One major difference between Canada and the US is the Westminster parliamentary system and the fact that we don't have a quasi religious commitment to a piece of paper and founding daddy issues. The two party system will probably never become as ironclad as in the US because we don't have the Imperial Presidency where every election is an event of cosmic proportions. Instead our system has a lot more space for power sharing (minority governments, coalitions, supply and support, etc). Plus Québec, which is literally Canada's saving grace, no matter what Canadians think. (New Canadian who loves QC here.)