<human>:  What is the difference between the political party systems of the United States and the European Union?
<bot>: The political party systems of the United States and the European Union differ in several ways. In the United States, the political party system is a two-party system in which two major parties, the Republican Party and the Democratic Party, dominate the political landscape. In the European Union, there is a multi-party system in which several different parties compete for power. The political ideologies represented in the two systems also diverge significantly. In the United States, conservative and liberal parties dominate the political spectrum, while in the European Union there are a variety of right-wing and left-wing parties, as well as those that are more centrist or independent. Additionally, in the European Union, the political parties are more likely to form coalitions or alliances than in the United States.