Even the Republicans themselves have acknowledged they have a diversity problem. If you look at their autopsy report following the 2012 election, they have specifically said they would continue to lose presidential elections unless they address the problem that they have with their alienation of minority groups.

We are, as a Democratic Party, really highlight and emphasize inclusiveness and diversity at our convention, and so we want to give every opportunity to grass-roots activists and diverse committed Democrats to be able to participate, attend, and be a delegate at the convention.

Unpledged delegates exist really to make sure that party leaders and elected officials don't have to be in a position where they are running against grassroots activists.

Debbie Wasserman Schultz Quotes