A primary election, in United States politics, is an election held to nominate candidates for a general election in the near future. Primary elections come in several varieties, depending on the rules of the election. An individual may only vote in the primary for one political party in any given election. Primary elections are often combined with elections for non-partisan offices or various ballot initiatives and referendums.
Qualification to appear on a primary ballot is usually fairly low - a candidate must show some small level of support or pay a low filing fee. The winners in each party's primary appear on the ballot in the general election; for single-seat offices, the winner is the candidate with a plurailty of votes in his party's primary.
Primary elections are an outgrowth of the Progressive Era in the United States. Prior to that time, candidates for office were selected by the party organization either by the agreement of party leaders, or through nominating caucuses. In most countries outside the United States, candidates are still selected by small groups associated with the party leadership.
There are three main types of primary elections held in the United States, the closed primary, the open primary, and the Louisiana primary.
In a closed primary election, only people previously registered with a political party may vote in that party's primary election. People who have not registered with any political party may not vote in any party's primary.
Open primary elections take several forms. In some jurisdictions, voter registration does not record party membership, and each voter requests the ballot of the party whose primary they wish to vote in; in other jurisdictions, party membership is recorded, but voters may still choose which primary to participate in. In other jurisdictions, persons who have not indicated a party when registering to vote may choose which primary to vote in, but persons who have chosen a party will receive their party's ballot, and may not change without changing their registration.
The Louisiana primary is a two-stage election, which is a hybrid between a primary election and a general election with a runoff. In the first round, all candidates who have met the minimum qualifying process appear on one ballot, with their party affiliation. As with a general election with a runoff, if one candidate receives 50% of the vote, they win the office, and no second round occurs. However, if no candidate achieves a majority, the second round ballot contains the top vote-getter from each party. In areas with heavy partisan imbalance, this can lead to several candidates being eliminated even though they received more votes than candidates who appear on the second-round ballot.