There were a few interesting features of today's decision that begin to sketch the contours of the court's Roberts era. If Alito was already on the bench the vote count would have been 5-4 making Kennedy the central swing vote in this decision. Dahlia Lithwick in Slate paints a convincing picture of Kennedy's critical position at the center of this court.
Despite Roberts' vote in this case (joining Scalia's dissent) his views on federalism remain unknown. Is he likely to follow Rehnquist's lead by more often seeming to set limits on congressional authority or will his commitment to federalism principles be more selective like Scalia? Ann Althouse makes some interesting points about the case on her blog.
"It's quite interesting that the majority is made up of everyone who voted in favor of congressional power in the medicial marijuana case, plus O'Connor and minus Scalia. That means only O'Connor took the strong federalism position in both cases. And only Scalia sided with the government in both cases"