Cold War scholarship has largely neglected Canada's role, including the important part Canada played in U.S. President Dwight Eisenhower's defense policy. This article shows that after the Soviet thermonuclear detonation in August 1953, the Eisenhower administration urgently sought Canada's participation in joint continental air defense plans. Canadian officials thereafter struggled to minimize U.S. intrusions on their national sovereignty and ensure the integrity of Canada's national interests. To accomplish their respective goals, the two sides instituted secret, high-level consultative meetings from October 1953 through September 1954. The meetings enabled U.S. and Canadian officials to exchange views regarding U.S. proposals for an early warning network across northern Canada and allowed the Eisenhower administration to keep its Canadian counterpart apprised of U.S. defense plans. U.S.-Canadian interactions during this period set the tone for the two countries' defense relationship throughout the Cold War.