Hillary has a much higher "never voted for Democrats before" quotient with women coming out in droves for her, plus she has a never before seen Hispanic vote on her side as well as various other constituencies that are coming out for her while breaking previous records (over 55 years of age voters.)   She will have the largest share of true DEMOCRATS (a constituency Obama is seriously lacking support with.)   When Hillary wins the nomination she will start off with a tremendous coalition of Democrats, and with Obama's help (and her own appeal to young voters well established) the youth vote for her in November will truly be historic.  We have always had a huge share of the AA vote, and that will not change this time around, not with Hillary at the top of the ticket and Obama helping get his strongest demographic voting block excited about it.