Generally, a registered voter will simply select a party's ballot at the polling place on the day of the primary.
Possible effects of an open primary
According to FairVote, open primaries can lead to more centrist candidates being selected. As members of one party may cross over to vote in the other party's primary, they often vote for the candidate they consider least objectionable. Thus, Democrats voting in Republican primaries would vote for the most Democratic Republican candidate, and vice versa, leading to both parties having center-leaning nominees in the general election.
In some cases, one party's voters may try to coordinate to vote for a less-electable candidate in the opposing party's primary. If successful, "party crashing" voters could improve their own party's chances by selecting a weaker opponent for the general election.
States that use an open primary
Three states uses the top-two blanket primary process. In these states, only one primary is held with candidates from all parties participating. Thus, all voters are able to participate in the single, blanket primary. The three states are:
Other primary systems
Some states have a mixed primary system. In most cases this means the power to decide who can vote in a primary is given to the parties. Some parties may allow any registered voter to vote in their primary, some allow only those voters who are registered with their party, and others allow only voters who are unaffiliated to vote with their party members. Other mixed primary systems require unaffiliated voters to affiliate with a party in some way in order to vote in that party's primary. They can do this by choosing a party ballot, following their voting record, or publicly announcing which party they would like to affiliate with. The affiliation could last until the next election, until a voter requests to be changed back to unaffiliated or only for the day of the primary, depending on the state.
In a blanket primary, voters pick one candidate for each office without regard to party. The candidates with the most votes advance to the general election. For example, two Democrats or two Republicans can advance beyond the primary to the general election.
- MTV Rock the Vote: Terms and Definitions
- How Stuff Works "Types of Primaries," accessed April 27, 2012
- FairVote.org "Congressional and Presidential Primaries: Open, Closed, Semi-Closed, and 'Top Two,'" Accessed April 27, 2012
- The Daily Beast "Some Suspect Foul Play in S.C. Primary," June 11, 2010
- National Conference of State Legislatures Website, "State Primary Election Types," accessed January 6, 2014
- Fair Vote, "Congressional and Presidential Primaries: Open, Closed, Semi-Closed, and 'Top Two,'" Accessed January 6, 2014
- Ballotpedia research conducted December 26, 2013 through January 3, 2014 researching and analyzing various state websites and codes.
- VotesPA "Primary Election," accessed April 27, 2012