Poster headed 'Out now' advertising a rally on 31 July 1971 against the Vietnam War and the National Service Act.

From 1954 communist North Vietnam and South Vietnam were at war. In the 1960s hundreds of thousands of United States troops were involved in support of South Vietnam and the Australian government also decided to commit troops.

A new National Service Act of 1964 required 20 year old men, selected by a ballot of birthdays, to serve for two years in regular army units. In May 1965 the Defence Act was amended to provide that these conscripts could also be required to serve overseas. Between 1965 and 1972 (when the last Australian troops were withdrawn from Vietnam) over 800,000 men were registered for National Service, 63,000 were conscripted by the ballot, and some 19,000 served in Vietnam. There were 496 killed and 2,398 wounded. The first conscript to die in Vietnam, Errol Noack, was a South Australian.

Many Australians were opposed to involvement in the Vietnam War and even more objected to the use of conscripts there. Tens of thousands of Australians participated in rallies and related activities as part of the Vietnam Moratorium protests. Groups such as the Campaign for Peace in Vietnam campaigned vigorously against conscription, and thousands joined protest marches in Adelaide in May and September 1970.

'Police arrest 130 at city sit-in' Advertiser 19 September 1970, p. 1.

Saunders, Malcolm, 1949- 'Opposition to the Vietnam War in South Australia, 1965-1973' Journal of the Historical Society of South Australia, no. 10, 1982, p. 61-71