Primaries and caucuses are methods used by political parties in the United States to select their nominees for various offices, especially for presidential elections. Primaries are state-level elections where party members cast votes for their preferred candidate, while caucuses are local gatherings where voters discuss and then vote for candidates. Primaries can be closed, open, or semi-closed, influencing who can participate. Caucuses tend to involve more extensive discussion and debate, fostering engagement among party members. Both processes are critical for shaping the party's electoral strategy and ultimately determining its candidate in the general election.