Chief Justice John Roberts agreed with the conservatives that the Commerce Clause and the Necessary and Proper Clause are not a sufficient foundation for the individual mandate in the universal healthcare law. He agreed with the liberals, though, that the mandate could stand, because it is not really a mandate but an exercise of Congress' taxing power.
Some see this as an incoherent position, or some kind of sellout. I disagree. I think the Chief Justice has forged an important centrist position.
In fact, I think he may be finding his way to be the leader of the middle of the court, so that the Supreme Court is more than just a battle of left vs. right. He has said that he wants to see - to create - more unanimous decisions, and fewer of the horrible 5-4 slugfests that we have seen in recent years. I wish him very well in that quest.