A primary is a preliminary election held by a political party before the actual election, to determine its candidates. A primary may be open or closed. An open primary is one in which all registered voters may participate. The number of delegates a candidate receives is then based on the candidate's performance. In some states, the winner of the popular vote wins all the delegates available to the state at the nominating convention. In other states, candidates receive a portion of delegates based on their respective showings.

In a closed primary, only voters who have declared their allegiance to the party may vote. Closed primaries may be indirect or direct. In an indirect, closed primary, party voters only elect delegates who later vote for the party's candidates at a nominating convention. In a direct, closed primary, party voters actually decide who will be the party's candidates, and then choose delegates only to communicate that decision at the nominating convention.

In some states (e.g., Iowa), political parties use a caucus system, instead of a primary system, to determine which candidates to support. A caucus is a local meeting of registered party members. The manner in which delegates are chosen at these caucuses varies widely from state to state. In some states, each party member who attends the caucus is entitled to one vote for each office. The caucus then produces an allotment of delegates based on the popular vote in the caucus, and these delegates later represent the caucus in the county, legislative district, state, and national conventions. In other states, those who attend the caucus vote for delegates who pledge their support for certain candidates. These delegates then represent the caucus at the party's nominating conventions.

Source Citation: "Elections." West's Encyclopedia of American Law. Eds. Jeffrey Lehman and Shirelle Phelps. Vol. 4. 2nd ed. Detroit: Gale, 2005. 6 pp. 13 vols. Gale Virtual Reference Library. Gale.