Closed Primary
A primary election in which only voters registered with that party may participate.
A closed primary restricts participation to voters who are registered members of the party holding the primary. An independent voter or a voter registered with another party cannot participate unless they re-register with the party before a deadline set by state law.
Parties that prefer closed primaries argue that nominations should be decided by committed party members, not by voters who may not support the eventual nominee in the general election.
Some states use a hybrid system - sometimes called a semi-closed primary - in which registered party members and unaffiliated independents may participate, but registered members of opposing parties may not.
The rules vary significantly by state and by party, and they can change before any given election cycle.
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A primary election in which any registered voter may participate regardless of their party affiliation.
A state-run election in which voters choose their party's nominee for president by selecting among competing candidates.
A party representative selected during primaries or caucuses who votes for a presidential nominee at the national convention.