Prior to the 1917 federal election in Canada, the Liberal Party of Canada split into two factions:

• the Laurier Liberals, who opposed conscription of soldiers to support Canada's involvement in World War I and who were led by former Prime Minister Sir Wilfrid Laurier; and
• the Liberal Unionists who joined Sir Robert Borden's Unionist government.

The Conscription Crisis of 1917 and Borden's decision to invite the Liberals into a wartime coalition government with the Conservatives split the Liberal Party largely along linguistic lines. Many provincial Liberal parties in English-speaking Canada and a number of Liberal Members of Parliament supported conscription and decided to support Borden's government. Many of them called themselves Liberal Unionists. Quebec Liberals and the leader of the Liberal Party of Canada, Sir Wilfrid Laurier, refused to join Borden, and ran in the resulting election as "Laurier Liberals" or Opposition (Laurier Liberal).

Of the 235 seats in the Canadian House of Commons, only 82 returned Laurier Liberals in the election held December 17, 1917:

• 62 were elected in Quebec ridings,
• 1 from Alberta,
• 1 was from a Manitoba riding with a large francophone population,
• 5 were from New Brunswick (four of whom were French-Canadians),
• 4 were from Nova Scotia,
• 2 were from Prince Edward Island, and
• 8 were from Ontario.

With only 20 seats from English Canada, the Liberal Party was reduced to a largely French-Canadian parliamentary rump in 1917.

The Conservatives attempted to make their alliance with Liberal Unionists permanent through the formation of the National Liberal and Conservative Party. However, under a new leader, William Lyon Mackenzie King, the Liberals were able to recover enough of their support in English Canada to form a minority government following the 1921 federal election.

See also: List of Canadian political parties