Why Japan cancelled the deployment of the Aegis Shore missile defence system

Abstract

Despite the worsening security situation in East Asia, in 2020, Japan suddenly and abruptly canceled the deployment of the Aegis Ashore missile defense system. Why is that? I argue that neither the often-cited neorealist theory nor the official government explanation well define the reasons that lead to the cancellation. Instead, I build on the neoclassical realist paradigm and illustrate three key components that led to this abrupt political change: ShinzoAbe's leadership, changes in domestic political decision-making process, and the role of external actors (US and China). The research found out that personal and politico-cultural factors play essential roles in Japanese decision-making in addition to systemic pressures. The relationship with China also had played a vital role in making security policy. The combination of individual, domestic and systemic factors provide a holistic picture of how and why such a decision has transpired. Keywords Japan, Ballistic Missile Defense (BMD), Aegis Ashore, neo-realism, Neoclassical realism Range of Thesis: 55 Pages, 13 476 words, 87 798 characters