Chambly, Quebec
Edmonston entered Canadian politics in the 1988 federal election as a candidate for the New Democratic Party (NDP) in Chambly, Quebec, placing second. He won the riding in his second attempt, a 1990 by-election in which he defeated former Quebec cabinet minister Clifford Lincoln by almost 20,000 votes, becoming the first member of parliament from Quebec to be elected for the NDP. (Another Quebec MP, Robert Toupin from Terrebonne, had previously crossed the floor to the NDP in 1986.)