Australia's involvement in the Vietnam War began with a small commitment of 30 military advisors in 1962, and increased over the following decade to a peak of 7,672 Australian personnel following the Menzies Government's April 1965 decision to upgrade its military commitment to South Vietnam's security. By the time the last Australian personnel were withdrawn in 1972, the Vietnam War had become Australia's longest war, and was only recently surpassed by Australia's long-term commitment of combat forces to the War in Afghanistan. It remains Australia's largest force contribution to a foreign conflict since the Second World War and was also the most controversial in Australian society since the conscription controversy during the First World War. Although initially enjoying broad support due to concerns about the spread of communism in Southeast Asia, a vocal anti-war movement developed in response to Australia's programme of conscription.