National Party Conventions

Early presidential candidates were chosen by party members in Congress, a system called King Caucus. The Anti-Masonic Party held the first national nominating convention in Baltimore in September 1831, and the Democrats and National Republicans soon followed. For more than a century, conventions were where nominations were actually decided, often after many ballots and back-room bargaining: the 1924 Democratic convention needed 103 ballots. Conventions also wrote party platforms and chose vice presidential nominees.

Since the reforms of the 1970s, most delegates are chosen in primaries and caucuses and pledged to candidates, so the nominee is usually known months before the convention, which has become a formal ratification and a televised showcase. Democratic delegates include elected officials and party leaders known as superdelegates, who since 2018 may not vote on the first ballot unless the outcome is already decided. Each party's rules committee, platform committee, and credentials committee meet before the convention, and the nominee's acceptance speech is the climax of the event. The last convention to need more than one ballot was the Democratic convention of 1952.

Conventions can still matter when a nomination is contested or a candidate withdraws. In 2024, after President Joe Biden ended his campaign on July 21, Democrats nominated Vice President Kamala Harris through a virtual roll call of delegates in early August, before the convention in Chicago, while Republicans met in Milwaukee in July. Supporters say conventions unify parties and introduce nominees to voters, while critics say they have become costly infomercials, and some have proposed that parties restore conventions as a real deliberative check on nominees.