The Pipeline Debate, 8 May-6 June 1956, was one of the most famous confrontations in Canadian parliamentary history. Liberal Minister of Trade and Commerce C.D. Howe decided that a pipeline to carry natural gas from Alberta to central Canada was a national necessity. Howe argued that it must run entirely in Canada and deliver to Canadian consumers. The project required very large sums of capital and specialized products and expertise. In 1954 Howe assembled a private syndicate of Canadian and American businessmen to give effect to TransCanada Pipelines, a corporate shell incorporated in 1951; a temporary predominance of the Americans in the syndicate raised charges that the pipeline was a sellout to American interests.

After many vicissitudes, a bill to authorize the pipeline and provide a loan for part of its construction was introduced in May 1956. Social Credit supported it, but the CCF and the Progressive Conservatives attacked the bill from every angle. The CCF preferred public ownership; the Conservatives objected to what they saw as American control. But these substantive concerns were overshadowed by the procedural issue of closure, by which the Liberals placed a strict time limit on debate. As they and the Opposition knew, laying the pipe had to begin by early June or nothing could be done until the next year. The government charged obstruction and the Opposition charged dictatorship, but the bill passed. A 3700 km pipeline was completed from Burstall, Saskatchewan, to Montréal by October 1958, and TransCanada became a principally Canadian-owned company. The debate, however, discredited Howe and the Liberals, and contributed to their defeat in the 1957 general election.