The US–Japan alliance and the role of the US Marines on Okinawa in extended deterrence

The relocation of the controversial Marine base at Futenma on Okinawa to Henoko in the north of the same island has been framed by Japanese politicians, officials, and analysts as crucial to deterrence. Critics respond that deterrence is merely a pretext, and the relocation is a politically convenient solution that perpetuates discrimination against Okinawa by the central government in Tokyo. This article draws on deterrence theory to evaluate the deterrence claims made by relocation proponents. It finds little evidence to support them: the Marines’ capabilities pale against the massive US forward deployment, including the Seventh Fleet and the Fifth Air Force. As for the local balance of forces, the Marines are unlikely to participate immediately in a local conflict, and their geographical location leaves them vulnerable; current US strategy is to down-scale and disperse Marine units. If one were focusing on defence rather than political convenience, the Marines would be relocated off Okinawa. In terms of credibility, the article finds that other US bases in Japan play a much more important ‘tripwire’ role, and ultimately, given inter alia the security treaty, joint exercises, and deep interoperability, US extended deterrence to Japan is as credible as possible under the circumstances.