Linda Greenhouse is something of an institution of legal journalism. She became the New York Times’s Supreme Court correspondent in 1978. Thirty years later, when she accepted an early-retirement package from the financially stressed newspaper, Legal Times reported that a 7–2 majority of the justices threw a going-away party for her, “complete with cheese, desserts, and prosecco wine.” She is also the namesake of the Greenhouse Effect, the hypothesis that “swing” justices like Anthony Kennedy trended leftward in the hopes of garnering positive coverage from her.

Greenhouse still writes for the Times, only she’s moved to the editorial page’s “Opinionator” blog. The week before the high court heard oral arguments about Obamacare’s constitutionality, she weighed in with a revealing post. She began with a close examination of her own venerable navel:

Journalistic convention requires that when there are two identifiable sides to a story, each side gets its say, in neutral fashion, without the writer’s thumb on the scale.… Court cases are trickier. It’s one thing to engage in prediction that flows from analysis: which side is most likely to win? It’s quite another to let readers in on the fact that one side’s argument is so manifestly weak that it doesn’t deserve to win.

The way to do what Greenhouse wishes to do—let readers in on the “fact” that one side in this litigation “doesn’t deserve to win”—is by doing what Greenhouse has done, namely become an opinion writer. A judgment about which side deserves to win a legal case is not a fact but an opinion. Even when it is authoritative, as it will be in this case when a majority of the justices hand down a ruling, it is still an opinion, often accompanied by differing opinions known as dissents and concurrences.

Greenhouse is not a judge, so her opinions are no more authoritative than those of your humble columnist. What’s more, on the merits, her opinion on the Obamacare case is shallow, disingenuous and silly:

I want to unpack the challengers’ Commerce Clause argument for what it is: just words.

Basically just one word, in fact: “unprecedented.” Did you know that the individual mandate is unprecedented? You will after you read the brief filed by the redoubtable Paul D. Clement, the former solicitor general, on behalf of the 26 states that filed suit to challenge the law. The brief uses the word “unprecedented” 10 times, by my count—I probably missed some—not counting such other formulations of the same thought as “novel” and “first ever.” O.K., I get it. I’ll even accept it as true: granted that passage of the Affordable Care Act ended decades of deadlock over how to reform the developed world’s most irrational health care system. It should have happened much earlier.

Unprecedented is a description, not an analysis.…The countless unprecedented things that Congress has done over the centuries were not, for that reason, unconstitutional.

Although I’ve elided some of Greenhouse’s verbiage, this is a fair representation of her argument, if one can call it that. It boils down to repeatedly sneering at the word “unprecedented” as if the litigants’ claim were no more than that Obamacare’s individual mandate is a new development in politics or policy. She simply ignored the legal significance of Obamacare’s lack of precedent.

That significance is great. “The command of precedent has deep roots in Anglo-American legal tradition,” one Supreme Court observer has noted. “Lawyers and judges often use the Latin phrase ‘stare decisis,’ meaning ‘to stand by things decided.’  ” The court has never decided the question posed by Obamacare: whether the Constitution’s Commerce Clause gives Congress the power to require that individuals purchase a financial instrument, or anything else, from a private company. Since no existing precedent authorizes the individual mandate, the court can strike down the Obamacare mandate without offending stare decisis.

The Supreme Court observer we quoted in the preceding paragraph was none other than Linda Greenhouse, writing in the Times in 1991. Unless she has forgotten such an elemental legal principle, her mockery of the litigants for noting that Obamacare is unprecedented was not merely ignorant but intellectually dishonest. She was trying to mislead her readers, and possibly herself, into thinking that the case against Obamacare is without merit:

If [as the court held in Gonzales v. Raich in 2005] the commerce power extends to backyard marijuana growing (as it did to backyard wheat growing in the famous New Deal case of Wickard v. Filburn), the notion that Congress somehow lacks the power to regulate, restructure or basically do whatever it wants in the health care sector, which accounts for 17 percent of the gross domestic product, is far-fetched on its face.

The justices may yet uphold Obamacare, but it was clear at oral arguments that the Greenhouse Effect wasn’t working. Justice Kennedy asked hard questions of the solicitor general, which signified that he does not share Greenhouse’s dismissive view of the arguments against the mandate. Even some of the liberal justices expressed concern about establishing a “limiting principle.” By the end of the week, it was the notion that the Constitution authorizes Congress to “basically do whatever it wants” that had come to seem far-fetched.

But not to President Obama. The week after the oral arguments, he told reporters: “I’m confident that the Supreme Court will not take what would be an unprecedented, extraordinary step of overturning a law that was passed by a strong majority of a democratically elected Congress.”

Obama was widely mocked for using Greenhouse’s favorite word, “unprecedented.” Unlike Clement, he deserved to be. Congress has been striking down unconstitutional acts of Congress since Marbury v. Madison in 1803.

THE NEXT DAY the president tried to clarify, saying: “We have not seen a court overturn a law that was passed by Congress on a [sic] economic issue, like health care, that I think most people would clearly consider commerce. A law like that has not been overturned at least since Lochner, right? So we’re going back to the ’30s, pre-New Deal.”

Wrong again. Lochner was decided in 1905, not the 1930s. The court did strike down some New Deal legislation, including the National Industrial Recovery Act in A.L.A. Schechter Poultry Corp. v. U.S. (1935). And Lochner, which involved a New York state regulation, had nothing to do with Congress’s powers under the Commerce Clause.

How could a onetime professor of constitutional law be so ignorant? He had answered that question as part of his initial remarks: “That’s not just my opinion; that’s the opinion of a whole lot of constitutional law professors and academics and judges and lawyers.” He might have added: and journalists like Linda Greenhouse. All those authorities told him the other side had no argument, and he believed it.

In 2005, Slate’s Dahlia Lithwick, a leftist legal journalist in the Greenhouse mold, scoffed at the idea of the Greenhouse Effect. She called it “a great conservative fiction: that there is vast, hegemonic liberal control over the media and academia. This may have been somewhat true once, but it’s patently untrue today.”

I’d say it might have been patently true once and is somewhat untrue today. But on the whole, it seems Lithwick was right. The Greenhouse Effect has given way to the Taranto Principle.