) After war had broken out in Vietnam in 1960, Ngo Dinh Diem, leader of the government in South Vietnam requested support from the US and its allies to improve its defense. Australia eventually acted in response by sending 30 military advisers to Vietnam, their arrival in South Vietnam between July and August 1962 was the beginning of Australia's involvement in the Vietnam War. .
The main reason for Australia's involvement in the Vietnam War was to bring to an end to communism. Communism, also known as the Red Menace is a political and economic theory in which a country's wealth and resources are owned by everyone. Australia and other Western countries feared communism as communists often gained power by force. After World War II most of Eastern Europe was communist and China was also communist. This growth of communist countries threatened Western countries and surrounding Asians countries. The fear of communism aggression was founded upon the "Domino Theory". The Domino Theory was the idea that if any nation fell to communism, the surrounding nations would be likely to fall to communism, starting a chain reaction in which countries fell like dominoes in a line. Therefore Australia feared that with the "fall" of South Vietnam to communist North Vietnam, all of Southeast Asia might also "fall" starting a communist chain reaction. .
Another reason why the Australian government sent Australians to serve in the Vietnam War was to fulfill their obligations as members of the South East Asia Treaty Organisation (SEATO). SEATO is an alliance of nations to provide defense and economic cooperation in South East Asia. It was founded on September 8 1954 by Australia, France, New Zealand, Pakistan, Thailand, the United Kingdom, the Philippines and the United States. As Australia was a part of SEATO, it was required to act by the treaty. One aspect of the SEATO treaty was if a member country was attacked other members would help it.