Roberts is no judicial activist, I'll give him that.
What a disappointing week. Well, I suppose the lesson is the usual one: some of the these problems have to be solved with the ballot box, not with the courts.
Update: It's a 5-4 decision, with Chief Justice Roberts joining Justices Ginsberg, Breyer, Kagan, and Sotomayor in construing the individual mandate as a tax rather than a penalty for Constitutional purposes. (It's still treated as a "penalty" for purposes of the Anti-Injunction Act; if it had been a tax for that purpose, the Court could not have heard the case.) The Court rejected the attempt to justify the mandate as an exercise of either the Commerce Clause or the Necessary and Proper Clause, stating that the Commerce Clause cannot regulate passive non-behavior. Instead, it's simply a tax imposed on people who decline to buy insurance. The penalty is not so harsh as to constitute an absolute prohibition of the decision to go bare.
The Court struck down the portion of Obamacare that funds an expansion of Medicaid, but threatens states with the loss of all of their traditional Medicaid funding if they opt out of the expansion. As it stands, therefore, states will have a free choice whether to participate in the expanded Medicaid system.