Reportedly, the bottom line in the opinion upholding the individual mandate is this: “Our precedent demonstrates that Congress had the power to impose the exaction in Section 5000A under the taxing power, and that Section 5000A need not be read to do more than impose a tax. This is sufficient to sustain it.”
Apparently, then, in the view of the majority this turns out not to be a Commerce Clause case after all. A majority found that the individual mandate violates the Commerce Clause, but it still survives.
Justice Kennedy wrote the dissent. He, along with Justices Scalia, Thomas, and Alito, would have struck down the entire Act. Thus, the always unpredictable Kennedy came through; the newly unpredictable Roberts did not.