<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Political parties in the United States are mostly dominated by a two - party system . However, the United States Constitution has always been silent on the issue of political parties; at the time it was signed in 1787, there were no parties in the nation . Indeed, no nation in the world had voter - based political parties . </P> <P> The need to win popular support in a republic led to the American invention of voter - based political parties in the 1790s . Americans were especially innovative in devising new campaign techniques that linked public opinion with public policy through the party . </P>

What is the political party system of the united states