(A) There were important changes in the policies of various major powers toward the Southeast Asian countries partly because of the trend toward multipolarization of international relations; the international environment in Southeast Asia also changed greatly. Since the inauguration of President Nixon in 1969, the United States has carried out its new Asia policies based on the so-called Nixon Doctrine and has achieved epochal results in improving its relations with China, including the realization of President Nixon's visit to China. After the Cultural Revolution had come to an end and its diplomatic function had been restored in the spring of 1970, the People's Republic of China showed moves to form an anti-American united front with the other communist countries in Asia. However, it has intensified interchange with Southeast Asian countries since the spring of 1971, and its international position has risen remarkably for such reasons as the realization of its participation in the United Nations. In connection with the Soviet Union's Asian collective security plan being proposed since 1969, Soviet Premier Kosygin and General Secretary Brezhnev spelled out in their speeches in March 1972 four principles, namely, (1) non-use of arms, (2) respect for sovereignty and inviolability of frontier, (3) non-intervention in the domestic affairs of other countries and (4) development of cooperative relations on the basis of equality and reciprocity, and disclosed concretely the contents of the plan for the first time. The Soviet Union continues to promote political, economic and cultural interchange with various Southeast Asian countries.