One of the striking things about Roger Vinson's ruling striking down the Affordable Care Act -- which I appraise rather critically in my latest TRB column -- is that there are three distinct legal rationales for the law, and Vinson's ruling finds a way to reject all three of them. One rationale is Congress's authority to tax, which Vinson rejects by deciding the penalty on people who go without health insurance is not a tax. The second is the Commerce Clause, which he rules out by concocting a distinction between activity and "inactivity," the latter of which he claims Congress can't regulate.
And then the third is the Necessary and Proper clause. The Constitution gives Congress authority to enact any laws necessary and proper to execute its others enumerated powers. Charles Fried notes that conservatives on the Supreme Court have previously interpreted this clause, sensibly, to allow Congress to carry out its authority as the clause reads:
Fried supported Roberts and Alito as well and said in an interview he does not believe either of them would be inclined toward "such a departure from standard Commerce Clause jurisprudence."
He added, "I don't see Roberts as going for this tea party stuff."
Fried pointed, as others have, to a case from last term. The chief justice, in U.S. v. Comstock, agreed that the Necessary and Proper Clause gave the government the right to to detain sexually dangerous federal prisoners even after their sentences were completed, although even the power to imprison is not explicit in the Constitution.
Roberts assigned the ruling to Breyer and joined the broadly written opinion in full, something neither Kennedy nor Alito was willing to do, even though both agreed with the outcome.
I think it's obvious that any ruling based on legal precedent will uphold the Affordable Care Act, and not by a 5-4 margin. Keep in mind that striking down the law is a kind of inside straight that requires 5 justices to each reject all three possible legal rationales for the individual mandate, and each rationale has a fairly strong basis in precedent. The only question is whether the justices will follow precedent or just decide to strike down a law they don't like.