John Roberts will vote against DOMA&Prop 8 because he is that concerned about his legacy& the legacy of his court that he will vote against both of them. He knows that history's judgement will be on him and him alone and so he would rather have history smile on him than have it look harshly upon him...if that means Thomas,Alito&Scalia are pissed at him,that's a price he's willing to pay,I mean look at how he ruled on Obamacare.