Superdelegate

In American politics, a superdelegate is an unpledged delegate to the Democratic National Convention who is seated automatically and chooses for themselves for whom they vote. These Democratic Party superdelegates (who make up just under 15% of all convention delegates) include elected officials and party activists and officials. Democratic superdelegates are free to support any candidate for the presidential nomination. This contrasts with convention "pledged" delegates who are selected based on the party primaries and caucuses in each U.S. state, in which voters choose among candidates for the party's presidential nomination. Moreover, superdelegates are permitted to participate in the primary elections as regular voters.

At least in name, superdelegates are not involved in the Republican Party nomination process. There are delegates to the Republican National Convention who are seated automatically, but they are limited to three per state, consisting of the state chairsperson and two district-level committee members. Republican Party superdelegates are obliged to vote for their state's popular vote winner under the rules of the party branch to which they belong.

Although the term superdelegate was originally coined and created to describe a type of Democratic delegate, the term has become widely used to describe these delegates in both parties, even though it is not an official term used by either party.

Of all the delegates to the Democratic National Convention, slightly under 15% are superdelegates. According to the Pew Research Center, superdelegates are "the embodiment of the institutional Democratic Party – everyone from former presidents, congressional leaders and big-money fundraisers to mayors, labor leaders and longtime local party functionaries." For Democrats, superdelegates fall into four categories based on other positions they hold, and are formally described (in Rule 9.A) as "unpledged party leader and elected official delegates" (unpledged PLEO delegates) consisting of

...
Wikipedia