open primary

A primary election is a preliminary election in the United States where voters select candidates to run for public office. There are two main types: closed primaries, where only declared party members can vote, and open primaries, where any voter can choose which party's primary to participate in without declaring affiliation.123

Primaries can also be direct or indirect. In a direct primary, voters directly choose their party's candidates. In an indirect primary, voters elect delegates who then select the party's nominees at a convention. The direct primary system, largely a product of the Progressive movement, became widespread in the early 20th century. Rules for primaries, including delegate selection for presidential elections, vary by state and political party.14