United States presidential nominating convention

A United States presidential nominating convention is a political convention held every four years in the United States by most of the political parties who will be fielding nominees in the upcoming U.S. presidential election. The formal purpose of such a convention is to select the party's nominees for popular election as President and Vice President, as well as to adopt a statement of party principles and goals known as the party platform and adopt the rules for the party's activities, including the presidential nominating process for the next election cycle. Conventions can also provide positive publicity for the nominee and party, which can then lead to a convention bounce.

Presidential nominating conventions are generally held in a different city every four years. Chicago has hosted the most major party conventions, 26, beginning with Abraham Lincoln's nomination in 1860.

The earliest public national presidential nominating Conventions have been traced back to the 1832 election, before which smaller groups of party leaders chose the nominee, arguably beginning with the 1796 election. Since 1972, most of the delegates have been selected in presidential primaries state by state. Other delegates to these conventions include political party members who are seated automatically, and are called "unpledged delegates" because they can choose for themselves for which candidate they vote. The pledged delegates determined by the primaries generally allow the nominees to be decided before the convention opens, but if no single candidate has secured a majority of both pledged and unpledged delegates then a "brokered convention" results. All pledged delegates in a brokered convention are then "released" and can switch their allegiance to a different candidate so a re-vote would result in a clear majority. Generally, use of "presidential campaign nominating convention" refers to the two major parties' quadrennial events: the Democratic and Republican National Conventions. Some minor parties also select their nominees by convention, including the Green Party, the Socialist Party USA, the Libertarian Party, the Constitution Party, and the Reform Party USA. The 2020 COVID-19 pandemic forced both the major and third parties to modify their usual conventions that year, scheduling virtual affairs with minimal participation, as large energetic crowds risked spreading the virus.