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.
Two-party system
However, as in other regions, the original rivalry between liberals and conservatives was overtaken by a rivalry between center-left (often social-democratic) parties vs center-right liberal conservative parties, focusing more in economic differences than in cultural and religious differences as it was common during the liberal vs conservative period. Examples of this include National Liberation Party vs Social Christian Unity Party in Costa Rica, the peronista Justicialist Party vs Radical Civic Union in Argentina, Democratic Action vs COPEI in Venezuela, the Colombian Liberal Party (despite the name, a democratic socialist party) vs the Colombian Conservative Party in Colombia, Democratic Revolutionary Party vs Panameñista Party in Panama and Liberal Party vs National Party in Honduras. After the democratization of Central America following the end of the Central American crisis in the 90s former far-left guerrillas and former right-wing authoritarian parties, now in peace, make some similar two-party systems in countries like Nicaragua between the Sandinista National Liberation Front and the Liberals and in El Salvador between the Farabundo Martí National Liberation Front and the Nationalist Republican Alliance.