According to the University of Washington’s Civic Engagement Center, a national convention for a political party is an event in which members set the party platform and nominate a presidential candidate and vice-presidential candidate. Each political party has an individual national convention. Delegates from each state attend the convention to cast a vote for a candidate and for policies that the party espouses.
Some state parties require that delegates vote in the same manner as the outcome of the primary or caucus; however, not all state parties have this requirement. Typically, the members of a party already vote for the presidential nominee during the primary season, and the vote at the national convention is a ceremonial, however official, mark for the winner. If there is a rare tie during the primary election, the delegates at the convention choose the nominees by a specific set of rules for each party. Delegates also submit and vote on official stances for the party to take in the upcoming year.
The two most popular American political parties, Democratic Party and Republican Party, use national guidelines for the proper nomination of candidates at the convention. Smaller parties, also known as third parties, abide by a specific nomination process that varies by each state.