Two-party system
Third parties, meaning a party other than one of the two dominant parties, are possible in two-party systems, but they are often unlikely to exert much influence by gaining control of legislatures or by winning elections. While there are occasional opinions in the media expressed about the possibility of third parties emerging in the United States, for example, political insiders such as the 1980 presidential candidate John Anderson think the chances of one appearing in the early twenty-first century is remote. A report in "The Guardian" suggested that American politics has been "stuck in a two-way fight between Republicans and Democrats" since the Civil War, and that third-party runs had little meaningful success.
Non-partisan democracy
The administration of George Washington and the first few sessions of the US Congress were nonpartisan. Factions within the early US government coalesced into the Federalist and Democratic-Republican parties. The Era of Good Feelings, when the Federalist party collapsed, leaving the Democratic-Republican party as the sole political faction, was the United States' only experience with a one-party system.