摘要：Abstract The US has one of the longest traditions of a two-party political system of any nation. Although in recent years there has been a steep rise in the number of people who describe themselves as political independents, the two parties are still dominant, and the prospect of a third party is remote. However, the US party system faces several challenges which have made governing more difficult. The two parties have become much more ideologically polarised. They remain weaker than many European parties in their ability to select their candidates and maintain party discipline among their representatives. The two parties also face strengthened competition in fundraising and campaign spending from outside independent groups. All of these developments have made it more difficult for the parties to secure majorities and pass major legislation.
关键词：US political parties;Polarisation;Two-party system;Independent expenditures
