The nature of the Canadian-American relationship during the Korean War (1950-53) has been debated for over 30 years. In 1974, political scientist Denis Stairs argued that Canadians pressed for greater UN control over the prosecution of the American-led war to prevent military escalation. officials, he explained, it was essential to moderate and constrain the course of American decisions in the far east.1 In 1992, historian Robert Prince challenged this interpretation. Drawing largely from recently released documents from the Department of External Affairs (DEA), he contended that Canada and America had had similar goals in Korea. Moreover, thanks largely to their to maintain influence in Washington and their fears of splitting the western alliance, the diplomats from Ottawa were limited in their ability to constrain their most significant ally.2 More recently, historian John Price has corroborated Prince's argument by demonstrating how, during the negotiations to create the United Nations temporary commission on Korea in 1947, Canada's undersecretary of state for external affairs, Lester Pearson, was focusing on cementing a Cold War partnership with the United at virtually any cost.3In spite of the legitimacy of their evidence, Stairs's detractors are not entirely convincing. Certainly, it is reasonable to question whether Canada and the United States placed the same value on the security of Korea. While the Americans felt it was crucial to their interests, the advisor to Canada's ambassador to the United States described Korea in his memoirs as a conflict whose objectives were at best peripheral to our own.4 And Canadian Minister of Defence Brooke Claxton suggested at the time that the United States was getting [Canada] into something to which there really was no end.5 Canada was also certainly limited in its ability to influence American activity in Korea. But the evidence that it did not wish to restrain-or constrain - the United States is more ambiguous. Specifically, Canada was prepared to use the full extent of its diplomatic capital to keep the Americans from undertaking any atomic offensive deemed unnecessary by Ottawa. Primary documents of top-secret Canadian-American consultations reveal that constraint was a pattern in Canadian foreign policy, resulting from differing Canadian-American approaches to the early Cold War.Fears that America was actively considering atomic strikes resulted from comments made by the president of the United States five months into the Korean War. On 30 November 1950, Harry Truman told American reporters that Washington would not require United Nations authorization to initiate an atomic attack. The mention of atomic weapons was impromptu, and reporters were under orders not to quote the president verbatim. Nonetheless, precise transcripts of the press conference were disseminated to foreign embassies in Washington by media sources.Reports of America's hawkishness generated significant concern among nations who had committed troops to follow US orders in the far east. The Canadian government quickly dispatched a letter to Washington declaring its strong opposition to the use of atomic weapons in Korea, while the Britain Prime Minister Clement Attlee was petitioned to make an immediate trip to Washington to discuss the matter.As a result of Attlee's December 1950 discussions in Washington, the British and American governments issued a joint communique declaring the importance of strong allied cohesion in Korea to prevent any possible Soviet aggression in the east. The announcement was also an attempt to calm allied concerns that the United States was considering the unilateral deployment of atomic weapons. Truman declared that it was his hope that world conditions would never call for the use of the atomic bomb, and went on to express his desire to keep the Prime Minister at all times informed of developments which might bring about a change in the situation. …