Types

• There are two types of primary elections: open and closed.
  
  

Closed Primary

• In a closed primary, a voter can participate only in the primary of the political party with which she is a registered member.
  
  

Open Primary

• Open primary states do not require voters to register as a member of either party. On primary election day, voters choose the party primary in which they will vote.
  
  

Considerations

• Closed primaries tend to discourage voters from registering as independents because they must register as Democrats or Republicans in order to participate in primary elections.
  
  

Effects

• Critics of open primaries claim these elections are vulnerable to manipulation by opposing parties. In a practice known as raiding, leaders of one party encourage their voters to vote in the opposing party's primary in order to defeat that party's strongest candidate or to otherwise influence the outcome.