The U.S. presidential primaries are a series of elections held by political parties to select their candidates for the presidency. These primaries occur in each state and can be either open or closed, meaning that registered party members may or may not allow unaffiliated voters to participate. The results help determine how many delegates each candidate will receive for the party's national convention. During the national convention, delegates officially nominate the party's candidate, who will then run in the general election against candidates from other parties. The primaries are crucial for shaping the political landscape and influencing voter preferences leading up to the election.