1st NW Quadrant\The Approval Matrix: Week of Feb. 25, 2008
(CNN) -- Democrats say they have a "dream team" of Sens. Hillary Clinton and Barack Obama but they might be looking at a nightmare if superdelegates have to determine which one will be at the top of the ticket.
Usually the superdelegates are an afterthought -- the nominee normally emerges before the National Democratic Convention by winning enough delegates in the caucuses and primaries to capture the nomination.
But this year, Obama and Clinton are running such a tight race that after millions of votes and months of campaigning, neither candidate is expected to have the 2,025 delegates needed to seal the nomination before the August convention.
And the superdelegates, a group of about 800 people who cast their vote at the convention, could set a candidate over the top.
Superdelegates -- made up of governors, senators, house members and various other other party officials or members -- are also known as "unpledged" delegates.
They are free to choose the candidate they like, while pledged delegates are assigned in primaries and caucuses.
Many superdelegates pledge allegiance to a candidate well before the party convention, but they can change their minds. Superdelegates make up around 20 percent of the total delegates.