Quasi alliance explanation for the fluctuating ROK-Japan relationship: analysing friction in 2019 and cohesion in 2023

Abstract

ABSTRACT The ROK-Japan relationship, characterized as a quasi alliance, has oscillated between moments of friction and cohesion. This study endeavours to pinpoint the explanatory variables responsible for these fluctuations and to articulate a coherent causal mechanism. Drawing upon alliance theories and the quasi alliance model, two hypotheses centred on external factors – common threats and common allies – are posite. In 2019, divergent threat perceptions between the ROK and Japan, coupled with doubts about the US's reliability, strained their quasi alliance. Yet, as the prospects for North Korea's denuclearization grew murky, both the ROK and Japan began to share heightened threat perceptions. Concurrently, the US's commitment and credibility were reestablished, bolstering the cohesion of the quasi-alliance. This study strengthens the quasi-alliance model both theoretically and empirically. Furthermore, the study's findings suggest the necessity for more direct and binding bilateral ties between the ROK and Japan to ensure greater stability in future relations.