Treaty of Mutual Cooperation and Security between the United States and Japan

The Treaty of Mutual Cooperation and Security between the United States and Japan, better known as the U.S.-Japan Security Treaty or in Japanese as the Anpo treaty, permits United States military bases on Japanese soil and commits each nation to defend the other if it is attacked in territories under Japanese administration. The current treaty took effect on 23 June 1960 and revised and replaced an earlier version signed in 1951 alongside the Treaty of San Francisco. The 1960 revision was highly contentious in Japan and provoked the Anpo protests, the largest popular protests in that nation's history. It added mutual defense obligations, required advance notice to Japan before American forces mobilized, and dropped the clause allowing American interference in Japanese domestic affairs. It has never been amended since 1960 and continues in force indefinitely unless a party gives one year's notice.