Historically, United States politics have always featured two main political parties. While in fact there are many different political parties and any one of them can win an election, in practice voters have always elected a presidential candidate from one of the two main parties. This may be because those parties are most representative of the population, or it may be because people fear throwing their votes away on a candidate who can't win. Either way, no third-party candidate has ever won a presidential election.

The Effect of Third Parties

Some third-party candidates have managed to win congressional elections. But in presidential elections, the effect of third parties has been minimal in most cases. If a third-party candidate does manage to gain a large number of votes, as Teddy Roosevelt did in 1912 or Ross Perot did in 1992, the result skews the election. In these cases, the presence of a third-party candidate usually draws votes away from one of the main two parties because of similar platforms. This gives the advantage to the other party, which may not have won if there was no third-party candidate to split the opposing vote.