Minilateralism and Trilateral Cooperation in Northeast Asia: Implications for Regional Security and Order-Building

This article examines the evolving dynamics of minilateralism and trilateral cooperation in Northeast Asia, and assesses their implications for regional security and order-building. It traces the development of minilateral frameworks in the region since the end of the Cold War, focusing in particular on two key trilateral cases: security cooperation between the United States, Japan, and South Korea, and functional cooperation between China, Japan, and South Korea through the Trilateral Cooperation Secretariat (TCS). It is argued that US–Japan–South Korea trilateralism, which was initially shaped by the need to address the North Korean nuclear challenge, has become a core element of the US-led security architecture aimed at balancing China’s growing influence in the Indo–Pacific. By contrast, the TCS reflects a pragmatic form of minilateralism centred on economic and technical cooperation. Yet its effectiveness has been constrained by deep-seated geopolitical tensions and institutional limitations, particularly amid intensifying US–China rivalry. The article concludes that while trilateral minilateralism offers new avenues for coordination, it also risks exacerbating security dilemmas. Strengthening institutional mechanisms for strategic communication, confidence-building, and risk reduction will be essential to supporting regional stability and order-building.