A multi-party system is the most common system in the world today.
America's 2-party system is not the common model most other democratic nations follow, with three or more political parties. Some nations have dozens parties. Canada's parliamentary system has six major political parties. Mexico has seven parties active in its politics. One American political commentator has written: "The divisive and competitive politics of the Democrats and Republicans have many Americans wondering whether we’d be better off with a multi-party system" (Rachel Eckhardt in HuffPost, 10/26/2015).