According to a lawsuit filed on Thursday, Mr Carlson falsely accused model Karen McDougal of extortion last year on his show Tucker Carlson Tonight, by saying that she “approached Donald Trump and threatened to ruin his career and humiliate his family if he doesn’t give them money”.
Ms McDougal claims in her lawsuit that she never threatened Mr Trump, and that the accusations would have been easily identified as false, if Fox News or Mr Carlson had attempted to fact check before airing.
The lawsuit faces a tough battle ahead, as the First Amendment makes it very difficult to win defamation lawsuits. Lawsuits like the one filed in New York State court are generally dismissed or settled before reaching trial.
When reached for comment, a Fox News spokesperson provided the following statement: “Fox News will vigorously defend Tucker Carlson against these meritless claims.”
Ms McDougal claims that she met Mr Trump in 2006 while he was filming Celebrity Apprentice, and that they then began a 10-month affair that was only ended because the model began to feel guilty that he was cheating on his wife, Melania Trump.
Mr Trump has denied that the pair had an affair.
Ms McDougal later sold the rights to her story to the National Enquirer for $150,000, in a process known as “catch and kill” by which media organisations buy the exclusive rights to potentially damaging stories about prominent allies and then bury them.
The Wall Street Journal was the first to report on that arrangement, just days before the 2016 election that ushered Mr Trump into the Oval Office. Conflicting narratives have emerged from there, with the Trump campaign claiming they had no knowledge of that payment to Ms McDougal, and a secret recording of Mr Trump discussing paying the Enquirer for the rights with his then-lawyer Michael Cohen last year.
In the lawsuit, Ms McDougal’s lawyer Eric Bernstein wrote that it does not matter which version is true when analysing the 10 December 2018 episode of Tucker Carlson Tonight in which the Fox News host allegedly defamed his client: “No matter which version of Trump’s statements one believes, Trump never once claimed that he was extorted.”