One of the reasons Cairns did not become leader of the Labor Party was that in the late 1960s and early 1970s his main focus was not on parliamentary politics but on leading the mass movement against the Vietnam War, to which the Menzies government had committed combat troops in 1965, and against conscription for that war. Until about 1968, most Australians supported the war. Whitlam himself was cautious about publicly committing the ALP to an explicitly anti-war stance. Opposition to Australia's role in Vietnam was led by the Communist Party and the trade unions. After 1968, however, non-communist opposition grew, and Cairns came to see the anti-war movement as a moral crusade. During the election year of 1969, a group of men broke into Cairns’ home, assaulted him and seriously injured his wife.