In September 1954 the United States, France, Great Britain, New Zealand, Australia, the Philippines, Thailand and Pakistan formed the Southeast Asia Treaty Organization (SEATO).
Although most of the SEATO member states were countries located elsewhere than Southeast Asia. they all had interests related to their geographic position, status as former colonial powers or concern about communist expansion in the region.
SEATO was dissolved on 30 June 1977 after multiple members lost interest and withdrew.
Main Source: Office of the U.S. State Department Historian