Top five elections: number 4

According to Mapleleafweb's top five elections survey, the 1911 election was judged to be the 4th most important election in Canada's history. This was the famous reciprocity election, in which Laurier's favourable Liberals lost to Sir Robert Borden's Conservatives on the issue of reciprocity, or free trade, with the United States. I myself would likely have put this at number 6, with 7 being the 1988 election. In that year voters reversed the 1911 results, approving Brian Mulroney's free trade agreement with the US.