What is a caucus primarily used for in the political context?

A caucus is primarily used as a meeting where members of a political party gather to select candidates or delegates for an upcoming election. This process allows party members to discuss and evaluate the potential candidates, enabling the party to present a united front in the electoral process. During a caucus, participants debate the merits of various candidates and make decisions based on the preferences expressed within the group.

Caucuses are significant in the context of electoral politics, especially in the early stages of the presidential nomination process, where they can have a substantial impact on the selection of a party's candidate. They also serve as a platform for grassroots involvement, as they allow ordinary party members to engage directly in the decision-making process.

Other options such as reforming party structures, discussing legislation, or fundraising rallies do not encapsulate the primary function of a caucus, which focuses specifically on candidate selection and delegate allocation in the context of political elections.