Most Western democracies have multiparty systems where voters choose between lists of party members. This means that voters choose between lists of all Democrats, Republicans and other parties. This means that split ticket voting is not possible. Split ticket voting is where voters can choose members of different parties for specific offices (such as a Democrat Senator and a Republican Representative).
Parliamentary systems use proportional representation, where representation is based on proportion of the national vote. In other words, proportional representation in Parliament (the legislature branch) is based on percentage of vote received. For example, a party with 45% of the vote gets 45% of legislature seats, while a party with 5% of the vote gets 5% of legislature seats.
The U.S. has a two-party system due to electoral rules and because major parties create restrictions on minor parties.
|Electoral Rules||States have single-member districts, while other countries have five Representatives for a particular district; representation of that district is based on proportion of the vote.|
The U.S. has winner-take-all (plurality) elections. For example, in the general election, the candidate with the most votes wins. This candidate wins even if most people vote against them (ie, 28 vs 24, 24 and 24). This lack of proportional representation makes it harder for smaller parties to gain representation.According to Duverger's Law, two=party systems develop in all political systems with single-member districts and winner-take-all (plurality) rules.
|Majority Parties||Major parties restrict the emergence of third parties. It is difficult to get federal funding for minority parties, although any third party with 5% of the general vote is eligible for federal funding in the following election. This helps minority parties gain momentum.Also, third parties are excluded from televised presidential debates. They are not given media exposure, so a majority of Americans are never exposed to minority party views.|