Among President Trump’s few animating principles is his deep and abiding belief that the libel laws were created for his personal enrichment. Thus it should have surprised no one when White House chief of staff Reince Priebus said over the weekend that Trump may seek to dismantle a vital protection against libel suits for journalists who report on matters of public interest.

“I think it’s something that we’ve looked at,” Priebus said on ABC News’ “This Week” in response to a question by Jonathan Karl. “How that gets executed or whether that goes anywhere is a different story.” Priebus added that news organizations must “be more responsible with how they report the news.”

In its simplest form, libel is defined as a statement that is false and defames another person. Since the 1960s, public officials and public figures who sue for libel have had to prove not just those two elements but also that the statement was published with the knowledge that it was false or with reckless disregard for the truth — a legal standard known as “actual malice.” The idea is to protect journalists from potentially ruinous libel actions arising from reporting that is erroneous but not fundamentally dishonest. Although Trump has not been clear about what he would do, he presumably would like to weaken the actual malice requirement.

Trump is no stranger to filing libel suits. In 2006 he sued the journalist Timothy O’Brien for claiming in his book “TrumpNation” that the alleged billionaire might be worth as little as $150 million to $250 million. Trump lost, but the trial and the appeals process kept O’Brien tied up for years. In an interview for The Washington Post’s biographical book “Trump Revealed,” he called O’Brien a “low-life sleazebag” and said he sued him because he knew it would “cost him [O'Brien] a lot of money.” And he issued an ominous warning:

Now, libel suits are very hard and I may look at that, frankly, if I get elected, because it’s very unfair that somebody could write whatever they want to write and get away with it. And I will be bringing more libel suits — maybe against you folks. I don’t want to threaten, but I find that the press is unbelievably dishonest.

Trump’s best-known assault on libel protections came in February 2016. In a speech in which he attacked the Post and The New York Times for writing “hit pieces” against him, he said that if he were elected, “I’m going to open up our libel laws so when they write purposely negative and horrible and false articles, we can sue them and win lots of money.”

And as recently as March 30 of this year, Trump took to Twitter and once again raised the specter of changing the libel laws, this time in response to some provocation from the “failing” New York Times:

The failing @nytimes has disgraced the media world. Gotten me wrong for two solid years. Change libel laws?— Donald J. Trump (@realDonaldTrump) March 30, 2017

The modern standard for proving libel arose from the civil-rights movement. In 1960 the Times published a full-page ad placed by supporters of the Rev. Martin Luther King Jr. titled “Heed Their Rising Voices.” There were several minor errors in the ad. And though a fair reader would conclude that the gist of it was accurate, an Alabama state jury ruled in favor of the Montgomery police commissioner, L.B. Sullivan, who had sued for libel.

That led to a landmark 1964 ruling by the U.S. Supreme Court. In Times v. Sullivan, the court ruled that public officials could not use the libel laws to suppress public discussion of important issues even in the face of falsehoods, provided that those falsehoods were not published knowingly or recklessly. In a unanimous opinion, Justice William Brennan said the new standard was needed to protect the idea that “a profound national commitment to the principle that debate on public issues should be uninhibited, robust, and wide-open, and that it may well include vehement, caustic, and sometimes unpleasantly sharp attacks on government and public officials.” (The Times v. Sullivan case is covered at book length in the late Anthony Lewis’ wonderful “Make No Law: The Sullivan Case and the First Amendment.”)

So how likely is it that Trump would try to turn the clock back? And how likely is it that he would succeed?

On the face of it, any change to the Sullivan standard would seem to be a longshot. Even CNN’s Trumpster-in-residence, Jeffrey Lord, has expressed opposition, saying, “I confess, as a First Amendment freak, that does bother me a bit.” (OK, make that mild opposition.)

Moreover, a mere law would have little effect, since it would be trumped, as it were, by the Sullivan decision. There is virtually no chance that the Supreme Court as it is currently constituted would overturn Sullivan. The newest justice, Neil Gorsuch, appears to be of one mind with his fellow conservatives, who are staunch defenders of the First Amendment. Nor does it seem likely that a constitutional amendment could be approved, as passage would be required by two-thirds of both branches of Congress and three-fourths of the state legislatures.

But there is one route that would appear to be a remote yet real threat: a constitutional convention, which has been sought over the years by some conservatives to enact such measures as a balanced-budget amendment. Such a convention may be called by just two-thirds of the states. And some scholars believe that once the delegates have gathered, they could change the Constitution in any way they like, although a three-fourths vote would be required for passage. As Harvard Law School professor Laurence Tribe has said, calling a convention would amount to "putting the whole Constitution up for grabs."

The high barrier to successful libel suits that Times v. Sullivan established is a vital bulwark against an oppressive government. The trouble with Trump is that you never know when he actually means something or is just running his mouth. But in an era when the president has called the news media “the enemy of the American People,” we need to remain vigilant in defense of a free and independent press.