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.
Libertarianism
A number of countries have libertarian parties that run candidates for political office. In the United States, the Libertarian Party was formed in 1972 and is the third largest American political party, with over 370,000 registered voters in the 35 states that allow registration as a Libertarian and has hundreds of party candidates elected or appointed to public office.