Collective self-defense and US-Japan security cooperation

Abstract

If Japan decides to exercise its right of collective self-defense (CSD), it would have complex effects on US-Japan security cooperation. The tangible short-term outcomes would likely be rather modest, and mid-term outcomes are dependent on changes in complementary policies, laws, and attitudes. American observers who expect that a revised interpretation of Japan's Constitution will provide an immediate boost to the alliance are likely to be disappointed. There are institutional and legal limitations on the Japanese Self-Defense Forces (SDF) that will constrain its activities in the near-term, no matter what policy course leaders choose. Japanese public opinion is also highly circumspect about the use of force to resolve international problems and will likely not support missions that do not directly address the security of Japan. However, due to the powerful symbolism of CSD, the long-term effects could be quite significant. The removal of restrictions on CSD would enable the SDF to carry out a limited number of new operations and operate differently in several other scenarios. Although the constitutional prohibition on engaging in front-line combat would remain, Japanese forces could defend US ships in international waters and intercept ballistic missiles targeted at US forces. The SDF may also face fewer restrictions on peacekeeping operations. Japanese logistical support for international security operations, whether or not under a United Nations framework, could be rationalized on a policy basis, no longer handicapped by legal constraints. As a result of these changes, the US-Japan alliance could develop more flexible regional contingency responses and rethink force structure, interoperability, and command and control mechanisms. At the regional level, Japan would open doors to fuller security partnerships with Asian states, for example through military exercises. More multilateral defense cooperation could improve regional stability, though conversely it may exacerbate concerns about a latent "anti-China" coalition. Strategic communications will be important in shaping how countries in the region and around the world perceive a change in Japanese security policy. The degree to which Tokyo can construct the narrative of CSD around contributing to regional and international security, rather than accusations of nationalism and resurgent militarism, will partly determine the success of this potential policy shift.