Analysis: South Korea, Japan, U.S. trilateral cooperation still faces obstacles
Discontinuity in U.S. attention to the region will substantially impact the trilateral partnership.
Event or Trend: Senior Officials from the United States, South Korea and Japan will meet for trilateral talks to discuss how to boost the partnership. Despite recent efforts to solidify trilateral cooperation between South Korea, Japan, and the United States, significant risks threaten the sustainability of this relationship.
Significance: The trilateral partnership between South Korea, Japan, and the United States has drawn significant attention due to the attention accorded to it by Washington to address security concerns regarding China. In recent months, high-level summits and renewed agreements have aimed to formalize cooperation, in order to institutionalize military, economic, and diplomatic ties. These efforts, while essential to regional stability, still face considerable obstacles.
Historical animosities between South Korea and Japan remain a source of contention and divergent domestic political priorities and unpredictable U.S. foreign policy shifts threaten the long-term sustainability of the trilateral relationship. For policymakers and analysts, understanding these risks is critical for ensuring the durability of the cooperation. Despite the strong publicity promoting trilateral cooperation, the partnership will struggle to evolve beyond short-term alignment.
Analysis: Recent diplomatic engagements between South Korea, Japan, and the United States have been hailed as significant steps toward institutionalizing trilateral cooperation, particularly in the context of growing U.S. security concerns in East Asia. The August 2023 Camp David summit, which resulted in agreements to expand military coordination and intelligence sharing, underscores the strategic value the U.S. places on securing allied support to counter China's assertive regional posture.
Seoul is currently pushing to secure the hosting of a Trilateral Secretariat, arguing that the influence of the partnership on future (perhaps less supportive) administrations would be strengthened by the responsibility and commitment that it entails. Since 2011, Seoul has hosted the China, Korea, Japan Trilateral Cooperation Secretariat (TCS), meaning that if agreed, it would be host to two trilateral secretariats. Reflecting the Yoon Administration’s neglect of the TCS, location does not necessarily support policy action. A future South Korean presidential administration less supportive of United States, South Korea and Japan cooperation will still present a major challenge.
The trilateral relationship remains fragile, with several factors posing risks to its long-term sustainability.
Historical tensions. The South Korea - Japan relationship places strain on the relationship. Deep-rooted grievances regarding Japan's colonization of Korea, the issue of forced labor and sexual slavery during World War II, and territorial disputes resurface periodically, and undermine diplomatic progress. There has been no long-term resolution to these issues. While South Korean President Yoon Suk-yeol has sought to improve relations with Japan, these efforts have been met with mixed reactions domestically. The South Korean public remains deeply divided, and any perceived concession to Japan risks domestic political backlash.
Similarly, Japanese leaders have faced nationalist pressures, limiting their ability to fully address these historical issues in a way that satisfies South Korea. These tensions create a volatile undercurrent that could derail the trilateral partnership, especially if nationalist sentiments are exploited by political actors during elections or moments of heightened tension.
Domestic politics. The political landscape in South Korea and Japan introduce significant uncertainty into the trilateral equation. Both countries have upcoming political decision points, which could shift the priorities of their respective governments.
Presidential elections in South Korea will be held in March 2027. A change in leadership is likely to result in a pivot away from current rapprochement efforts with Japan. Japanese Parliamentary elections are due 27 October 2024. While a change in leadership is highly unlikely, a rebalancing of forces that produces political instability or factional change could slow or reverse the current momentum toward reconciliation.
Domestic political cycles in both countries poses a significant risk to the continuity of trilateral cooperation, as newly elected leaders may prioritize internal issues over external alliances.
U.S. presidential elections. Foreign policy unpredictability remains a critical factor with the possibility of President Trump returning to the White House. While the Biden administration has prioritized rebuilding alliances in the Indo-Pacific region, the upcoming U.S. presidential election in 2024 could result in a shift in focus or a reduction in commitment to maintaining a robust trilateral framework. Former President Donald Trump’s approach to alliances, which was transactional and at times dismissive of long-standing partnerships, serves as a reminder that U.S. engagement in the region cannot be taken for granted.
A return to such policies under a future administration could lead to a weakening of the trilateral arrangement, particularly if the U.S. seeks to reduce its security commitments in the region or emphasizes bilateral over multilateral approaches.
Regional dynamics, especially concerning China and North Korea, further complicate the sustainability of the trilateral relationship. While the three countries share common security concerns, their approaches to managing relations with China differ. South Korea holds a more cautious approach to balancing its security ties with the U.S. and its economic reliance on China; Japan takes a more assertive stance on Chinese territorial claims, but ensures a strong economic working relationship with China.
The U.S. stance on China differs due to its size and geographic distance. These differing approaches could lead to frictions within the trilateral framework, particularly if China intensifies its efforts to drive a wedge between these allies through economic pressure or diplomatic overtures. Both South Korea and Japan fear the potential of the U.S. to negotiate a “grand bargain” with China.
North Korea's unpredictable behavior also adds another layer of risk. While Pyongyang's missile tests and nuclear threats have largely driven the recent convergence of South Korea, Japan, and the U.S., a sudden shift in North Korean strategy—such as renewed diplomacy or a pause in provocations and movement towards reconciliation—could lessen the urgency for trilateral cooperation (particularly under a progressive South Korean administration). This could lead to complacency or a reduction in the intensity of collaboration, especially if domestic political priorities shift toward other pressing issues.
Outlook: In the short term (0-12 months), the trilateral relationship will likely continue to show signs of progress, driven by the promotion of external security threats and recent diplomatic gains. However, in the medium term (1-5 years), domestic political changes in South Korea and Japan, coupled with potential shifts in U.S. foreign policy after the 2024 election, could introduce significant challenges.
Over the long term (5-10 years), the institutionalization of this relationship will depend on resolving historical grievances, managing domestic political transitions, and navigating regional dynamics involving China and North Korea. Discontinuity in U.S. attention to the region will substantially impact the trilateral partnership.