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.
Third party (United States)
In the United States, if an interest group is at odds with its traditional party, it has the option of running sympathetic candidates in primaries. If the candidate fails in the primary and believes he or she has a chance to win in the general election he or she may form or join a third party. Because of the difficulties third parties face in gaining any representation, third parties tend to exist to promote a specific issue or personality. Often, the intent is to force national public attention on such an issue. Then, one or both of the major parties may rise to commit for or against the matter at hand, or at least weigh in. H. Ross Perot eventually founded a third party, the Reform Party, to support his 1996 campaign. In 1912, Theodore Roosevelt made a spirited run for the presidency on the Progressive Party ticket, but he never made any efforts to help Progressive congressional candidates in 1914, and in the 1916 election, he supported the Republicans.