With a mini-Cold War emerging in East Asia and the Japan-U.S. alliance appearing less robust in the initial phase of the inexperienced new Trump administration, Tokyo needs to take some additional measures to safeguard its security.
To maintain the regional status quo, Japan depends on the overwhelming U.S. military power that can be brought into play through the alliance. Japan can only play limited supplementary and complementary military roles vis-a-vis the United States. This means Japan must follow the U.S. lead in North Korea policy, which involves highly strategic issues such as nuclear deterrence and missile defense, while closely coordinating its defense policy with Washington. Yet, on the other hand, Japan has opportunities to buttress U.S. security policy toward Chinese expansionism in the South and East China seas.
A full-scale conventional U.S.-China war is unlikely given superior U.S. air and naval power in the two seas. China is fully aware of the disparity, particularly when U.S. and Japanese military power is combined.