By PAUL KRUGMAN – New York Times.

Nobody knows what the Supreme Court will decide with regard to the Affordable Care Act. But, after this week’s hearings, it seems quite possible that the court will strike down the “mandate” — the requirement that individuals purchase health insurance — and maybe the whole law. Removing the mandate would make the law much less workable, while striking down the whole thing would mean denying health coverage to 30 million or more Americans.

Given the stakes, one might have expected all the court’s members to be very careful in speaking about both health care realities and legal precedents. In reality, however, the second day of hearings suggested that the justices most hostile to the law don’t understand, or choose not to understand, how insurance works. And the third day was, in a way, even worse, as antireform justices appeared to embrace any argument, no matter how flimsy, that they could use to kill reform.

Let’s start with the already famous exchange in which Justice Antonin Scalia compared the purchase of health insurance to the purchase of broccoli, with the implication that if the government can compel you to do the former, it can also compel you to do the latter. That comparison horrified health care experts all across America because health insurance is nothing like broccoli.

Why? When people choose not to buy broccoli, they don’t make broccoli unavailable to those who want it. But when people don’t buy health insurance until they get sick — which is what happens in the absence of a mandate — the resulting worsening of the risk pool makes insurance more expensive, and often unaffordable, for those who remain. As a result, unregulated health insurance basically doesn’t work, and never has.

There are at least two ways to address this reality — which is, by the way, very much an issue involving interstate commerce, and hence a valid federal concern. One is to tax everyone — healthy and sick alike — and use the money raised to provide health coverage. That’s what Medicare and Medicaid do. The other is to require that everyone buy insurance, while aiding those for whom this is a financial hardship.

Are these fundamentally different approaches? Is requiring that people pay a tax that finances health coverage O.K., while requiring that they purchase insurance is unconstitutional? It’s hard to see why — and it’s not just those of us without legal training who find the distinction strange. Here’s what Charles Fried — who was Ronald Reagan’s solicitor general — said in a recent interview with The Washington Post: “I’ve never understood why regulating by making people go buy something is somehow more intrusive than regulating by making them pay taxes and then giving it to them.”

Indeed, conservatives used to like the idea of required purchases as an alternative to taxes, which is why the idea for the mandate originally came not from liberals but from the ultra-conservative Heritage Foundation. (By the way, another pet conservative project — private accounts to replace Social Security — relies on, yes, mandatory contributions from individuals.)

So has there been a real change in legal thinking here? Mr. Fried thinks that it’s just politics — and other discussions in the hearings strongly support that perception.

I was struck, in particular, by the argument over whether requiring that state governments participate in an expansion of Medicaid — an expansion, by the way, for which they would foot only a small fraction of the bill — constituted unacceptable “coercion.” One would have thought that this claim was self-evidently absurd. After all, states are free to opt out of Medicaid if they choose; Medicaid’s “coercive” power comes only from the fact that the federal government provides aid to states that are willing to follow the program’s guidelines. If you offer to give me a lot of money, but only if I perform certain tasks, is that servitude?

Yet several of the conservative justices seemed to defend the proposition that a federally funded expansion of a program in which states choose to participate because they receive federal aid represents an abuse of power, merely because states have become dependent on that aid. Justice Sonia Sotomayor seemed boggled by this claim: “We’re going to say to the federal government, the bigger the problem, the less your powers are. Because once you give that much money, you can’t structure the program the way you want.” And she was right: It’s a claim that makes no sense — not unless your goal is to kill health reform using any argument at hand.

As I said, we don’t know how this will go. But it’s hard not to feel a sense of foreboding — and to worry that the nation’s already badly damaged faith in the Supreme Court’s ability to stand above politics is about to take another severe hit.