I think Obama would benefit more from a sitting governor as his VP candidate. But his camp may view an endorsement from Edwards as being worth it. I think a Clinton-McCain matchup would go to McCain, but it's a bit cloudier if it's Obama-McCain. It's hard to say that the GOP base would be as energized against Obama. Given the base's lukewarm to antagonistic view of McCain, if you have a non-Clinton opponent who's not that all unlikable and who has appeal to moderates and independents, many of them could stay home.