What Makes Good Trilateralism? Theorizing the Utilities of Trilateralism in East Asia

In recent decades, the development of trilateral institutions has proliferated widely in East Asia. Inspired by an analysis of minilateralism, prevailing studies have spoken highly of trilateralism, as trilateral groupings offer greater outputs for regional community building. In contrast to the prevailing optimism, this study argues that trilateralism – the miniature form of multilateralism – is not unconditionally “good.” A three-party arrangement is seen as potentially problematic, and its effectiveness is not guaranteed. This research examines two potential structural uncertainties for trilateralism in East Asia, which are the efficiency problem and the solidarity problem. This article sets up a theoretical model for examining the utility and operability of trilateralism in East Asia, and presents a cost–benefit analysis by comparing the utility of trilateralism with those of bilateralism and multilateralism. In East Asia, countries have been struggling with bilateral conflicts, and the prevailing logic of rivalry has led to the pursuits of “relative gains.” Thus, three preconditions are required in order to establish a “good” trilateralism: firm shared interests that prevent trilateral agreements to be eclipsed by embedded bilateral approaches, stable bilateral ties that ensure the operability of trilateral arrangements, and an effective leading country for implementing coherent policy responses. This article also enacts theories into practices and explains the performances of three trilateral relations (US–Japan–Australia, US–Japan–Korea, and China–Japan–Korea) in East Asia.