New Zealand's limited military involvement in the Vietnam War was overshadowed by the wide-ranging debate about the conflict which erupted at home following the rise from the mid 1960s of an organised anti-Vietnam War movement.
Unlike similar developments in both the United States and Australia, this protest was not given momentum by anti-conscription sentiment, though it echoed its American counterpart in terms of style and in many of its criticisms of Washington's policies. At the same time, by highlighting broader issues raised for New Zealand by the Vietnam War, the anti-war movement challenged to an unprecedented extent the alliance-based security doctrine on which official Vietnam policy was based, thereby inaugurating a new era of public debate about foreign policy. The anti-war movement also helped unsettle some prevailing orthodoxies of New Zealand domestic life, in part through its interaction with other protest causes of the late 1960s and early 1970s, such as the women's and anti-apartheid movements.
Much of the anti-war movement's critique echoed international condemnation - and especially American internal criticism - of Western intervention in Vietnam. As elsewhere, there was opposition on moral grounds for reasons ranging from pacifist convictions to objections to the weapons being used or to the undemocratic character of the South Vietnamese government. The charge was also made that the United States and its allies were interfering in a civil war.
To some extent, criticisms of American policy varied according to the critic's ideological stance. Moderates were more likely to ridicule the domino theory while radicals accused the United States of outright imperialism in propping up a repressive puppet regime in Saigon and suggested that most Vietnamese desired a unified nation under some sort of socialist system. Moderates and radicals alike chastised the United States for failing to observe the 1954 Geneva accords, for using excessive force, for alleging that China was behind the war, and for denying that there was widespread support in South Vietnam for the National Liberation Front. There were also those who argued that American policy was less immoral than ill conceived and would have the counterproductive result of strengthening communism in Asia.
Of more distinct and enduring significance for New Zealand was the increasing tendency for local anti-war activists to go beyond criticising the government for supporting the United States in this particular case. Depicting the government's general alliance policies as fundamentally misguided, they rejected the strategy of forward defence, disputed the anti-communist assumptions on which it rested, and denied that communism in South-east Asia posed a threat to New Zealand. More pointedly, they called for a more 'independent' foreign policy, which was not submissive to that of the United States. Their self-consciously nationalistic critique challenged the most basic principles underpinning the country's post-war security policies.
Although this critique failed to diminish official support for American policy, rising domestic criticisms did prompt the Holyoake government to mount a detailed public defence of its stance on Vietnam. For almost a decade after first sending non-combat military assistance in 1963, the government was remarkably consistent in depicting New Zealand's Vietnam policy as a principled response within an alliance framework to a case of external communist aggression. After deciding to send combat troops, the government stressed that it was acting in conformity with treaty obligations and was upholding the principles of collective security to which New Zealand had committed itself since the Second World War.
While taking every opportunity to express his hope for a negotiated settlement, Holyoake repeatedly argued thereafter that, as long as communist aggression persisted against South Vietnam, only military action could preserve the small nation's freedom. The Prime Minister often noted that New Zealand was acting alongside its most important allies in Vietnam, but he did not place the same emphasis in his public statements as his advisers did privately on the importance of maintaining healthy alliance relations with the United States and Australia. Nor did he ever publicly refer to his government's misgivings about the viability of the whole enterprise. He and his supporters did, however, curtly reject the anti-war movement's criticisms of official policy and vigorously defended the alliance-based policy of forward defence in South-east Asia.