As prime minister, Borden led Canada through World War I and its immediate aftermath. His government passed the "War Measures Act", created the Canadian Expeditionary Force, and eventually introduced compulsory military service, which sparked the 1917 conscription crisis. On the home front, it dealt with the consequences of the Halifax Explosion, introduced women's suffrage for federal elections, and used the North-West Mounted Police to break up the 1919 Winnipeg general strike. For the 1917 federal election (the first in six years), Borden created the Unionist Party, an amalgam of Conservatives and pro-conscription Liberals; his government was re-elected with an overwhelming majority.