Political parties of the United States traditionally divide the available spectrum of choices into two camps. The first is known as the "major parties" and the second as the "third parties" camp. This is due to the fact that the United States has a two-party system, with the two largest centrist parties dividing the vote between themselves in the national elections. This is partly a consequence of the first-past-the-post election system but also due to restrictive ballot access laws imposed on third parties.
Many third parties throughout U.S. history have achieved regional success and some (notably the Prohibition Party and the Socialist Party) have had major portions of their platforms incorporated into the "major parties" platforms. While only the Republican Party has gone on to become a dominant player in American political life, the overall political platforms of several third parties have taken root in the American political landscape.
