easy, 9/11 doesn't happen for whatever reason. The Bush administration is plagued by links to the Enron scandal and a shaky economy. Come 2004 Howard Dean is just another DLCer, nothing special about him. John Kerry is seen as wooden and unelectable and nobody really cares that he's a veteran. Dick Gephart then emerges as a candidate that appeals to all wings of the party, he's from middle america and is a populist that will be more appealing then a guy whose main record at this point is tax cuts for the wealthy. With John Edwards as his running mate they cruise to victory.