Electoral device for choosing a party's candidates for public office.
The formal primary system is peculiar to the U.S., where it came into widespread use in the early 20th century. Most U.S. states use it for elections to statewide offices and to the national presidency; in presidential elections, delegates are selected to attend a national convention, where they vote for the candidate to whom they are pledged. A closed-vote primary is restricted to party members; an open-vote primary is open to all voters in the district. Names can be placed on a ballot by an eligible citizen's declaration of candidacy, by nomination at a pre-primary convention, or by a petition signed by a required number of voters. In the late 20th and early 21st centuries political parties in some countries (e.g., the United Kingdom and Israel) adopted similar procedures for the election of the national party leader. See also electoral system ; party system .