ABSTRACT
The Treaty ofMutual Cooperation and Security between Japan and the United States1 celebrated its fiftieth anniversary in 2010. Despite dramatic changes in the international system and the relative distribution of power between the two countries since its inception, the security treaty remains the centerpiece of U.S. and Japanese strategy in Asia and a lynchpin of regional stability. The core strategic bargain struck between the United States and Japan a half century ago continues to guide the security relationship to the present day: a U.S. commitment to defend Japan in exchange for U.S. access to bases in Japan for the maintenance of peace and security in the Far East. The original 1960 Treaty also included clauses to strengthen bilateral economic cooperation and support international institutions such as the United Nations, two key elements now that the United States and Japan are the first and third largest economies in the world and the two largest contributors to the UN system. Over the past two decades, American and Japanese leaders have also begun framing the U.S.-Japan alliance in a global context as the two nations have confronted new challenges across a range of issue areas from nuclear proliferation and the scourge of terrorism to humanitarian relief and multilateral trade liberalization.
