Even before he became a Republican presidential candidate, Donald Trump frequently made factually questionable pronouncements and stretched the bounds of credulity. And the real estate tycoon’s recent announcement about how he planned to “open up” U.S. libel laws if elected arguably also falls into this category.

Is such a thing possible? Theoretically, maybe. Is it likely to ever happen? No, because it would require an all-out battle against the First Amendment.

Trump has spent much of his campaign railing against the liberal media including newspapers such as the New York Times and the Washington Post, which he claims are “dishonest scum” for a variety of reasons—primarily because they write articles critical of him and his campaign platform. At a rally in Texas last week, however, the candidate expanded on his dislike of the press, and said that he planned to make it easier to sue the media if he is elected president.

“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,” Trump said. “We’re going to open up those libel laws. So when The New York Times writes a hit piece which is a total disgrace or when The Washington Post, which is there for other reasons, writes a hit piece, we can sue them and win money instead of having no chance of winning because they’re totally protected.”

Not surprisingly, Trump’s remarks triggered outrage among the media because it amounts to a head-on attack against the principle of a free press—a fundamental element of the U.S. democratic system. But it’s likely that Trump’s promise is mostly bluster.

For one thing, there is no federal libel law for Trump to “open up.” Libel is something that is regulated at the state level, which means that to change it, the president would have to either convince all of the states to change the way they handle libel prosecution or pass a new federal law specifically governing libel. And if he were to try and do that, Trump would run into a very large obstacle known as the First Amendment.

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After Trump made his comments, an opinion writer at the New York Daily News reached out to Floyd Abrams, an attorney who is an expert in constitutional law, about the likelihood of this promise coming true. And Abrams confirmed that there is little chance. “There is no federal libel law for Trump to amend or change, and thus no role for the President at all,” Abrams said. “Fifty states have their own libel laws; the federal government has none.”

The only federal law that governs libel, Abrams said, is the First Amendment. “So when Trump says he wants to ‘open up’ libel law, he really means (if he has the slightest knowledge of the law) that he wants to open up—to change—the First Amendment, which, beginning in 1964, has been held to require in cases brought by public figures, proof that what was said was false, and that the newspaper knew or suspected that it was false. In short, he simply doesn’t know what he’s talking about.”

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In referring to 1964, Abrams is talking about the landmark Sullivan vs. New York Times case, in which the Supreme Court established what’s known as the “malice standard” for libel. That case involved a newspaper ad that was intended to raise funds for Martin Luther King Jr., and mentioned the behavior of the Alabama police department, as well as other state authorities. An Alabama official sued for libel and won, but the Supreme Court overturned the case.

For Trump to make good on his claim that he would “open up” libel laws, in other words, he would have to attack the First Amendment head on by trying to pass a law that would make it easier to sue—in blatant disregard of the Supreme Court. He could try and do this (assuming he becomes president) by doing a number of things, including stacking the court with judges favorable to his views. But it would not be as easy as Trump likes to make it sound during his campaign rallies.