Changes in the power relationships in the Asia-Pacific quadrilateral—made up of Japan, the People's Republic of China, the United States, and the Soviet Union—also called for reexamination of policies.
Sino-Soviet split and confrontation, the dramatic rapprochement between the United States and China, the rapid reduction of the United States military presence in Asia following the Vietnam War all required a reevaluation of Japan's security position and overall role in Asia.