Fox Stars Privately Expressed Disbelief About Election Fraud Claims. ‘Crazy Stuff.’

Newly disclosed messages and testimony from some of the biggest stars and most senior executives at Fox News revealed that they privately expressed disbelief about President Donald J. Trump’s false claims that the 2020 election was stolen from him, even though the network continued to promote many of those lies on the air.

The hosts Tucker Carlson, Sean Hannity and Laura Ingraham, as well as others at the company, repeatedly insulted and mocked Trump advisers, including Sidney Powell and Rudolph W. Giuliani, in messages with each other in the weeks after the election, according to a legal filing made public on Thursday in a defamation lawsuit against Fox by Dominion Voting Systems.

“Sidney Powell is lying by the way. I caught her. It’s insane,” Mr. Carlson wrote to Ms. Ingraham on Nov. 18, 2020.

Ms. Ingraham responded: “Sidney is a complete nut. No one will work with her. Ditto with Rudy.”

Mr. Carlson continued, “Our viewers are good people and they believe it,” he added, making clear that he did not.

The messages also show that such doubts extended to the highest levels of the Fox Corporation, with Rupert Murdoch, its chairman, calling Mr. Trump’s voter fraud claims “really crazy stuff.”

On one occasion, as Mr. Murdoch watched Mr. Giuliani and Ms. Powell on television, he told Suzanne Scott, chief executive of Fox News Media, “Terrible stuff damaging everybody, I fear.”

The filing, in state court in Delaware, contains the most vivid and detailed picture yet of what went on behind the scenes at Fox News and its corporate parent company in the days and weeks after the 2020 election. It was during that period when the conservative cable network took an abrupt turn in its coverage.

Fox News stunned the Trump campaign on election night by becoming the first news outlet to declare Joseph R. Biden Jr. the winner of Arizona — effectively projecting that he would become the next president. Then, as Fox’s ratings fell sharply after the election and the president refused to concede, many of the network’s most popular hosts and shows began promoting outlandish claims of a far-reaching voter fraud conspiracy involving Dominion machines to deny Mr. Trump a second term.

What was disclosed on Thursday was not the full glimpse of Dominion’s case against Fox. The 192-page filing had multiple redactions. Fox has sought to keep much of the evidence against it under seal. The New York Times is challenging the legality of some of those redactions in court.

The details offer more than dramatic vignettes from inside a news organization where internal disputes rarely spill into public view and leakers are punished harshly. They are pieces of evidence that a jury could use to weigh whether to find Fox liable for significant financial damages. Dominion is asking for $1.6 billion as compensation for the damage it says it suffered as Fox guest and hosts claimed, for instance, that Dominion’s voting machines were designed for the purpose of rigging elections for the Venezuelan autocrat, Hugo Chavez, and equipped with an algorithm that could erase votes from one candidate and give them to another.

Fox Corporation has about $4 billion cash on hand, according to its latest quarterly earnings report.

The burden in the case falls on Dominion to prove that Fox acted with actual malice — the longstanding legal standard that requires Dominion to prove that Fox guests, hosts and executives either knew what was being said on the air was false and allowed it anyway, or that people inside Fox were recklessly negligent in failing to check the accuracy of their coverage.

That burden is difficult to meet, which is why defamation cases often fail.

In its defense, Fox has argued that by covering Mr. Trump’s fraud claims, the network was merely doing its job as any media organization would, by reporting and commenting on a matter of undeniable newsworthiness. The law shields journalists from liability if they report on false statements.

But endorsing or promoting falsehoods is not protected. Fox’s legal team has acknowledged that the former president’s claims were indeed false.

“This lawsuit assails the First Amendment and the news media’s duty and right to report on matters of significant public interest without fear of liability,” Fox said in the court documents filed on Thursday. “Freedom of speech and freedom of the press would be illusory if the prevailing side in a public controversy could sue the press for giving a forum to the losing side. Fortunately,” it added, “that is not the law.”

Many defamation suits are quickly dismissed because of the First Amendment’s broad free speech protections. If they do go forward, they are usually settled out of court to spare both sides the costly spectacle of a trial. The Dominion case has proceeded with a speed and scope that media experts have said is unusual.

For eight months, Dominion lawyers have taken depositions from dozens of people at all levels of the network and its parent company. Rupert Murdoch, chairman of Fox Corporation, was deposed last month. Sean Hannity, one of the most popular prime-time hosts and a close Trump ally, has been deposed twice. And many midlevel employees have had their personal phones and emails searched as part of the discovery process, which people inside the company have said has created an atmosphere of considerable unease.

Both sides appear dug in and confident of victory. The judge has scheduled jury selection to begin in mid-April.

Fox has contested how Dominion arrived at the amount it is seeking in damages, arguing that the company has vastly overstated its valuation and the reputational harm it suffered.

In papers filed with the court on Thursday, lawyers for Fox called the $1.6 billion sum “a staggering figure that has no factual support and serves no apparent purpose other than to generate headlines, chill First Amendment-protected speech, and unjustly enrich Dominion’s private equity owner.”

Fox’s lawyers added that Staple Street Capital Partners, the private equity firm that owns a majority share in Dominion, had only paid about $38 million for its 76 percent stake in the company in 2018 and had never estimated Dominion’s financial value to be worth “anywhere near $1.6 billion.” Fox has made a counterclaim against Dominion seeking to recover all its costs associated with the lawsuit.

Dominion’s goal, aside from convincing a jury that Fox knowingly spread lies, is to build a case that points straight to the top of the Fox media empire and its founding family: the Murdochs.

“Fox knew,” the Dominion filing declares. “From the top down, Fox knew.”