During the second 2016 presidential debate, Anderson Cooper asked Donald Trump whether his now-infamous boasts about kissing and grabbing women “by the pussy” in a 2005 Access Hollywood clip described Trump’s actual conduct. After initially dodging the question with the ambiguous claim that his comments were mere “locker room talk,” under persistent questioning from Cooper, Trump unequivocally denied that he had performed those acts. Since then, about a dozen women have come forward to contradict Trump’s denial, stating that they were victimized by Trump’s efforts to kiss, touch, or grab them in the way he described in 2005.

Trump has categorically denied all of these allegations. He claims that the women who accuse him are lying to gain fortune and fame, that they are acting at the behest of the Clinton campaign, and that the “rigged” media are complicit in promulgating their accusations without fact checking. Trump has also suggested that some of the accusers lack credibility because he finds them unattractive.

Trump’s denials themselves are dubious. He has pointed to no evidence of collusion with the Clinton campaign. Meanwhile, newspapers like the New York Times that have published the accusations did fact-check by seeking and finding other people to vouch for the stories—people who attested to the alleged victims having told them about the unwanted kissing and groping roughly contemporaneously with its occurrence.

That is not smoking-gun proof, of course. There remains the possibility that one or more of Trump’s accusers is misremembering or even fabricating.

But taken as a whole, Trump’s blanket denials look substantially less plausible than the obvious alternative explanation: Women who chose to keep silent for years decided to come forward after the second debate when Trump, through his denial, added insult to injury. Far from gaining fame and fortune, Trump’s accusers have been predictably rewarded by attacks.

The charges and counter-charges mostly have political salience. However, they may also have legal implications. During a recent speech at Gettysburg, Trump repeated his claim that his accusers are lying and threatened to sue each of them after the election.

Trump is probably bluffing but maybe not. A report commissioned by the American Bar Association (ABA) recently concluded, based on an examination of Trump’s litigation history, that he is a “libel bully” who brings lawsuits to intimidate his critics. These lawsuits are potentially effective in that goal even if they ultimately lose in court. Ironically, the ABA did not publish the report, apparently out of fear that doing so would lead Trump to file a bullying lawsuit against the organization itself.

Even if Trump is bluffing, litigation could be on the horizon. As I shall explain, by accusing his accusers of lying, Trump opened the door to lawsuits against himself.

Trump as Plaintiff

Libel and slander are state torts governed by state law. However, because these torts are accomplished through (respectively) written and spoken words, they implicate the First Amendment.

Most fundamentally, it is now generally accepted that the First Amendment forbids criminal penalties for defamation. Although many early Americans thought this principle had been established by the acquittal of New York printer John Peter Zenger in 1735, the Congress that enacted the Sedition Act in 1798 ignored it. Nonetheless, modern free speech law is widely seen as repudiating seditious libel as inconsistent with our Constitution. In addition, the First Amendment has been understood to forbid even civil defamation liability for true statements (although other tort suits, such as invasion of privacy, can sometimes succeed based on the dissemination of true information).

Modern case law added an additional constitutional overlay to state defamation law. In the 1964 case of New York Times v. Sullivan, the Supreme Court held that liability for defamation cannot rest on the making or publishing of a mere false statement about a public official; liability can only attach based on what the Court called “actual malice,” defined to mean something like deliberately publishing false information. A strict liability standard under which mere falsehood establishes liability, the Court concluded in Sullivan and subsequent cases, would unduly chill freedom of speech.

Donald Trump is not a public official and will not become one if he loses the election. However, in the 1971 case of Monitor Patriot Co. v. Roy, the Supreme Court extended the Sullivan standard to apply to candidates for public office as well, and even apart from that decision, another line of cases extends Sullivan to defamation suits by “public figures.” If anyone is a public figure, it is Donald Trump.

Accordingly, if Trump were to sue any or all of his accusers for defamation, he would have the burden of proving not merely that they were mistaken in recalling Trump’s having kissed or groped them against their will, but that they knew their stories were false. That is a very difficult burden to satisfy, which is why lawsuits brought by Trump would almost certainly lose.

Lawsuits Against Trump

If Trump does follow through on his plan to sue his accusers, each of them could counterclaim with their own defamation suit. Under the common law of most states—including Pennsylvania, where Trump made his claim that his accusers were lying—calling someone a liar can be the basis for a defamation suit.

If Trump had not publicly charged his accusers of lying, his mere filing of a defamation suit against any of them could not give rise to the accuser’s own counterclaim for defamation, because allegations in a court-filed complaint cannot be considered defamation. Moreover, because the alleged kissing and groping took place many years ago, the accusers could not file counterclaims for battery or other torts, because the relevant statutes of limitations have run. But by publicly calling his accusers liars in a non-judicial setting, Trump reset the clock and opened the door to new defamation claims against himself.

Furthermore, it is possible that claims by Trump’s accusers against him would not be judged by the demanding Sullivan standard—which only applies to claims by office-holders, candidates, and public figures, not to claims against such people. To be sure, it is also possible that an accuser could be deemed a public figure herself if, as the Supreme Court put it in the 1976 case of Time, Inc. v. Firestone, she “thrust herself to the forefront of any particular public controversy in order to influence the resolution of the issues involved in it.” That is arguably true of Trump’s accusers, although case law does not definitively resolve whether an otherwise private person becomes a public figure for First Amendment purposes simply by publicly alleging that she was the victim of a crime or tort.

If the Sullivan standard does not apply to claims lodged against Trump by his accusers, then Trump could be found liable for slander even if a jury or judge concludes that he did not kiss or grope an accuser against her will, so long as the accuser believed in good faith that he did so. An accuser who merely misremembered an incident with Trump would not be a liar, and thus Trump’s claim that she was lying would be defamatory.

Finally, Trump’s public accusations against his accusers open the door to litigation against him even if he does not follow through on his threat to sue them. One or more of them could sue him.

Indeed, Trump’s accusers could probably band together to sue him in a single lawsuit, because he claimed they were lying in a single statement. Such a multi-accuser lawsuit against Trump would be especially powerful, because the women’s stories are mutually reinforcing. It is possible to believe that an individual woman claiming to have been unwillingly kissed or groped by Trump is mistaken or lying, but taken together, the accusations from multiple women without prior connections over the course of many years present a pattern of behavior by Trump that is nearly impossible to explain away, absent proof of an anti-Trump conspiracy that has thus far been completely lacking.

Already, top lawyers have offered to defend Trump’s accusers pro bono should he sue them. If the accusers can find representation to bring their own lawsuit, they might be able to do more than resist the libel bully. They might be able to make him pay.