It's actually the winner-take-all system that tends towards a two-party system. If there are eight parties running in one riding, but only one can win a seat, then people vote for the candidate most likely to win, rather than the candidate who will best represent them. That results in poor representation -- up to 7/8 of the voters may have cast a ballot for someone not elected, and when this is repeated riding after riding you get false majorities with as little as 12.5% of the vote. # can fix this with larger ridings and multiple candidates elected, who have to share the power (ie. coalition). !ElectoralReform