Contested Convention

A contested convention (sometimes called a brokered convention) occurs when no presidential candidate secures an outright majority of pledged delegates during the primary season, so the party's national convention must resolve the nomination through multiple rounds of balloting and negotiation among delegates, candidates, and party leaders.

On the first ballot, most delegates are bound by primary and caucus results in their state. If that ballot fails to produce a majority, delegates are progressively released from their pledges on subsequent ballots, allowing them to switch candidates, bargain over platform planks, vice-presidential picks, or cabinet considerations, and coalesce around a consensus nominee. In the modern Democratic Party, superdelegates (party officials and elected leaders) historically could vote on the first ballot, but reforms adopted in 2018 restricted them to voting only from the second ballot onward in a contested scenario.

Genuine contested conventions were common before the McGovern–Fraser reforms of the early 1970s, which shifted nominating power decisively toward binding primaries. Notable historical examples include:

• The 1924 Democratic National Convention in New York, which required 103 ballots before nominating John W. Davis.
• The 1948 Republican National Convention, where Thomas E. Dewey secured the nomination on the third ballot.
• The 1952 Democratic National Convention, which nominated Adlai Stevenson on the third ballot.

Since 1952 no major-party convention has gone past the first ballot. Speculation about contested conventions resurfaces in crowded primary fields — for example, during the 2016 Republican race and the early 2020 Democratic race — but front-runners have consistently consolidated majorities before the convention opens.

Rules governing balloting, delegate release, and credentialing are set by each party's national committee and rules committee, meaning the procedural mechanics of any future contested convention would be defined largely by intra-party decisions made in the months immediately preceding it rather than by statute.