Last weekend’s commemorations of the centenary of the Gallipoli landings was the ultimate expression of our habit of reflecting on the causes, conduct and consequences of war at the time of major anniversaries. Unfortunately, Australia’s major wars of the twentieth century occurred, with remarkable precision, at quarter-century intervals. Thus the centenary commemorations of 1914–18 will overshadow the 75th anniversaries of major turning points in the Second World War and the 50th of those of the Vietnam War.

Fifty years ago this week, Prime Minister Robert Menzies announced the commitment of the first battalion of Australian combat troops to Vietnam on 29 April 1965. Ten years later, on 30 April 1975, the war ended as North Vietnamese tanks crashed through the gates of the presidential palace in Saigon. In a particularly cruel irony, the Australian ambassador closed our Saigon embassy and headed for the airport five days earlier—the 60th anniversary of the Anzac landing.

If Gallipoli had occurred, say, a year earlier or a year later, those anniversaries might now prompt a substantial discussion of the rights and wrongs of the Vietnam War and its implications for many areas of Australian political and social life: grand strategy, military operations, conscription, and the physical and mental health of veterans. Instead, we have only a few references in public discussion.

That gap matters. While the scale of our 1965–72 commitment does not compare with that of 1914–18—to use one crude but telling index, 521 service personnel dead from a population of about 12 million compared with 60,000 from a population of less than 5 million—the impact of Vietnam is more immediate. Any new commitment, especially as part of a coalition led by the United States, is still likely to meet the challenge: ‘Is this another Vietnam?’ And the current Minister for Veterans’ Affairs takes every opportunity to say that our Iraq and Afghanistan veterans must be treated better than those from Vietnam.

So how should we look at the Vietnam War, half a century on? First, it was not a case of Australian involvement in ‘other people’s wars’. As far as Robert Menzies was concerned, it was more a matter of getting the US to fight Australia’s wars. Australian strategy was based on the need to keep Britain and the United States committed to the security of Southeast Asia, which clearly mattered more to Australia than to northern hemisphere allies.

Menzies, it seems, feared American isolationism more than American overreach. He, and those from whom he chose to take advice, found it difficult to believe that the United States, if fully committed to a conflict, could be defeated. It was a huge miscalculation, but understandable given Menzies’ personal experience as a young man during WWI, which the US did not enter until 1917, and as Prime Minister in 1939–41, before Pearl Harbor. To him, and others of his generation, what really mattered was Washington’s commitment: if the Americans were involved, it seemed, success was certain.

Australia had a very specific reason to be concerned about American policy. In the early 1960s Australians were deeply concerned about another, much closer, Southeast Asian conflict. Australian forces were supporting the new federation of Malaysia against Indonesia’s ‘confrontation’. It was a low-level conflict, but Australian policymakers constantly feared that Indonesia might raise the stakes, not only on the Malayan peninsula but also across Australia’s only land border—between Indonesia’s West New Guinea and the Australian territories on the eastern half of the island (today’s Papua New Guinea). When Australian ministers asked American officials at what stage Indonesian aggression might prompt support under ANZUS, the Americans clearly hinted that much would depend on Australian support for the American position in Indochina.

The Vietnam War was not about regime change, but about regime defence. There was never any intention to overthrow the communist government in Hanoi: the aim was only to prevent the fall of an anti-communist government in the south. In that sense, Vietnam was more akin to the first Gulf war of 1991 than to the Iraq invasion of 2003.

Above all, we should remember what else was happening in Southeast Asia in 1965. The Indonesian Communist Party was the third largest in the world. President Sukarno said 1965 would be a ‘year of living dangerously’ with the support of a ‘Beijing-Jakarta’ axis. Tensions between Kuala Lumpur and Singapore would soon lead to the ejection of Singapore from Malaysia. Thailand faced a substantial communist insurgency in its northeast. It is hardly surprising that many of the region’s ‘dominoes’—most publicly Singapore’s Lee Kuan Yew—fervently urged the Americans not to withdraw. We learn from Jeremy Hearder’s new biography of Sir James Plimsoll that Indian generals were expressing a similar view in early 1965.

By 1968–69, much had changed in the region. Indonesia was now securely under the anti-communist President Suharto. Malaysia and Singapore were functioning better apart than together. Thailand had its internal insurgency under control. The formation of ASEAN in 1967 indicated that these non-communist nations were willing to collaborate better. In short, the only dominoes likely to fall with South Vietnam would be Laos and Cambodia.

For Australia and many other countries in the region, the 1965 commitment by the United States and its allies served a purpose, but the strategic gains were achieved by the end of the 1960s. The real tragedy of the Vietnam War was that it continued well into the 1970s, at huge cost to all external participants, and most of all, to the Vietnamese people.