It takes a lot to figure out who will be the ultimate nominees to run for President. The nominees are decided state by state, either through a primary election or a caucus. But just what is a caucus?

A caucus is an open meeting, at which voters who are registered with the party discuss and debate presidential candidates. When they’re finished talking, they vote for the delegates who will back their favored candidate at the national convention.

On a state’s caucus day, these meetings are held all over the state, divided into precincts. At the end of the day… a number of delegates will emerge from each precinct who will go on to the national convention. The number of delegates from each state’s caucus are decided differently depending on the party.

Republican caucuses involve coming in, voting and dividing up delegates proportionately according to the number of votes each candidate gets. Democratic caucuses use a more complex system. Registered party members gather at precinct meeting places to discuss the candidates. Then they gather into groups according to each candidate’s support. The bigger the group, the better the chance that more of that candidate’s supporters will be represented at the national convention. Sometimes the voters need to re-group in order to gather enough support for a candidate.

Unlike primaries, which are run by state governments, caucuses are run by political parties.