Swing vote is a term used to describe a vote that may go to any of a number of candidates in an election, or, in a two-party system, may go to either of the two dominant political parties. Such votes are usually sought after in elections, since they can play a big role in who wins and loses.

A swing voter or floating voter is a voter who may not be affiliated with a particular political party (Independent) or who will vote across party lines. In general, many centrists, liberal Republicans and conservative Democrats are considered "swing voters" since their voting patterns cannot be predicted with certainty.

While the swing voter is ostensibly the target of most political activity during elections, in countries without compulsory voting the political parties know that the shift from one party to another is dependent only to a limited extent on swing voters. Another, arguably larger factor is the success of one party in comparison to another in getting out its core support. In a two-party system, those who become disillusioned with their favored party are more likely to vote third-party or abstain than cross over.

However, in the 24 countries with compulsory voting, voter turnout is often already very close to 100%, so if the major parties are roughly balanced in popularity, swing voters can have a marked influence on the outcome.

The 2004 US presidential election was notable for the extent to which the Bush campaign was successful in getting out its vote. Republican strategists argued that it would be a mistake to play for the center ground, i.e., swing voters, and that they needed to put all their effort into energizing their natural support.

Swing Vote is a 1999 film, directed by David Anspaugh in which the Supreme Court of the United States has overturned the Roe v. Wade decision and thrown the issue of abortion rights back to the individual states.

Alabama has subsequently outlawed abortion on demand and has prosecuted Viginia Mapes (Lisa Gay Hamilton) for first degree murder after she opted to terminate her pregnancy before the bill was signed into law. Mapes and her attorney have taken the case to the Supreme Court in hopes of keeping her out of prison, and with the court evenly divided on the issue, newly appointed Supreme Court Justice Joseph Kirkland (Michael Garcia) looks to be the man who will cast the deciding vote in a case that could reinstate a woman's right to choose.

Kirkland, however, finds himself surrounded by proponents of both the pro-choice and pro-life agendas, with his fellow justices, his secretary and even his wife, Linda Kirkman trying to influence his vote. This film was produced for ABC Television.

Swing Vote is an upcoming 2008 comedy film directed by Joshua Michael Stern starring Kevin Costner, Kelsey Grammer, Stanley Tucci, Dennis Hopper, Nathan Lane, and George Lopez. It is currently in post-production and is scheduled for a release in August 1 2008. Six Actors Join Kevin Costner on His Swing Vote

A new appointee (Andy Garcia) suddenly finds himself the center of attention as his other eight jurors have split their vote down the middle on a case involving a woman (Lisa Gay Harden) who is charged with murder after she had an abortion. Garcia refuses to make a rapid decision and studies all sides before rendering his opinion. Written by John Sacksteder