U.S.-South Korea Coordination Toward China: Maritime Security

Introduction

For many South Korean observers, Taiwan is one of four hotspots for a potential conflict between the United States and China in East Asia. The other areas of concern include the Senkaku/Diaoyu Islands, the Korean Peninsula, and the South China Sea. As such, the Taiwan Strait represents a nexus of international relations, where the interests of major powers converge and contend under the shadow of an uncertain future. China’s maritime ambitions entail reshaping the landscape, especially in the contentious waters of the Taiwan Strait and the South China Sea. In a bold statement of sovereignty in 2010, China began to call Taiwan a “core interest,” signaling its readiness to use military force to defend this claim. The proclamation of China as a “maritime great power” in 2012 and the launch of its first aircraft carrier, the Liaoning, the same year underscore China’s ascent as a formidable naval presence.

The Taiwan Strait and the South China Sea are critical maritime pathways for global trade, with some of the busiest shipping lanes in the world facilitating the movement of a significant portion of global maritime trade. South Korea, as a major trading state, relies heavily on shipping routes for its exports and imports. More than 90 percent of Korea’s maritime trade volume passes through the Taiwan Strait and the South China Sea. Anchored by this fact, Seoul has a vested interest in the preservation of unimpeded maritime routes. This economic lifeline—coupled with the need to balance its strategic relationships between the United States, its traditional ally, and China, a key trading partner—has fostered a cautious diplomatic stance.

The Taiwan Strait, a mere 130 kilometers (roughly 81 miles) of turbulent waters separating Taiwan from mainland China, has emerged as one of the world’s most precarious potential flashpoints, with Beijing’s intensifying assertiveness toward Taipei stoking fears of a cross-strait military confrontation. This geopolitical chokepoint—a hub of vast economic significance and a pivotal link in the global supply chain, especially semiconductors—has become the stage for a complex power play that resonates far beyond its immediate geography. China’s ramped-up aerial incursions and naval maneuvers, not to mention Chinese leader Xi Jinping’s periodic reminders that China “will never promise to renounce the use of force,” signal not just a bristling impatience with the status quo but also serve as a barometer of China’s growing military confidence and willingness to project power. Any miscalculation could escalate into open conflict, threatening regional stability, economic networks, and alliances.

This rapid militarization of the South China Sea has further entangled the intricate web of regional maritime security. This trend has significant ramifications for the United States and South Korea, necessitating a recalibration of their collective defense strategy to counterbalance China’s growing influence and assertive maneuvers in this pivotal maritime domain. Against this backdrop, South Korean President Yoon Suk Yeol has offered a robust endorsement of the Camp David joint declaration, a document that pointedly names China in its censure of what it describes as “dangerous and aggressive behavior” in the South China Sea. Furthermore, the declaration underscores South Korea’s position on Taiwan, aligning with the tone of firmness and diplomatic solidarity expressed in the text.

Summary of the CFR Workshop

The Council on Foreign Relations held an in-person workshop on November 1, 2023, on “U.S.-South Korea Policy Coordination Toward China on Maritime Security.” The workshop’s core takeaways included the following:

• Despite the stated urgency of the matter, and even as the Taiwan issue has become a significant policy priority for the Joe Biden administration, it has not been fully integrated into South Korea’s normative security considerations, indicating Seoul’s cautious stance amid volatile regional dynamics. South Korea’s approach to tensions across the Taiwan Strait is contingent on several pivotal factors. At its core lies Seoul’s confidence in its deterrent capabilities against Pyongyang, particularly given North Korea’s de facto status as a nuclear state. South Korea will be reluctant to be pulled into a Taiwan crisis when doing so risks its security vis-à-vis North Korea. Seoul’s fear is real, as Pyongyang invaded the South in 1950.

• The calculus of a crisis involving Taiwan invariably brings China into consideration. China’s status as South Korea’s key trading partner—combined with its geographical and geopolitical proximity, including China’s leverage over North Korea—casts a long shadow over Seoul’s potential role in any Taiwan contingency. Since the Korean War, South Korea has not faced direct military conflict with China, positioning any involvement in a Taiwan crisis as an unprecedented venture fraught with considerable risks to national security. As such, thoughtful deliberation, strategic communication, and meticulous preparations are deemed indispensable for South Korea as it navigates this geopolitical tightrope, balancing its security interests with regional stability.

• The tenor of South Korea’s bilateral ties with the United States is crucial, as is South Korea’s assessment of how a potential conflict over Taiwan could ripple through to its own security. South Korea’s potential involvement in a Taiwan contingency would likely hinge on the degree of the United States’ own attention toward the situation and the strength of the Washington-Seoul alliance. This situation mirrors the dynamics that were at play when Russia invaded Ukraine, during which the level of engagement by U.S. allies was primarily steered by Washington’s leadership and its orchestration of allied actions, rather than direct bilateral interactions with Ukraine.
• As a vibrant democracy, the South Korean government’s decisions will be significantly influenced by domestic public sentiment. Winning the hearts and minds of the South Korean people is crucial. This includes fostering closer people-to-people ties, not just between South Korea and the United States, but also raising Taiwan’s profile in South Korea through cultural exchanges, tourism, and civil advocacy via seminars and forums. Without such engagement, Taiwan remains a distant concern for many South Koreans, raising questions about the wisdom of potential military involvement.
• Washington could facilitate improvements by subtly encouraging interaction, leveraging its convening power, and inviting Seoul and Taipei to the same gatherings. It is a common misconception that countries in the same region, both reliant on the United States for security, will naturally bond and strengthen ties. The relationship between South Korea and Japan proves otherwise, a point that has often frustrated U.S. policymakers. Diplomatic relations do not spontaneously improve; they require effort and careful navigation. For instance, the semiconductor industry is an area in which South Korea and Taiwan are fierce competitors.
• As South Korea positions itself as a “global pivotal power,” it needs to embody this role. It can no longer justify its limited engagement with Taiwan by citing preoccupations with North Korea, fears of Chinese retaliation, or domestic political schedule, such as the upcoming legislative elections in April this year. Other countries, facing their own political challenges, still find ways to connect with Taiwan. South Korea should aspire to do the same.

Maritime Security Within the U.S.-South Korea Alliance

South Korea, ensconced in the regional dynamics of East Asia, will inevitably calibrate its policies mindful of its colossal neighbor, China, whose retaliatory economic measures can strike like a whip, swift and stinging, against perceived slights. The specter of open conflict with China casts a long shadow over the peninsula, raising the stakes for the Washington-Seoul alliance. Such a conflict, once an abstract dread, has assumed a chilling reality in strategic calculations, necessitating a level of military preparedness that should be weighed against the imperatives of de-escalation and diplomacy. The alliance is as robust as ever, but it also stands at a crossroad with new challenges. Each step forward needs to be measured not just in the immediacy of shared defense objectives, but in the broader context of a changing global order and the pursuit of enduring stability in East Asia and the Indo-Pacific region. The most significant challenges to the U.S.-South Korea relationship with regards to maritime security include the following:

• South Korea’s heavy economic reliance on China as a trade partner is juxtaposed against its security reliance on the United States. This creates a dichotomy in policymaking, often forcing Seoul to balance between the strategic imperatives of the alliance and economic pragmatism, even under decidedly pro-American President Yoon.
• The United States views the South China Sea through the lens of global power dynamics and rule of law, while South Korea’s perspective is more regional and focuses on its immediate security environment and the Korean Peninsula.
• China’s investment in asymmetric warfare tactics, such as anti-access and area-denial capabilities, poses a significant challenge for U.S.-South Korea maritime operations, requiring innovative countermeasures.
• As China continues to advance its technological capabilities, there is a growing challenge in monitoring and countering its developments in areas like cyber warfare and artificial intelligence, which can significantly impact maritime security. Pertinently, China established the Strategic Support Force in 2015 as part of Xi’s efforts to modernize the country’s armed forces to leverage advanced technologies and civilian-military integration for modern warfare.

While those challenges are significant, U.S. and South Korean policymakers have several opportunities to reinforce their shared strategic capabilities and build a regional security apparatus that can discourage conflict and encourage maritime security. They include the following:

• The United States and South Korea could leverage their technological industries to codevelop maritime surveillance and defense technologies, enhancing their strategic edge in the region.
• The two countries could significantly bolster their maritime cooperation to counter China’s expanding maritime strategy and assertiveness. This collaboration could include initiatives such as joint search-and-rescue operations, coordinated port calls, and the mutual support of freedom of navigation operations along critical sea routes.
• The current moment provides an opportunity to broaden the existing network of alliances by including other regional players that share concerns over maritime security, thus dispersing the pressure among a larger coalition. The U.S.-South Korea alliance can work through regional multilateral forums like the Association for Southeast Asian Nations (ASEAN) and the East Asia Summit to build a consensus and promote a rules-based order.

Recommendations

To reduce the risk of conflict breaking out in the South China Sea or Taiwan Strait, and to ensure the lasting strength of the U.S.-South Korea alliance and the current state of maritime security, workshop participants suggested that policymakers in Washington and Seoul pursue the following steps:

• Develop a joint strategic framework for maritime security. The United States and South Korea should craft a joint strategic framework that addresses maritime security concerns in the South China Sea and the Taiwan Strait, aligning their operational and tactical initiatives.
• Enhance trilateral cooperation with Japan to shore up regional deterrence capabilities. The United States and South Korea should engage with Japan to form a trilateral strategic dialogue focused on maritime security in the Taiwan Strait. This initiative should be both aspirational and realistic, which will require it to take public sentiment in South Korea into greater consideration.
• Strengthen engagement with ASEAN to bolster maritime norms. Closer ties with ASEAN countries would allow South Korea and the United States to build capacity and resilience against coercive actions in the South China Sea, thus promoting a rules-based maritime order.
• Reaffirm commitments to international law. The U.S.-South Korea alliance should consistently reaffirm the importance of adhering to international law, specifically the UN Convention on the Law of the Sea.
• Establish new crisis-management mechanisms. Jointly managed crisis-management protocols should be developed to prevent and de-escalate maritime incidents that could lead to conflict, ensuring coordinated responses between U.S. and South Korean forces.
• Deepen economic cooperation with Southeast Asia. Stronger economic ties with Southeast Asian countries could help reduce overall economic reliance on China, potentially through free trade agreements or economic partnerships, which would enhance regional economic stability and create strategic economic leverage.
• Ensure consistent U.S. policy on China. As a middle power situated geographically close to China, South Korea places a high value on the steadfastness of U.S. policy toward China. Washington’s efforts to renew engagement with Beijing could produce unintentional results by planting doubts in the minds of U.S. allies in East Asia, where China is already gaining an advantage on the economic front. There is a growing voice in South Korea advocating for a hedging strategy, as many are wary of being entrapped in an inconsistent approach toward China.
• Clarify U.S. policy on China for the South Korean domestic audience. Some South Koreans view U.S. engagement with China as self-serving, even as Washington calls for unity among its allies to counter Beijing. The United States needs to deepen coordination and alignment with its allies to ensure that such perceptions are not exploited by Beijing.

Conclusion

The U.S.-South Korea alliance is at a critical juncture as China’s maritime assertiveness intensifies. Coordination between Washington and Seoul is imperative to uphold the rules-based international order, particularly in the maritime domain. While there are inherent challenges in aligning the strategic priorities of both countries due to South Korea’s significant economic ties with China, the alliance also has unique opportunities to enhance regional security through increased cooperation and a reaffirmation of commitment to international norms. Given the volatile nature of disputes in the South China Sea and tensions in the Taiwan Strait, a failure to effectively coordinate could undermine the credibility and deterrence capabilities of the U.S.-South Korea alliance, potentially destabilizing the regional security architecture. Conversely, a well-synergized approach could serve as a cornerstone for peace and stability in the Indo-Pacific, demonstrating the enduring strength and adaptability of the U.S.-South Korea partnership in the face of evolving security dynamics.