CHICAGO (CBS) — The Iowa caucuses are just three days away.

The Morning Insiders went in search of the answer to a basic question: what the heck is a caucus?

CBS 2’s Tim McNicholas hit the road to find out.

When it comes to choosing the nominees for president, more than just a river separates Iowa and Illinois.

Illinois voters know about primary elections; but in Iowa they do things a little different with caucuses.

Ellesha Gayman took CBS 2 inside the war room where she’s preparing for the Democratic Party caucus in Scott County, which includes Davenport, one of the Quad Cities along the Mississippi River.

A caucus can be described as somewhat organized chaos.

They’re held in schools, churches, convention centers, restaurants, and even living rooms.

People stand around, sometimes raising their hands, sometimes twisting arms to change the minds of their neighbors.

Here’s how it works.

People group together at a caucus site based on the candidates they support. Candidates who have at least 15% support among the caucus goers are considered viable.

If a candidate doesn’t make the cut, those supporters then get to make a second choice, and jump onto someone else’s bandwagon. If there’s more than one candidate under the 15%, their supporters can band together for one of those candidates to get them above the threshold for viability.

“It’s democracy at its very most primal state. That’s neighbors talking to neighbors, and deciding how they want to move forward,” Gayman said.

This year, for the first time, voters will fill out preference cards. On the blue side, they’ll list their first choice for the nomination; on the orange side, if needed, they’ll write their second choice.

“If there’s any close results, like we experienced with the Sanders-Clinton race in 2016, those can be actually looked at, and gone back through,” Gayman said.

Despite the new paper trail, the caucuses remain old school; informal, and unique to Iowa and a handful of other states and U.S. territories.

A ballroom at St. Ambrose University, in Davenport, will be one of the hundreds of caucus sites across Iowa.

Dr. William Parsons, head of the university’s political science department, said, as the first state in the nation to vote in the race for president, Iowa offers long-shot candidates a chance to make a name for themselves.

“If you’re an unknown candidate, spending a lot of time in Iowa – and then also in New Hampshire – which is first, it’s a way of you trying to get on the radar screen,” he said.

Compared to the secret ballots in primary elections, caucuses make voters’ choices for president very public.

“Hey, I’m going to stand up and announce my preference, basically, to the world,” Parsons said. “You may have neighbors and friends in there, and they look at you, and ‘I had no idea that this is how you were thinking.’”

Back in the war room, despite all the work, Gayman said she’s looking forward to Monday.

“Overall, it’s a good community event,” she said. “I love the caucuses.”

Tim McNicholas