alternatehistory.com

Twenty-one men have served as the Prime Minister of Canada since the country was granted self-governing status in 1867. Although the office is never referred to in either the Dominion Act of 1867 and only in passing in the Constitution Act of 1986 that formally severed the legal ties between Canada and the United Kingdom, the prime minister is the most powerful person in Canada’s government. He (and so far only men have become prime minister) is appointed by the monarch via the governor-general to head Her Majesty's Canadian Government and is responsible for advising the governor-general on the appointment of cabinet ministers, half of any Senate vacancies and members of the Supreme Court. The prime minister also advises the monarch on whether to continue the current governor-general's service (traditionally five years' time) or to appoint someone else as the viceregal representative.

The prime minister has, by custom, always been the leader of the party with the most seats in the House of Commons and every prime minister since Sir Charles Tupper (1896) have held seats in that house. As such, all prime ministers have been members of either the Liberal Party (including the current prime minister, Thomas Mulcair) or the Progressive Conservative Party and its historical predecessors. Canada's tradition of strong party discipline has resulted in prime ministers whose party has a majority of seats in the House of Commons being able to easily pass most proposed legislation into law. However, the prime minister is also constrained by both public opinion and that of his party in pushing forward legislation, as well as the political makeup of the House of Commons when his party has a plurality (but not a majority) of seats. Additionally, the Supreme Court has the power to strike down unconstitutional legislation and the governor-general has reserve powers to dismiss the prime minister, although these have not been invoked since 1926 when they led to a constitutional crisis.