Part of this nomination is determined by delegates, who represent the number of votes won at primaries or caucuses through the primary period. Each delegate is a representation of the popular vote for each district. It is possible to achieve more individual votes and still enter the primary with fewer delegates.

A superdelegate is something quite different and is an elected official in the Democratic Party who gets to cast an individual vote for his or her candidate of choice not based on the votes of citizens.

Up until the 1970s, party officials chose their presidential candidate. Primaries and caucuses became the principal method for giving people choice in who they wanted to run, not leaving the decision solely up to the party. But both Republicans and Democrats still wanted to have a say in the final decision, resulting in the creation of the superdelegate or unpledged delegate role. Superdelegates are chosen differently per party.

The Democrats have at present, 796 superdelegate members. These are made up of all Democratic members of Congress, Democratic governors, members of the Democratic Committee and other Democratic elected officials. In all there are a total of 4,049 superdelegates and delegates, and winning the Democratic nomination means getting 2,025 delegate votes. These numbers are subject to change and have changed from convention to convention based on a variety of factors.

Technically, a Democrat can win the nomination without any superdelegate support, but if a race is close, these votes can be extremely important.

The Republican Party has about 400 superdelegate members.