When Democrats attend a caucus, they break into groups that publicly declare their support for a candidate. If the number of people in any group is fewer than 15 percent of the total, they can either choose not to participate or can join another candidate group. That leads to some intense wooing and sometimes confusion as candidate representatives try to persuade others to join them and prevent their supporters from switching to another top candidate.

The results are the first step in determining delegates who are expected to support candidates at the national convention. A total of 44 delegates to the national convention are at stake. They will be awarded proportionally, based on the statewide vote as well as on the vote in individual congressional districts, to candidates who get at least 15 percent of the vote.