What’s the difference between a caucus and a primary?

Modern Caucuses and Primaries

The caucus process hasn't changed much at all since each party began nominating their choices for president at their national conventions in the early 19th century. In Iowa, for example, voters in each local precinct (there are around 1,700) gather in gyms, bars and basements to openly discuss the presidential election, not just vote for a specific candidate [source: Praetorius]. Supporters give impassioned speeches on behalf of their candidate, attempting to sway the undecided folks in the room. Unlike primaries, caucuses are held at a specific time of the day, the only time when voters can cast their ballot. In fact, there don't even have to be official ballots. Local caucus organizers can simply call for a show of hands, or ask folks to divide into groups according to their candidate.

It's important to note that the results of local caucuses don't directly influence the proportion of delegates sent by each party to the national convention. Instead, delegates are chosen through a multi-stage, months-long process. In Iowa, for example, the precinct caucuses help to portion out delegates for the county conventions, which help to choose delegates for the district conventions, which vote to choose delegates for the state convention, which finally chooses the delegate distribution for the national convention. To further confuse matters, the Republican and Democratic Iowa caucuses each have different rules governing the distribution of delegates and whether or not votes cast in each stage of the process are even binding!

Several states hold both a primary and caucuses, although only one of the contests results in the selection of delegates. Non-binding caucuses and primaries are sometimes called straw polls, or the more colorful term, "beauty contests" [source: Seelye]. Most states opt for primaries with only Alaska, Colorado, Hawaii, Iowa, Kansas, Maine, Minnesota, Nevada, North Dakota and Wyoming relying solely on caucuses [source: FactCheck].

For lots more information about U.S. elections and political controversies, explore the related links below.

Author's Note

Our mission as HowStuffWorks writers is to explain complicated things in uncomplicated ways. Often the topic is something highly technical, like the Internet or electric cars. And sometimes, like today's assignment, it's perversely political. The caucus process is one of those subjects that defies a simple answer. Each state that organizes a caucus does so under its own arcane rules and archaic methods. Supporters of the caucus system argue that the super-local nature of the caucus is one of the last bastions of grassroots politics. Critics say that the eccentricities of the caucus system effectively exclude all but the most "activist" voters, resulting in a skewed selection process. I say, scrap both caucuses and primaries and bring on the cage fighting.

Related Articles


  • PBS NewsHour. "The Primary versus the Caucus." December 15, 2003 (April 24, 2012) http://www.pbs.org/newshour/vote2004/primaries/sr_primary_caucus.html
  • Praetorius, Dean. The Huffington Post. "What Is a Caucus? How the Iowa Caucus Works." January 3, 2012 (April 24, 2012) http://www.huffingtonpost.com/2012/01/03/what-is-a-caucus-iowa-2012_n_1181069.html
  • Redlawski, David P.; Tolbert, Caroline J.; and Donovan, Todd. Why Iowa? Why Caucuses and Sequential Elections Improve the Presidential Nominating Process. "Iowa Caucus Rules." University of Chicago, 2011. http://www.whyiowa.org/Why Iowa Chapter 3.pdf
  • Seelye, Katherine Q. The New York Times. "Romney's Victory in the Maine Caucuses Is at Risk." February 16, 2012 (April 23, 2012) http://thecaucus.blogs.nytimes.com/2012/02/16/romneys-victory-in-the-maine-caucuses-is-at-risk/
  • The Takeaway. "What's the Difference Between a Caucus and a Primary?" February 7, 2012 (April 22, 2012) http://www.thetakeaway.org/2012/feb/07/whats-difference-between-caucus-and-primary/
  • Washington State Democrats. "2012 Caucuses and Conventions" (April 24, 2012) http://www.wa-democrats.org/caucuses