It was hard for anyone to know, in the course of Donald Trump’s presidential campaign, which of his pledges and threats to take seriously. Shortly after winning the election, he made it clear he would not attempt to prosecute Hillary Clinton, suggesting his “lock her up” rhetoric had been largely theater. On the other hand, one of his first major moves as president was to implement a travel ban that looked a lot like the Muslim ban he had called for on the trail. That punctured the argument, memorably advanced by Salena Zito in the Atlantic last September, that Trump’s more outrageous claims were not to be taken literally.

Right up there with Hillary Clinton and immigrants in Candidate Trump’s trinity of bêtes noires was the political press, aka the “media elite.” (It was only after his election that they became the “fake news media.”) At various points in his campaign, he emitted ominous noises about his plans for cracking down on press freedom, such as his February 2016 pledge to “open up libel laws” so that he could more easily win suits against news organizations when they write “hit pieces.” A year later, as president, he declared the news media “the enemy of the American people.” He added that he had directed the Department of Justice to open a crimininal investigation into the leaks that had allowed journalists a window into the early doings of his administration, including the fireable offenses of his first national security adviser, Michael Flynn. Putting two and two together, Washington Post media columnist Margaret Sullivan wondered then if Trump might go after journalists as well as leakers. “Some knowledgeable lawyers and academics say it’s unlikely,” she reported, suggesting that Trump might just be rallying the base. But she didn’t sound entirely reassured.

More recently, some commentators have questioned the sincerity of Trump’s attacks on the press, suggesting that his outrage and the media’s serve the interests of both sides. Politico Magazine wrote last month of Trump’s “fake war on the fake news.”

But it now seems clear that the war is real: Trump has every intention of using his power as president to punish journalists who cross him. On Tuesday night, the New York Times reported that, according to a memo written by James Comey, Trump had asked the then-director of the FBI to lay off of Flynn, who is under investigation—a possible obstruction of justice. But that’s not the story’s only chilling revelation. According to the Times, on Feb. 14 Trump made another request of Comey:

Alone in the Oval Office, Mr. Trump began the discussion by condemning leaks to the news media, saying that Mr. Comey should consider putting reporters in prison for publishing classified information, according to one of Mr. Comey’s associates.

It can’t really shock anyone, at this point, to learn that Trump apparently tried to use the FBI to muzzle the press. But it should scare people nonetheless. Unlike changing the libel laws, prosecuting reporters for publishing classified information is something that experts say Trump may actually have the power to do. And we should no longer delude ourselves that he would hesitate to do it.

The First Amendment laid down strong protections for the press, and courts have protected its freedom to publish classified information at important junctures in history. Famously, the Supreme Court ruled in 1971 that the Nixon Administration couldn’t stop newspapers from publishing the Pentagon Papers. Yet as James Risen explained in the Times in December, the Obama administration laid a troubling blueprint by invoking the World War I–era Espionage Act against journalists as well as leakers. (Obama was building on precedents set by his predecessor, George W. Bush, as NPR’s David Folkenflik recently explained.) Obama’s Justice Department eventually backed off, fearing a backlash, and then–Attorney General Eric Holder later said he regretted the overreach. The Trump administration, we can be confident, would have no such compunction.

“Publishing classified information has generally been considered a bedrock right of journalists,” Trevor Timm, executive director of the Freedom of the Press Foundation, told me in a phone conversation on Tuesday. “I think there is at least a broad consensus among the legal community that bringing such a prosecution would violate the First Amendment. But when you look at how the Espionage Act is written, it’s written so broadly that, just judging by the letter of the law, newspapers are violating it all the time.” Timm said he doubts the act could withstand constitutional scrutiny if applied in that way. Still, he added, “there’s nothing stopping the DOJ from trying to bring that case, and that’s what’s so disturbing. Even the specter of such a prosecution would certainly chill a lot of reporting.”

That might not sound like such a bad thing to those who believe classified information is meant to stay classified. But, Timm said, “In the past 40 to 50 years, virtually every really important story on national security or foreign policy that has been reported in major newspapers has contained classified info. If you outlaw journalists from publishing this type of information, it’s almost like outlawing journalism itself.”

Which might be just fine with Trump, who refers to real news as “fake news” and has also mused about canceling White House press briefings in favor of handing out written responses to questions. But it ought to trouble anyone who prefers a free society to an autocratic one, including Republicans.

It should—but perhaps it won’t. With the GOP in control of Congress and the Supreme Court, only Trump’s own party has the power to rein him in. But its unofficial mouthpiece, Fox News, has devoted itself to running interference for the president by treating everything he says as the truth while dismissing critical, fact-based reporting as liberal propaganda. Meanwhile, a recent Pew survey found that most Republicans no longer support a watchdog role for the media as a check on politicians’ power. The party, it seems, has evolved to accommodate its leader’s illiberal inclinations.

No one knew, when they voted for Trump, just what he would do if elected president. Many Republicans comforted themselves with the assumption that he wouldn’t actually carry out his more radical threats to upend democratic norms. Once again, that assumption has been exploded. Perhaps someday those who clung to it will be able to admit that they were wrong. The question is how much damage they’ll let him do first.