In Canadian politics, a leadership review is a vote held at a political party convention in which delegates decide whether to endorse the incumbent party leader or schedule a leadership convention to elect a new leader. In most parties at present, such a vote is required at the first convention following a general election. While a leadership election is only required if the incumbent leader fails to receive support from a simple majority of delegates (or if a motion to hold a leadership election passes by one vote), in practice leaders who do not win the review by a substantial margin are expected to either call a leadership election and re-offer or resign altogether.
Traditionally in most Canadian political parties, there was no mechanism for a political party to forcibly remove an incumbent leader. This changed in the late 1960s as a result of a grassroots revolt within the Progressive Conservative Party of Canada against the leadership of John G. Diefenbaker after leading the party to two successive electoral defeats. Party president Dalton Camp agitated for the right of the party to hold a leadership review. Camp called for such a review and, in 1966, ran for re-election as party president declaring that if he was returned to the position, he would call a leadership convention for 1967. He won an important endorsement from Allan S. Blott, the President of Saskatchewan's Progressive Conservative Student Federation, the core of Diefenbaker's political base. At the time, Blott was married to Catherine "Kit" Sampson, the Progressive Conservative Party of Canada's National Youth Director. With strong youth support, Camp was handily re-elected and the party passed a motion to hold a leadership convention by the end of 1967. In January 1967, Diefenbaker asked the party executive to call a leadership convention "at the earliest possible date". Diefenbaker stood as a candidate in the September 1967 convention and was defeated by Robert Stanfield. Subsequently, the Progressive Conservatives instituted a constitutional requirement that a leadership review be held at every party convention. Ironically, the youth wing of the party (PCYF) was disbanded in December 2003 upon the merger of the Progressive Conservative Party of Canada with the Canadian Alliance Party to form the Conservative Party of Canada.