Superdelegates are party officials and elected officeholders from across the country that have an individual vote at their respective party's nominating convention. They include Senators, Congresspeople, governors, former presidents and vice presidents. Other superdelegates are ordinary people who work in state and local party operations.
At the Democratic National convention almost 800 superdelegates will vote with the 3,000 pledged delegates chosen through primaries and caucuses. Because superdelegates control 40 percent of the votes needed to secure the nomination, their existence makes sure the party establishment approves of the nominee. The candidate who wins the most total delegates, committed and super, wins the nomination.
Right now both Democratic campaigns are putting enormous pressure on the superdelegates. According to party rules, the superdelegates are free to vote with their conscience, but many believe it will be undemocratic if they defy the voters' choice and bolster the candidate who did not win the majority of pledged delegates, giving him or her the nomination. Being political creatures, the superdelegates are likely to consider political factors when making their decisions.