One thought I had listening to Roberts and his answers is, "Can this man possibly be a persuasive force with the other justices who vote liberal?" In other words, can this man by more than his single vote on the bench, exert enough influence and persuasiveness that will move the other more liberal justices? Thomas and Scalia I am not worried about.
I am sure he will, especially since he is going to fight tooth and nail against the likes of Justices Kennedy and Breyer who insist on using foreign law to interpret the Constitution.