Origins of the Cold War
Australia's entry into the Cold War came in 1950, when it rushed combat air and sea forces into the Korean War, two days after the Americans did. The Australian Prime Minister received a hero's welcome in Washington. The ANZUS military alliance with New Zealand and the United States was signed in July 1951; it was a plan for consultation and did not involve military planning like NATO. Public opinion in Australia was intensely hostile to Japan after its wartime atrocities, but Japan was now an ally in the Cold War, so Australia's accepted the very generous soft peace treaty with Japan in 1951. Instead of worrying about a resurgent Japan, Australia now worried more about a possible Chinese threat.
Military history of Australia during the Vietnam War
By 1962 the situation in South Vietnam had become bad enough that Diem submitted a request for assistance to the United States and its allies in order to counter the growing insurgency and the threat that it posed to South Vietnam's security. Following this the US began to send advisors to provide tactical and logistical advice to the South Vietnamese. At the same time, the US sought to increase the legitimacy of the South Vietnamese government by instituting the Many Flags program, hoping to counter the communist propaganda that South Vietnam was merely a US puppet state and to involve as many nations as possible. Thus Australia, as an ally of the United States with obligations under the Southeast Asia Treaty Organization (SEATO) and ANZUS Pacts, and in the hope of shoring up its alliance with the US, became involved in the Vietnam War. Between 1962 and 1972 it would send almost 60,000 personnel to Vietnam, including ground troops, naval forces and air assets, and would contribute large amounts of material to the war effort.