In 1945 the Canadian government reluctantly accepted a role in the truce supervisory commissions for Vietnam. At the time, the Eisenhower administration was expressing a clear lack of enthusiasm for the Geneva Agreement, and the conservative wing of Congress was openly hostile to it. Ottawa’s decision to become involved grew out of a desire to moderate and constrain the play of American military power in Southeast Asia. Particularly, under the direction of Lester Pearson, first as Secretary of State for External Affairs in the St Laurent government and later is Prime Minister, the Department of External Affairs tried to inhibit the possible use of nuclear weaponry in the US. Ottawa’s decision to participate created considerable tensions in the Canadian policy community, but on the whole the maintenance of ‘nuclear peace’ in Asia remained the highest priority objective of Canadian policy-making. Douglas Ross examines that objective and how it directed the course of Canadian involvement in Vietnam. He documents a number of changes in approach by Ottawa and analyses the political influences behind them. The first of these was a rightward shift in the operational consensus of the Department of External Affairs, which emerged from the changing balance of power in Indochina in 1955-6. Second was an implicit endorsement of covert assistance to the Saigon government by the United States as a means of sustaining the precarious balance of force in Vietnam. And third, Ottawa gave very reluctant and qualified legitimation to the United States intervention under presidents Kennedy, Johnson, and Nixon, both to sustain amity in Canadian-American relations and to preserve Ottawa’s credibility as a sympathetic ally in the global and anti-communist struggle. Only as credible sympathetic allies could Canadian policy-makers and diplomats hope to reinforce internal American inhibitions against a resort to the tactics of escalation which threatened to provoke war with China or a limited war in East Asia — events that would at least server all of Asia from the West for generations or, at worst, provoke a cataclysmic final confrontation between the blocs. Here is a perceptive analysis of Canada’s involvement in a difficult situation, of how painful decisions about that involvement were made, and of how policy-makers were guided by an unflagging concern for ‘the interests of peace.’