Liberals discover a theory to crush conservative jurisprudence.

AT THE END OF MARCH, when Solicitor General Donald Verrilli appeared before the Supreme Court to make the case for the Affordable Care Act, he was widely perceived to have choked. When he approached the podium in the packed courtroom, the stakes could not have been higher. Verrilli was defending the Obama administration’s central domestic achievement, a reform that had consumed the White House for the better part of the president’s first term. His opponent, Paul Clement, was the most sought-after Supreme Court advocate in the country, with a knack for producing a crisp answer to any question a justice could lob his way. Verrilli, a laconic former corporate litigator, had argued many cases before the Court, but he was new to his job—he’d been confirmed to succeed Elena Kagan less than a year before—and also new to the types of constitutional arguments at the heart of the health care case.

The first day of the oral arguments passed without incident. On the second day, the subject under discussion was the individual mandate—the most controversial part of the law—and, as soon as Verrilli launched into his defense of it, he ran into trouble. “Insurance has become the predominant means of paying for health care in this country,” he began, and then coughed, cleared his throat, and coughed again. “Insurance has become the prominent means of paying for health care in this country,” he continued. “For most Americans—for more than eighty percent of Americans, the insurance system does provide effective access”—he took a sip of water—“Excuse me. But, for more than forty million Americans who do not have access to health insurance either through their employer or through government programs, such as Medicare or Medicaid, the system does not work.” Later that day, audio clips of the most awkward moments proliferated on a variety of websites; the Republican National Committee spliced them together for an attack ad with the tagline: “Obamacare: It’s A Tough Sell.”

Meanwhile, the legal academy was subjecting Verrilli to a more esoteric form of Monday-morning quarterbacking. And, in the view of one group of law professors, Verrilli’s hapless presentation was the least of his sins. To these scholars, the greater problem was his entire line of reasoning. Verrilli, they maintained, had failed to invoke the most powerful constitutional defense of the law—a defense that could have proved especially persuasive to the conservative justices.

Einer Elhauge of Harvard Law School, for example, pointed out that the Founders had explicitly endorsed the concept of a health care mandate when the first Congress passed legislation in 1790 requiring shipowners to buy health insurance for their sailors. This law was signed by President George Washington. Taking a different angle, Jack Balkin of Yale Law School argued that the mandate is clearly authorized by Article I, Section 8, of the Constitution, which permits Congress to “lay and collect taxes.” Rather than getting tangled in the wonky particulars of exactly when individuals enter the health care market, these scholars were locating a justification for the law in the text of the Constitution and the historical understanding of the men who wrote and ratified it.

This approach was striking, because for a long time, conservatives alone worshipped at the temple of originalism—that is, the belief that the highest legal authority in the United States is the original meaning of the nation’s Founding document. For decades, the right brandished originalist arguments to potent political effect, casting conservative judges as sober adherents to the Constitution and liberal judges as uninhibited meddlers. In recent years, however, a growing movement on the legal left has sought to fashion its own version of originalism. Its proponents—known less than pithily as the New Textualists—insist that arguments grounded in constitutional text and history can be deployed just as effectively to support liberal policies as conservative ones.