Back in 2010, Georgetown Law professor Randy Barnett, who has been described as the legal architect behind challenges to the health care law, wrote a paper on the unconstitutionality of Obamacare in which he issued the following warning about the Obama administration’s taxing power claim:

“(T)he government’s tax power theory is far more radical than the Commerce and Necessary and Proper Clause theory precisely because the Supreme Court has generally deferred to any invocation of the tax power to raise revenue to spend for the general welfare. This normal deference is why the mandate’s defenders shifted the argument from the Commerce Clause to the tax power. Yet if its theory is accepted, Congress would be able to penalize or mandate any activity by anyone in the country, provided it limited the sanction to a fine enforced by the Internal Revenue Service. This is a congressional power unknown and unheard of before 2010. It would effectively grant Congress a general police power. And we know what existing doctrine says about such a power: ‘The Constitution . . . withhold[s] from Congress a plenary police power that would authorize enactment of every type of legislation.’ Such has been the Supreme Court’s position from the Founding until today.”

Yet in the wake of the Chief Justice John Roberts’ majority decision to uphold the mandate on taxing power grounds, Barnett has been downplaying the legal significance of that precedent, especially relative to the Court’s ruling that the law was not allowable under the Commerce Clause. This morning I asked him why his views had changed on the dangers of the taxing power since he wrote the paper.

“Chief Justice Roberts rewrote the (health care) statute to change this from a requirement, or mandate, to an option to buy insurance or pay a penalty,” Barnett explained. “This is far less dangerous than had the mandate been upheld under the commerce power. Because a Commerce Clause regulation could be upheld up to and including imprisonment as drug laws are, but this power is limited to paying a tax (for those who pay taxes) and can be as politically toxic as taxes are.”

I asked him whether a future Congress could just repeat what we saw in this instance – call a mandate a penalty for the purposes of passing the bill, then switch around and call it a tax in court.

“That is never going to happen again,” he insisted. “No one is ever going to fall for that again…The findings in the (health care) bill were Commerce Clause. The findings in the next bill will have to be taxing power.”

In other words, future Congresses would have to explicitly use taxing power justifications for any future economic mandates.

He predicted, “We have years before any future Congress is going to work up the nerve to do anything like a broccoli mandate. If we don’t change the political and legal culture between now and then, broccoli mandates are going to be the least of our worries.”

Despite the adverse policy outcome for supporters of limited government, Barnett said the decision advanced the legal cause for limited government.

“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.”

He continued, “This is big. And it’s only the stinging disappointment of not being able to take down Obamacare that conceals how big this was. Every one of our arguments got accepted by five justices. Every one.”

Now that the legal battle over the mandate is over, he said it will have to be up to the people to repeal the law through the electoral process.

“I always thought, these two rows rose and fell together — if we lost Obamacare, we’d lose the Constitution, and if we won on the Constitution, we’d win on Obamacare,” he said. “But if you ask me what I’d rather pick in court, which one I would win on, I’d pick winning on the Constitution and losing Obamacare, because the people can beat Obamacare, but if we had lost in court on the Constitution, it would take a generation of elections to get the Constitution back.”

Barnett criticized Roberts’ reasoning in upholding the mandate on taxing grounds, but said it was too flimsy to survive as constitutional doctrine.

“It’s lame,” he said. “The reasoning is transparently lame, and that doesn’t hurt, that helps. Transparently lame reasoning doesn’t stand the test of time. What will stand the test of time is everything he had to say about the Commerce Clause and Necessary and Proper Clause, because that was hard-edged. And that had five votes in support of it.”

In his opinion, Roberts compared the mandate to a cigarette tax. But in that case, Congress is imposing a tax to discourage a behavior. Thursday’s ruling broadened the taxing power to enable Congress to impose a penalty on somebody for not engaging in a behavior.

“That is an expansion of the use of the tax power beyond where it’s gone before,” Barnett said. “(Roberts) claimed it wasn’t, that’s lame too. It’s an expansion. It’s just an expansion that Congress will not make use of in the near future and a future court can fix and so what’s necessary now is political action to ensure that that’s not a problem.”

He explained, “If we do change the legal culture, even in the slightest, and we do get new justices on the Court, they are not going to have any problem with this precedent on the tax power. It was lame, it was (Roberts’) own opinion, it built in trip wires that could easily be used in the future by a court that cared. This tax thing is easily fixed. A Commerce Clause ruling that Congress had unlimited discretion to pick whatever means are necessary to effectuate its Commerce Clause powers, see McCullouch v. Maryland, we would never get that undone. This was huge.”

I asked Barnett to respond to the fact that in the broader sense, the Supreme Court still advanced the assumption that it would find some way of justifying Congressional action when it comes to major legislation.

“Four justices weren’t prepared to do that, one was,” Barnett said. “We had to hold all five. We start off with four against us, we knew that. Every time we have to hold all five. Here’s what it tells you – five justices are not enough. That’s your lesson…You need seven. If we have seven justices, Congress won’t mess with this. With five justices, sure.”

On the other hand he said, “This case reaffirms everything we said about constitutionally limited government. Everything that the other side has said was frivolous has been affirmed by the Court. It is now the law. It will be taught in every constitutional law class. You think anybody is going to spend time teaching this tax power argument in con law class?”