Trilateralism Rejected
South Korea has opted out of a U.S.-led trilateral air exercise with Japan that included B-52 strategic bombers. This decision has sparked new worries in Washington regarding its longstanding alliance with Seoul, especially as the Trump administration steps up its deterrence efforts against China.
According to South Korea’s Chosun Ilbo, the U.S. and Japan proceeded with air drills on February 16 and 18 without South Korea’s participation. The exercises featured four B-52H bombers, regarded as some of America’s prime long-range strike capabilities.
This situation escalated beyond mere training. The B-52s flew through airspace from south of Jeju Island to Taiwan before moving northward and briefly entering the West Sea. Simultaneously, U.S. Forces Korea conducted significant F-16 drills in the same maritime area.
In response, Chinese forces scrambled their jets, leading to a standoff in international airspace with U.S. aircraft. Rather than supporting its ally, Seoul reportedly expressed dissent to Washington following the confrontation between U.S. and Chinese jets, which could be problematic for U.S. strategies aimed at countering Beijing’s increasing assertiveness.
Testing the Status Quo: First Island Chain Defense
The timing of this incident is noteworthy. The National Security Strategy of the Trump administration, released in December, underscored the need to bolster deterrence “by denial” along the so-called First Island Chain. This area encompasses allied territories from Japan to Taiwan and the Philippines, forming a crucial barrier against Chinese military expansion into the Pacific.
By deploying B-52s alongside Japanese air forces in this corridor, the U.S. is sending a clear message: it intends to contest Chinese coercion and prevent unilateral alterations to the status quo in Northeast Asia.
Japan’s Joint Staff emphasized that the exercises reinforced allies’ commitment to preventing “unilateral changes to the status quo by force,” language often used by Washington and Tokyo to criticize Beijing’s territorial ambitions.
However, South Korea’s choice to sit this one out highlights a growing strategic divergence. President Lee Jae Myung has put forth the idea of “strategic autonomy” in foreign policy, warning against becoming too entangled or too detached from alliances.
His administration is also contemplating a reduction in certain joint exercises with the U.S. to ease tensions with North Korea. Yet, the ongoing global geopolitical landscape means that the Korean Peninsula is no longer isolated from broader Indo-Pacific dynamics. China’s military advances, its collaboration with Russia, and its expanding naval presence are all factors impacting U.S. forces in Korea.
This is part of why Washington is reassessing the role of U.S. Forces Korea (USFK), contemplating a shift from a North Korea-centric focus to a broader regional deterrence strategy against China.
South Korean Strategy: Intention or Drift?
The recent consolidation of F-16 squadrons into a “super squadron” and expanded operations in the West Sea signal this evolution. The Pentagon views the Korean Peninsula not just as a North Korean issue but as a vital component in the Indo-Pacific deterrence framework.
South Korea’s reluctance to participate in trilateral drills may send a different signal. If it abstains from exercises aimed at protecting navigation rights and deterring Chinese pressure, Beijing might interpret this as a weakness in the alliance.
Though alliance unity serves as a deterrence in itself, there’s a palpable divergence within South Korea. Critics argue that getting involved in the U.S.-China rivalry could heighten tensions in the region. However, shying away from visible cooperation carries risks. Great Power competition doesn’t simply pause because an ally leans toward strategic ambiguity.
Moreover, there are reports that the reduction of live-fire training and mobility operations under the annual “Freedom Shield” drills is under consideration. This change could have ripple effects, potentially compromising readiness against North Korea while also affecting responses to broader contingencies requiring quick integration of U.S. and allied forces.
The inter-Korean military agreement from September 19, 2018, was initially intended as a confidence-building measure for both nations. However, unilaterally reinstating these constraints without corresponding concessions from North Korea might restrict surveillance and response capabilities, especially as Pyongyang continues its missile programs and strengthens its ties with Moscow and Beijing.
The China Factor
For U.S. strategists, a key concern lies in how China interprets these developments. China’s Global Times reported that the People’s Liberation Army (PLA) conducted surveillance in response to U.S. aerial activities near its air defense identification zone. Beijing constantly frames U.S. military operations as destabilizing, even as it expands its military footprint in the region.
Effective deterrence relies on credible presence and, in turn, credibility demands visible coordinated efforts among allies. When American bombers fly without South Korean involvement, followed by public diplomatic disputes, adversaries take note.
Washington might not expect its allies to completely echo its sentiments. However, there’s a need for the alliance to convey a sense of stability. A perception that Seoul is distancing itself from regional deterrence efforts could complicate U.S. operational strategies and encourage Chinese probing.
Deciding the Future
This situation doesn’t imply that the U.S.-South Korea alliance is on the verge of collapse. The foundational treaty remains solid, and military cooperation continues. Yet, the incident reveals a rising tension between Washington’s Indo-Pacific strategy and Seoul’s wish for more maneuverability between powerful nations.
The underlying question is whether South Korea can maintain its “strategic autonomy” while also adhering to a deterrence policy aimed at curbing China. If Seoul continues to resist engaging in exercises relevant to wider Indo-Pacific security and openly challenges U.S. deployments that provoke Chinese reactions, there will likely be ramifications.
American policymakers may increasingly question Seoul’s commitment to supporting a rules-based order in the region. Ambiguity might attract unwanted pressure, especially in this era characterized by fierce Great Power competition.
Ultimately, the First Island Chain represents more than just a geographical boundary. It serves as a litmus test for the resolve of alliances, and the decisions made in Seoul will influence how both Washington and Beijing view their power dynamics in East Asia for years to come.
