How the Iowa Caucuses Work, Step by Step

To people accustomed to voting in primaries by walking into a polling site, privately completing a ballot and walking out — which is to say, most of the country — caucuses may seem bewildering.

They certainly did to Mary Doyle when she went to her first caucus more than 20 years ago, after moving to Iowa from Illinois. “I had no clue what was going on,” she said. “It was all brand-new. These people get up and talk, and everybody’s talking, and I didn’t know anybody.”

Like many Iowans, Ms. Doyle — who will be a precinct captain for former President Donald J. Trump at a caucus site in western Des Moines on Monday night — came to love the caucus process, with its open expression of candidate preferences and attempts at last-minute persuasion.

Caucuses also have their critics, who note that the process makes voting inaccessible for some people and tends to lead to lower turnout than primaries.

But love them or hate them, they are still happening. At 7 p.m. Central time, caucusgoers will gather — if they are not deterred by the bitter cold — in schools, community centers and other sites across the state.

Here is a step-by-step guide to how the caucuses will work.

Arrival

Voters will arrive at their designated caucus site and sign in. Workers will check each person’s ID and voter registration. While only registered Republicans can participate, people are allowed to register or change their party affiliation on the spot.

If the campaigns are well organized, each candidate will have a captain on site at each precinct, and that captain may hand out stickers, hats or other swag to supporters as they arrive — a sort of visual display of the strength of that candidate’s support.

Mingling

As people wait for the caucus to formally begin, caucusgoers can talk among themselves. Especially in small communities, many of them will know each other, and many of them will start discussing their candidate preferences. They may try to persuade one another if they see an opening.

Cody Hoefert, a precinct captain in Rock Rapids for Ron DeSantis who has served as a captain in many election cycles and is a former co-chairman of the Iowa Republican Party, said he would be striking up conversations, looking for people who were undecided or not firmly committed to their choice, and giving them his pitch for Mr. DeSantis.

Proceedings begin

The caucus will be called to order, and the caucusgoers’ first order of official business will be to elect a chair to oversee the proceedings.

Speeches

A representative for each candidate — generally, precinct captains chosen in advance by the campaigns — will have a chance to give a short speech. Time restrictions can vary from site to site, generally from two to five minutes.

This is the part of the process that most distinguishes caucuses from primaries: Participants are, up until the very last moment, actively trying to recruit more people to their side. While most voters are likely to have made up their minds, some may wait to make a final decision until they hear the speeches, and — you never know — some may be leaning toward one candidate but be swayed by a particularly persuasive speech.

Voting

Paper ballots will be distributed, and people will cast their votes.

The votes will be counted on-site right away. The captains will observe the counting process and flag any problems that they see, and regular caucusgoers are allowed to watch as well. The results will be announced out loud and then sent to the state party.

The state party will tabulate results from all the precincts and release the statewide totals to the public.