My perception of John Roberts: he's a career washington insider that is totally political but he desperately wants to appear non-political. So he calculatedly makes some ruling in things where it surprises people but then twists his mind into unbelievable pretzel knots to justify positions on others so he can rule in favor of something he politically desires while trying to appear as if he is just following the law (which doesn't work).
In his zeal to trick people into believing that he's not political he actually has become MORE political than he probably was before. Nobody can possible believe at this point that the man rules solely on the basis of the constitution at this point, not since Obamacare and several other eye popping positiobs he's taken.