A bitter conflict that defined a generation
A student protester washes a US flag in Melbourne on July 4, 1968.
The fear of "another Vietnam" holds sway over military decisions today.
In 1965, Australia committed a battalion of troops to Vietnam. In 1975, the North Vietnamese took Saigon. This tumultuous decade, more than any before or since, marked an epochal clash between two visions of Australia. As official war historian Dr Peter Edwards has put it, it was a time when the nation was at war in more ways than one.
The Vietnam War brought to a shuddering halt the staid, conservative culture of the Menzies era. Australia was swept up in radical intellectual and social movements, and a rising spirit of dissent. As a grim conflict was fought out in the jungles of Indochina, it became as much a struggle on the home front, with divisions reverberating across the nation.
In 1968-70, tens of thousands of demonstrators took to the streets of Sydney and Melbourne in moratorium marches. On the nation's campuses, a new class of political activists emerged, bent on engineering a fundamental realignment of policy and culture.
Which was the greater mobilising factor - the judgement that America and its Australian ally were waging an illegitimate war on the peoples of Indochina? Or that conscription to national service meant old men were sending the nation's youth into a conflict against their will? In the shorthand of history, the two issues have been conflated.
Either way, the effect was to politicise an entire crop of young Australians.
For that baby boomer generation, even 30 years on, the Vietnam experience remains a key reference point in defining their view of the world. For them, as Donald Horne argued, Vietnam became the "transcendent issue, overriding all others, and sorting out the good from the evil". To that extent, it was to have a dramatic impact on the nation's psyche.
Militarily, Vietnam put paid to conscription. The US and Australia switched to all-volunteer armies. Strategically, the failures in Vietnam marked the end of 20 years of US-led military interventions in east Asia, and prompted both Washington and Canberra to embrace a new policy of engagement with the emerging power of Communist China.
Politically, the war precipitated the end of 23 years of Liberal rule.
More than 46,000 Australian military personnel served in Vietnam, including 17,424 conscripts. Five hundred and nineteen Australians died, and 2400 were wounded. Conventional wisdom has it that they died in vain, sent into an unwinnable war by weak leaders unwilling to stand up to Washington.
But history is never that simple, even in hindsight.
Cabinet documents from 1965 indicate a Menzies government increasingly agitated by fears of revolutionary forces at play not only in China but also Indonesia. Soekarno's policy of Konfrontasi had brought clashes with Australian troops in Borneo, and Indonesia's move on West Papua raised concerns of similar ambitions for New Guinea.
Australian combat forces were sent to Vietnam in April 1965 in the expectation of a quid pro quo - that the US would come to Australia's aid in any conflict with Indonesia.
Initially, Australia's involvement had strong community support, peaking with the 1966 landslide victory for Menzies' successor, Harold Holt. But as the fortunes of war turned, so did the national mood, and Holt's "All the way with LBJ" soon became a target of ridicule.
By 1970, polls showed a majority had come to think the war was not only a mistake, but also immoral. The Whitlam Labor government, voted into office in December 1972, ended conscription and promised to bring the last troops home. Yet the only forces left were a few dozen training officers. The McMahon government had withdrawn combat troops from Christmas 1971 - all too late for a discredited and unpopular government.
In South-East Asia, perspectives on the Vietnam War are different. What might have been the fate of Indonesia, Thailand, Malaysia and Singapore had South Vietnam fallen to communist North Vietnam in 1965, a decade before Hanoi's final victory?
But, in Australia, the vestiges of the "Vietnam syndrome" linger. As evidenced in the Iraq debates, those bitter years entrenched in many a deep suspicion of overseas military commitments, and scepticism, if not outright hostility, about America's role in the world.
While the fear of "another Vietnam" no longer overrides all decisions on war and peace, it guarantees politicians think twice before sending soldiers into conflict in faraway places.