Anxious to establish their place among the nations of the world, the Philippines joined the United Nations when the organization was established in 1945. In 1947 they signed a treaty of friendship with France, and from 1951 onwards they strengthened their relations with neighbouring countries by treaties of friendship and summit conferences. The most significant agreement, reflecting a common consciousness of belonging to South-East Asia, was the Treaty of Manila in 1954 which established SEATO (the South-East Asia Treaty Organization). The treaty, designed to combat the rising tide of communism in Asia, provided for mutual defence against any aggression in South-East Asia. The signatories were the Philippines, Thailand, Pakistan, the United States, New Zealand, Australia and France; but the three key states India, Indonesia and Burma refused to join.
An agreement reached at Manila in 1963 between the Philippines, Indonesia and Malaysia was soon brought into jeopardy by the assignment of Sarawak and Borneo (Sabah) to Malaysia after a plebiscite in these areas, in spite of the claims of the two neighbouring nations. Nevertheless, after the re-establishment of diplomatic relations with Malaysia and the inauguration of Ferdinand Marcos as President in 1966 it became possible to establish a non-political agency for cultural development, social progress, economic growth and administrative cooperation under a treaty signed at Bangkok on 8 August 1967. This was ASEAN, the Association of Southeast Asian Nations by which the five original member countries are Indonesia, Malaysia, Thailand, Singapore and the Philippines. In pursuit of a wider policy of friendly relations with other countries President Marcos also developed contacts with the Soviet Union, China, Japan, the developing countries and the Middle East.