The panicked reception in the mainstream media of the three-day Supreme Court health-care marathon is a delightful reminder of the nearly impenetrable parochialism of American liberals.

They’re so convinced of their own correctness — and so determined to believe conservatives are either a) corrupt, b) stupid or c) deluded — that they find themselves repeatedly astonished to discover conservatives are in fact capable of a) advancing and defending their own powerful arguments, b) effectively countering weak liberal arguments and c) exposing the soft underbelly of liberal self-satisfaction as they do so.

That’s what happened this week. There appears to be no question in the mind of anyone who read the transcripts or listened to the oral arguments that the conservative lawyers and justices made mincemeat out of the Obama administration’s advocates and the liberal members of the court.

This came as a startling shock to the liberals who write about the court.

Jeffrey Toobin of the New Yorker and CNN confidently asserted on Charlie Rose at the beginning of the week that the court would rule 7-2, maybe even 8-1 in favor of ObamaCare. The previous week, he called the anti-ObamaCare arguments “really weak.”

His view was echoed by an equally confident op-ed assertion by the veteran court reporter Linda Greenhouse, who in The New York Times declared the case against ObamaCare “analytically so weak that it dissolves on close inspection.”

It was quite a change, then, to see Toobin emerge almost hysterical from the Supreme Court chamber after two hours of argument on Tuesday and declare the proceedings “a train wreck for the Obama administration.”

Yesterday, after another two hours of argument, he suggested it might even be a “plane wreck.”

That was the general consensus across the board. It held that the two lawyers arguing against ObamaCare — Paul Clement and Michael Carvin — were dazzlingly effective, while the administration’s solicitor general, Donald Verrilli, put in a mediocre performance.

True enough. But here’s the thing: There was nothing new in what Clement and Carvin said.

Their arguments were featured in briefs already submitted to the court and available for general inspection. And they’d already been given weight by the two judicial opinions against the constitutionality of ObamaCare issued by federal district court judges — one by Henry Hudson in Virginia in December 2010, the other by Roger Vinson in Florida in January 2011.

The briefs exist. The decisions exist. You can Google them. They are strong, fluent, well-reasoned and legitimate. They take ObamaCare seriously, and they argue against it at the highest possible level.

Thus, the strength of the conservative arguments only came as a surprise to Toobin, Greenhouse and others because they evidently spent two years putting their fingers in their ears and singing, “La la la, I’m not listening” whenever the conservative argument was being advanced.

This is not to say that the pro-ObamaCare side had no arguments. It had plenty of arguments, and by far the most important interlocutor on its behalf was Justice Sonia Sotomayor. Her perceptive and crystal-clear questioning of Clement and Carvin should put to rest forever the idea (spread both by liberals and conservatives) that she is intellectually unworthy to serve on the nation’s highest court.

The defense of ObamaCare’s constitutionality relies mainly on the truism that everyone is sure to get sick at some point in their lives, and this makes the health-care market unlike any other market. For the liberals, this fact — bolstered by the Constitution’s Commerce Clause — gives Congress the power to compel every adult in the nation to buy a private health-insurance policy.

The attack on ObamaCare was that Congress does not have the power under the Commerce Clause to force a private citizen into a private contractual relationship. If such a thing is permitted to stand, the anti-ObamaCare forces argue, there will be no limit to Congress’s power in the future.

There’s no telling which of 10 possible ways the high court will finally rule. But one thing is for certain: There will again come a time when liberals and conservatives disagree on a fundamental intellectual matter. Conservatives will take liberals and their arguments seriously and try to find the best way to argue the other side.

And the liberals will put their fingers in their ears and sing, “La la la.”