• Taiwan’s inclusion: Deeper discussion about a Taiwan conflict must involve the Taiwanese people. As the people most vulnerable to a Chinese attack and blockade, the Taiwanese people and their leaders must be engaged directly—if prudently—to better understand their specific needs and expectations and the degree to which they would prefer others assist them in the event of such a conflict.
• Diplomacy must come first: Preparedness and messaging should be geared toward enhancing deterrence and reducing tension to prevent the outbreak of a conflict rather than further galvanizing the security dilemmas that make one more likely. Such a balance is immensely difficult to strike. It requires a multilateral approach to both maintain diplomatic pathways and cultivate risk-reduction and military-to-military communication with China.

 

Clint Work is a Fellow and Director of Academic Affairs at the Korea Economic Institute of America. The views expressed here are the author’s alone.

Feature image from Shutterstock.

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