美日安保條約
In 1951, the Treaty of San Francisco was signed by the allied countries and Japan, which restored its formal sovereignty. At the same time, the U.S. and Japan signed the Japan-America Security Alliance. By this treaty, USFJ is responsible for the defense of Japan. As part of this agreement, the Japanese government requested that the U.S. military bases remain in Japan, and agreed to provide funds and various interests specified in the Status of Forces Agreement. At the expiration of the treaty, the United States and Japan signed the new Treaty of Mutual Cooperation and Security between the United States and Japan. The status of the United States Forces Japan was defined in the U.S.–Japan Status of Forces Agreement. This treaty is still in effect, and it forms the basis of Japan's foreign policy.