To what extent did SCOTUS inhibit Congress's power to regulate commerce?

Yesterday, I suggested that the Supreme Court's finding that the individual mandate exceeded Congress's Commerce Clause powers did not in fact crimp Congress's ability to regulate commerce in any significant way, since Congress has no desire to impose any more purchase mandates. Donald Verrilli stressed in his reply brief that health insurance is a unique case, pointing out that states, which have an unquestioned power to impose purchase mandates, don't do it. Justice Ginsburg made the same point in exquisite detail in her dissent with regard to the Commerce Clause.

In today's Times, however, Neal Katyal, who served as acting Solicitor General after Obama appointed Elena Kagan to the Supreme Court and who argued the ACA case at the appellate level, makes a compelling case that the decision did limit the federal government's power and expand the Court's propensity to legislate from the bench in significant ways. Chief among them was in its invalidation of Congress's power to enforce its expanded Medicaid mandate:

until now, it had been understood that when the federal government gave money to a state in exchange for the state’s doing something, the federal government was free to do so as long as a reasonable relationship existed between the federal funds and the act the federal government wanted the state to perform.

In potentially ominous language, the decision says, for the first time, that such a threat is coercive and that the states cannot be penalized for not expanding their Medicaid coverage after receiving funds. And it does so in the context of Medicaid, which Congress created and can alter, amend or abolish at any time. The states knew the terms of the deal when they joined — and those terms continue to be enshrined in the federal code. 

This was the first significant loss for the federal government’s spending power in decades. The fancy footwork that the court employed to view the act as coercive could come back in later cases to haunt the federal government. Many programs are built on the government’s spending power, and the existence of an extraconstitutional limit on that power is a worrisome development.

With regard to Roberts' finding "that the individual mandate is not a valid exercise of Congress’s power under the Commerce Clause and the Necessary and Proper Clause," I believe it's true that the particulars of that ruling won't matter to Congress, since no one is inclined to impose further mandates -- or would be, even if the Court ruled 9-0 that the mandate was Constitutional under the Commerce Clause. But Katyal points to a broader inhibiting principle (my emphasis):

While the court upheld the mandate, it did so by rejecting the federal government’s claim that it was regulating commerce. There is no judicial precedent or language in the Constitution that compelled that result; instead, the majority reasoned by constitutional inference. 

The court employed language that could be read to suggest that whenever statutes are novel, they are unconstitutional. This atextual reading of the Constitution, odd for “strict constructionists,” may later blossom into a radical constitutional theory that could upend decades, if not centuries, of precedent, going all the way back to Chief Justice John Marshall’s famous opinion in the 1819 case McCulloch v. Maryland, which spoke of a flexible, adaptable Constitution.

The question of whether Congress can come up with new tools to deal with new problems is a core issue, argued in detail in the briefs and in oral argument.  Verrilli's reply brief makes an historical argument that Congress had to repeatedly devise new means of  regulating commerce as the modern industrial economy emerged, concluding:

Indeed, "in almost every instance of the exercise of the[commerce] power" during the modern era, "differences [were] asserted from previous exercises of it and made a ground of attack." Hoke & Economides v. United States, 227 U.S. 308, 320 (1913).  But the Court has not invalidated laws simply because Congress chose to address a worsening national economic problem with new regulatory tools that Congress concluded were well adapted to addressing it (p. 17).

Roberts' decision effectively retorts, "it's not any novelty we've set our face against. It's your novelty" (as Chuck Berry claimed his Baptist minister father told him, "Son, there's nothing wrong with sex. It's just the way that you handle it"). Roberts acknowledges: "Legislative novelty is not necessarily fatal; there is a first time for everything" (p. 12). He then goes on, however, to accept the plaintiffs' activity vs. inactivity distinction: "Construing the Commerce Clause to permit Congress to regulate individuals precisely because they are doing nothing would open a new and potentially vast domain to congressional authority" (p. 20).

Hence Roberts puts a limiting principle on his limitation of the Commerce Clause: he rules simply that Congress cannot "create" commerce. That should not in itself concern progressives. The government's reply brief asserts that there's no reason to assume that Congress, if green-lighted here, will gleefully go on to enact a series of absurd purchase mandates. The brief cites New York v. United States, which found that the "process of Constitutional adjudication does not thrive on conjuring up horrible possibilities that never happen in the real world and devising doctrines sufficiently comprehensive in detail to cover the remotest possibility."  Justice Ginsburg's dissenting opinion is on point and hilarious in dissecting the unlikelihood of the "broccoli horrible" and other potential purchase mandates conjured up by the plaintiffs.

Is the Court in the process radically inhibiting Congress's power to act?  Narrowly divided as the Court is, the answer probably depends on which party gets to make the next several appointments.  Or, given the new heights (or depths) to which Republicans have taken obstruction in the Obama years, on the lengths to which the GOP is willing to go to stymie and ultimately shape Obama's next appointments, should he win in November.

UPDATE: Randy Barnett, chief architect of the case against the mandate, takes a victory-manque lap:

“Congress can’t do whatever it wants,” he said. “Under this ruling, Congress can’t put you in jail for violating a future economic mandate. This holding stands for that proposition. Congress also can’t coerce states by withholding all existing Medicaid funding unless they agree to new coverage. That’s a constraint the Court has never enforced before. And the Necessary and Proper Clause cannot be used to salvage these laws. And that’s a ruling we haven’t had before.”

 Congratulations -- for ensuring that Congress can't do what Congress will never want to do.