This is why they are taking so long to pick a VP. Campaign sources said today that the decision probably won't be announced this coming week. The last few names they have run up the flag have fallen flat. Rice's name was met by party brass with absolute horror, feeling that Bengazi along with some of her public statements would be a huge minus.
Whether or not they actually run Biden, they apparently think that the VP will at some point assume the Presidency either as the actual nominee or at some point during the term.