Primary elections differ from general elections in the United States as they are held to determine the candidates that political parties will nominate for the general election. In primary elections, voters select a party's nominee, which can be either closed, allowing only registered party members to vote, or open, permitting voters to choose candidates from any party. General elections, however, are for choosing public officials from among the nominated candidates. This distinction is crucial as primary elections can significantly shape party platforms and influence campaign strategies for the general election.