A primary election is conducted so that voters can select candidates for a subsequent election (this is called the nominating primary). Primary elections allow each political party to determine its nominee for the upcoming general election.
Primary elections are classified by various categories:
- Open: Voters may vote in the primary election of a party of their choice, regardless of their own party affiliation, and they can make this choice privately in the voting booth. Voters cannot, however, vote in more than one party's primary; they must choose one and only one.
- Closed: Voters must declare their party affiliation in advance of the primary election, and can only vote in that party's primary. To participate in a party's closed primary election, voters must identify their party affiliation when they register to vote.
- Semi-closed: Voting is restricted to voters who have already declared their party affiliation in advance, and to new and/or Independent (unaffiliated voters) who choose which primary to vote in on Election Day. To participate in a party's semi-closed primary election, voters must identify their party affiliation when they register to vote.
- Semi-open: Voters can choose which party's primary to vote in on Election Day, regardless of their party affiliation, but must make a public declaration of that choice in front of election judges.