Final answer:
In a closed primary, only registered party members can vote in their party's selection process. This method ensures the party's candidates are chosen by those with genuine party affiliations and helps to prevent voters from outside the party from influencing the selection of its nominees.
Step-by-step explanation:
In a closed primary, only voters who are registered as members of a political party can participate in the selection process for that party's candidates.
This system is utilized to ensure that the candidate nominated for a party's ticket is chosen by voters who are legitimately affiliated with that party, as opposed to an open primary system where any registered voter can participate in the party's primary, irrespective of their party affiliation. The closed primary is one of several types of primaries used in the United States, including open, semi-closed, and semi-open primaries, each with rules on who is permitted to participate in a party's primary election.