Japan was effectively disarmed after its defeat in 1945, but America remembered from the disaster that was the Treaty of Versailles that punitive occupations would be counterproductive. The country would be swiftly rebuilt with the help of the U.S. and their beloved Emperor Hirohito absolved from any war crimes charges. In this way the United States and Japan were able to quickly normalize relations. The U.S. would need Japan as a base of operations to operate in the Far East.

On this day, March 20, in 1952, Japan and the United States signed a treaty granting American soldiers exclusive permission to launch operations from Japanese soil. In return the United States recognized Japan’s sovereignty and promised to defend it from all armed attacks.

The defense agreement was expanded into a more broad-based mutual cooperation treaty in 1960. That agreement cause some controversy in Japan in the 1990s, as American Marines stationed on the Okinawa island were convicted of several crimes against the native population, but recent polls have found an overwhelming majority still supporting the treaty.