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A Project of The Annenberg Public Policy Center

Caucus vs. Primary

Q: What is the difference between a caucus and a primary?

A: In presidential campaigns, a caucus is a system of local gatherings where voters decide which candidate to support and select delegates for nominating conventions. A primary is a statewide voting process in which voters cast secret ballots for their preferred candidates.


Caucuses were once the most common way of choosing presidential nominees. In 2020, only five states — Iowa, Kentucky, Nevada, North Dakota and Wyoming — are set to have either a Democratic or Republican caucus, according to the National Conference of State Legislatures. (The Hawaii Republican Party had been scheduled to have a caucus but canceled it and committed its delegates to Trump.) And four U.S. territories — American Samoa, Guam, Northern Mariana Islands and the Virgin Islands — will also hold either Democratic or Republican caucuses, according to the Federal Election Commission.

Caucus meetings are arranged by either the state or political party to take place at a certain place and time. Caucuses are unique in that they allow participants to openly show support for candidates. Voting is often done by raising hands or breaking into groups according to the candidate participants support. The results of the caucus are used to determine the delegates present at county, state and national nominating conventions of each political party. Most often, only registered voters can participate in a caucus, and they are limited to the caucus of the party with which they are affiliated.

Primaries are a direct, statewide process of selecting candidates and delegates. Similar to the general election process, primary voters cast secret ballots for the candidates of their choosing. The results are used to determine the configuration of delegates at the national convention of each party. Primaries come in two basic forms: In an open primary, all registered voters can vote for any candidate, regardless of their political affiliation. Registered Democrats may vote for a Republican candidate, and Republican voters may cast ballots for a Democrat, for instance. And registered Independents can participate in either party’s primary. But in a closed primary, voters may vote only for candidates of the party with which they are registered.

Update, Feb. 3, 2020: We have updated this item to note the states and territories that will have either a Democratic or Republican caucus during the 2020 election cycle.

– D’Angelo Gore


U.S. Department of State. “Glossary.” America.gov, 9 Oct. 2007

Project Vote Smart. “How does the primary process work?” Accessed 4 April 2008

Federal Election Commission. “2008 Presidential Primary Dates and Candidate Filing Deadlines for Ballot Access.” 28 March 2007, Accessed 4 April 2008