the Liberals, Michael Ignatieff, announced his retirement. Trudeau entered the leadership contest, which was held in April, 2013. The vote was based on the 308 Liberal riding associations, which each had 100 points. All members of the party had the right to vote in the election through their riding associations. The points for each riding association were allocated in proportion to the local vote. 1 Rounding error. See also Electoral history of Stephen Harper - Trudeau's predecessor as Prime Minister. References External links Library of Parliament: History of Federal Ridings since 1867 Huffington Post: Justin Trudeau Wins Liberal Leadership Race In Resounding Fashion Globe & Mail: Justin Trudeau elected Liberal leader in a landslide. Trudeau, Justin