In any two-party system of politics, a third party is a party other than the two main ones. While the term should be used only when discussing the third largest party, it is often used to describe any smaller party. For example, in the United Kingdom a third party is a national political party other than the Conservative Party and Labour Party that has a presence in the House of Commons. In the United States, a third party is a political party other than the Democratic Party or Republican Party that has national influence.