It’s just a half-century since prime minister Robert Menzies announced that Australia would commit combat forces in defence of the anti-communist government of South Vietnam.

The decision was announced on April 29, 1965, just four days after the commemoration of the landing of the First Australian Imperial Force at Anzac Cove a half-century earlier.

Australia’s Vietnam commitment had begun in May 1962 when the Coalition announced the deployment of the Australian Army Training Team Vietnam to South Vietnam. It ended in December 1972, soon after the election of Gough Whitlam’s Labor government, when the AATTV troops were withdrawn. All Australian combat forces had been withdrawn by the end of 1971 during the prime ministership of William McMahon. So the main focus of the Vietnam war in Australia occurred between April 1965 and November 1971.

Along with the Dardanelles campaign of 1915, Australia’s Vietnam commitment has become the most analysed military involvement by Australian forces during the past century; this despite the AIF’s significant achievements on the Western Front, particularly in 1918, and despite the crucial role the Australian Army played — along with Canadian forces — in stopping an attack by North Korean and Chinese forces at the Battle of Kapyong in April 1951 during the height of the ­Korean war.

The recent deaths of Whitlam and former Liberal prime minister Malcolm Fraser provide an appropriate opportunity to reflect on the Vietnam war in Australian history.

Many commentators falsely claim Whitlam withdrew Australian combat troops from Vietnam. In fact, in the years before he became prime minister in December 1972, Whitlam was not a high-profile critic of the Vietnam commitment. In the Australian Labor Party, that role was taken by left-wing politicians such as Jim Cairns and Tom Uren.

In his final years Fraser became a critic of the Vietnam commitment, despite the fact he was minister of the army from January 1966 until February 1968 and minister for defence between November 1969 and March 1971.

Moreover, in the second half of the 1960s, as a backbencher and then as a minister, Fraser was one of the few Liberal MPs who could successfully defend Australia’s involvement in Vietnam.

In the error-riddled Malcolm Fraser: The Political Memoirs, which Fraser co-wrote with academic Margaret Simons, he falsely claimed Harold Holt (Menzies’ successor) “announced the despatch of Australian troops to South Vietnam”. In later life Fraser claimed he was unaware of the disastrous decision made by the US in late 1963 to overthrow South Vietnam’s leader Ngo Dinh Diem. Fraser used this so-called discovery in 1995 as a reason to rationalise why he changed his view on the Vietnam commitment. In fact, the US role in Diem’s assassination was widely known and discussed at the time.

Fifty years after the announcement Australian troops would be dispatched to Vietnam — later to be supported by the Australian navy and air force — it is convenient to examine the ­con­temporary attitude to the ­commitment.

Australia’s Vietnam commitment enjoyed broad support for most of the time our defence forces were deployed. The Coalition won elections in 1966 (under Holt’s leadership) and 1969 (under John Gorton’s leadership). The Democratic Labor Party was the political party most supportive of the Vietnam commitment. The DLP did very well in the half-Senate elections of 1967 and 1970, which saw the election or re-election of Frank McManus, Vince Gair, Jack Kane, Jack Little and Condon Byrne.

What is commonly called the “anti-war movement” at the time was not really opposed to the ­conflict, meaning there were few pacifists in the debate. Those who opposed the role of the US in the conflict — supported by Australia, New Zealand and some other ­nations — barracked for Hanoi. This was the hard point made at the time by one-time Labor ­supporter economics professor Heinz Arndt when he said many of his left-wing associates wanted the communists to win.

Cairns constantly claimed in the mid-60s and beyond that the National Liberation Front was an independent South Vietnamese entity. Not so. The NLF was always controlled by the Communist Party dictatorship in North Vietnam, which had dispatched thousands of troops to the war zone in South Vietnam by the mid-60s. Many more followed. Some of the engagements undertaken by the Australian Army in the field were with well-trained and well-equipped members of the North Vietnamese army.

The Vietnam war was won in Moscow and lost in Washington, DC. As Peter Edwards documented in his valuable book Australia and the Vietnam War, the North Vietnamese army was supplied by the Soviet Union with sophisticated surface-to-air missiles capable of downing the best fighter jets, along with T-54 tanks and long-range artillery. All this ­material was supplied to communist forces through North Vietnamese ports.

The communist leadership’s attempt to initiate popular uprisings in South Vietnam in 1968, 1972 and 1975 all failed. The South Vietnamese army collapsed only after the US congress prevented the supply of US weapons to Saigon’s forces.

In other words, Hanoi won the Vietnam war because of the unintended consequence of the Watergate scandal and the subsequent resignation of president Richard Nixon, which de-authorised US decision-makers. This is documented in George J. Veith’sBlack April: The Fall of South Vietnam 1973-75.

The Left, including the Labor leadership, welcomed the communist victories in South Vietnam and Cambodia in 1975.

As late as 1978, Whitlam was still denying there were communist-inflicted atrocities in Indochina (including Pol Pot’s Cambodia); and as late as 1979, Uren was still proclaiming his support for Pol Pot.

The 521 Australians who died in Vietnam did not die in vain. Southeast Asia, along with Australia and New Zealand, was much better equipped to handle a communist victory in Vietnam in 1975 than would have been the case a decade earlier. This was the position of the late Lee Kuan Yew, the former leader of Singapore.

Menzies’ Vietnam commitment of a half-century ago remains controversial. However, on ­balance, it was a correct decision taken in the interests of Australia.