On Tuesday, Justice Clarence Thomas made a stunning announcement: The justice wants to overturn perhaps the most important free expression ruling in the Supreme Court’s history, New York Times v. Sullivan. That precedent, against which Thomas casually proclaimed war while voting to deny cert in the defamation case McKee v. Cosby, sharply limits the ability of public figures, including government officials, to sue their critics for libel. It remains the crucial safeguard of America’s free press, a bulwark against defamation suits designed to silence media outlets and chill public debate. If Thomas succeeded in killing off Sullivan, it would be, quite simply, the end of the First Amendment as we know it.

Decided in 1964, Sullivan was a disturbing illustration of how public officials could exploit libel laws to censor their critics. The case involved a full-page advertisement that civil rights advocates ran in the New York Times in 1960 condemning the Montgomery, Alabama Police Department. Titled “Heed Their Rising Voices,” the ad solicited funds to defend Martin Luther King Jr. against an Alabama perjury indictment. In describing state law enforcement’s abusive response to civil rights demonstrations, the ad made several factual errors—claiming, for instance, that King was arrested seven times, instead of four. It was, however, largely factual, and designed to alert readers nationwide of the police misconduct directed toward civil rights demonstrators in the South.

In the early 1960s, only about 400 copies of the New York Times were circulated in Alabama. Yet Montgomery Public Safety Commissioner L.B. Sullivan responded to the ad with a $500,000 lawsuit, alleging that it had defamed him in his capacity as supervisor of the police. Sullivan’s suit was part of a campaign among Southern segregationists to hobble newspaper coverage of racial injustice. By 1964, Southern officials had brought almost $300 million in libel claims against the press for (truthfully) reporting on civil rights abuses. The trial judge who heard Sullivan’s claim had announced his belief in “white man’s justice” and written a disquisition called The Confederate Creed. He found the Times guilty of libel; the jury then awarded Sullivan the full $500,000, a judgment that the state Supreme Court upheld. (These facts are detailed in Anthony Lewis’ famous book Make No Law.)

When the U.S. Supreme Court agreed to hear the New York Times’ appeal, the justices were widely expected to reverse the verdict. They did, unanimously—but Justice William Brennan’s majority opinion went further than that. Brennan announced a new constitutional standard for libel claims against public officials under the First Amendment. To win a defamation case, Brennan wrote, plaintiffs must prove the defendants acted with “actual malice.” That means the defendants published an accusation “with knowledge of its falsity or with reckless disregard of whether it was true or false.” Sullivan, Brennan noted, plainly did not prove the Times acted with actual malice.

Among civil libertarians and the press, the court’s decision was celebrated as a signal victory for the First Amendment. Philosopher and free speech advocate Alexander Meiklejohn called it “an occasion for dancing in the streets.” And rightly so: The decision effectively ended segregationists’ campaign to drive Northern newspapers out of business, or at a minimum, cut their circulation in the South. It also vastly expanded “breathing space” for the press under the theory that “debate on public issues should be uninhibited, robust, and wide-open.” After Sullivan, “vehement, caustic,” and “unpleasantly sharp attacks” on public officials could no longer be silenced through libel lawsuits.

Thomas’ desire to champion the pro-censorship Framers is just as “policy-driven” as Sullivan.

Over the next few decades, the Supreme Court applied Sullivan’s actual malice standard to public figures who were not government officials, like celebrities. It also extended the rule to other kinds of lawsuits by public figures designed to punish the press, such as intentional infliction of emotional distress. There are certainly legitimate criticisms of Sullivan and its progeny; in a 1993 review of Make No Law, now-Justice Elena Kagan noted that while the ruling “appears justified, correct, even obvious,” it may arguably be blamed for “increased press arrogance.” There is also a strong argument that individuals who have been “involuntarily thrust into a public controversy” should not have to meet the high bar of actual malice to obtain damages for defamation. But the fundamental premise of Sullivan—that the First Amendment restricts libel suits brought by public officials—remains a bedrock principle of constitutional law.

Thomas wants to change that. On Tuesday, he used McKee v. Cosby as a vehicle to urge the abolition of Sullivan and its many successors. The optics are savvy: McKee involves a lawsuit brought by Kathrine McKee, who accused Bill Cosby of raping her, and of defaming her when she spoke out. A lower court found that McKee is a public figure who must prove actual malice to obtain damages. She is obviously an extremely sympathetic plaintiff, and Thomas was shrewd to use her case to assault Sullivan. He described that line of rulings as “policy-driven decisions masquerading as constitutional law” and insisted that they did not align with the “original meaning” of the Constitution. Calling for the court to overturn them all, Thomas wrote: “The States are perfectly capable of striking an acceptable balance between encouraging robust public discourse and providing a meaningful remedy for reputational harm.”

This opinion is startling in two respects. First, the Supreme Court departed long ago from a strict adherence to Thomas’ view of the First Amendment’s original meaning. Some Framers took a restrictive view of free speech, arguing that the government could criminalize criticism of public officials. Others, like James Madison, vigorously disagreed, and for decades the court has generally taken his side. Thomas’ desire to champion the pro-censorship Framers is just as “policy-driven” as Sullivan. (In fact, Brennan’s opinion did delve into the historical record and marshaled historical evidence for its conclusions.)

The second, more disturbing aspect of Thomas’ opinion is his claim that states can be trusted to craft and enforce their own libel laws without First Amendment limitations. This assertion is patently false. Before Sullivan, some states allowed libel plaintiffs to triumph even if the allegedly defamatory statement was proved true, so long as it was published with hostility toward the plaintiffs. Moreover, defamation was both a civil offense and a crime—and the truth was no defense to libel prosecutions in many states. As Thomas noted, criminal defamation laws were “intended to punish provocations to a breach of the peace, not the falsity of the statement.” In other words, individuals could be prosecuted and imprisoned for truthfully criticizing government officials.

Perhaps Thomas believes that, in 2019, states would not prosecute individuals for criticizing public officials out of respect for free speech. If so, he is wrong. In 2018, New Hampshire law enforcement arrested a man for criticizing a police chief online. The American Civil Liberties Union of New Hampshire has filed a lawsuit alleging that New Hampshire’s criminal defamation statute violates the First Amendment under Sullivan. Twenty-three other states have similar statutes that can be used to imprison critics of the government. Does Thomas view these laws as “striking an acceptable balance” between free speech and “reputational harm”?

He might. Thomas reportedly once said that “one of the happiest days of my life was when I cancelled my Washington Post subscription,” and he is famously hostile to the media. His views on free press appear to align with those of President Donald Trump, who has pledged to “open up our libel laws.” Thomas seems to agree with Trump that it’s time to let public officials resume censoring their critics through crippling libel lawsuits. L.B. Sullivan would be delighted.