Fox News’s reputation as an unyielding backer of Donald Trump is in tatters after revelations that many of its top executives and on-air personalities never believed his lies about the 2020 election, and even personally disliked the former US president.

The details stem from documents released as part of a $1.6bn defamation lawsuit brought against the network by Dominion Voting Systems, a voting machine firm Trump and Fox News singled out for unfounded allegations of rigging in the aftermath of the presidential race two years ago.

The case is viewed as potentially the biggest financial threat to Fox News since it came on the air in 1996, but the details that have trickled out have already reshaped views of the network and shown a broad gulf between what its top personalities tell their viewers in public and what they privately believe.

Here are the key things to know:

When did the lawsuit begin?

Dominion sells voting machines and tabulators and has headquarters in Denver, Colorado and Toronto, Ontario. It filed its lawsuit in March 2021, claiming Fox News spread lies about the 2020 election in an effort to stop viewers from switching to other networks.

The firm’s complaint singled out some of Fox’s biggest personalities, such as Maria Bartiromo, Tucker Carlson, Lou Dobbs, Sean Hannity, Jeanine Pirro “and their chosen guests”, saying they plucked “defamatory falsehoods” from obscure far-right websites and broadcast them to their tens of millions of viewers. “Fox took a small flame and turned it into a forest fire,” Dominion said.

When will the case go to trial?

The trial is scheduled to begin on 17 April, and expected to last five weeks.

Why do we know so much about behind-the-scenes happenings at Fox News?

Dominion began making evidence in the case public in mid-February as part of court filings, which included emails and text messages exchanged between Fox News personalities and executives, as well as depositions made as part of the suit.

What did Fox News hosts really think about the 2020 election?

Even as they went on the air to cast doubt about whether the vote went off fairly, many Fox News personalities privately doubted Trump’s claims. “He’s acting like an insane person,” Hannity, one of the network’s best-known personalities, allegedly said of Trump, according to a Dominion court filing.

They also released messages from the Fox News owner, Rupert Murdoch, in which he wrote that it was “very hard to credibly claim foul everywhere”, and the then president’s insistence on doing so was “terrible stuff damaging everybody”.

Carlson, Fox’s most popular commentator, took aim at Sidney Powell, a top lawyer for Trump who repeatedly claimed on air that Dominion’s machines changed votes from Trump to his Democratic opponent Joe Biden. “Sidney Powell is lying,” Carlson wrote to a producer, later calling her “dangerous as hell”.

Murdoch also said that several of the network’s top stars “endorsed” Trump’s false claims, and “I would have liked us to be stronger in denouncing it in hindsight,” according to a deposition in the case.

What do we now know about their views of Donald Trump?

Publicly, Trump has few friends like the personalities on Fox News. Privately, some of them loathe him. The case’s filings reveal that Carlson, for instance, wrote of Trump: “I hate him passionately … What he’s good at is destroying things. He’s the undisputed world champion of that. He could easily destroy us if we play it wrong.”

Murdoch felt that Trump and his attorney Rudy Giuliani were “both increasingly mad. The real danger is what he might do as president.” And on 4 January, two days before Trump riled up a crowd of supporters who went on to attack the US Capitol, Carlson wrote in a text, “We are very, very close to being able to ignore Trump most nights.

“I truly can’t wait.”

Why did Fox News continue promoting election lies?

With competitors like Newsmax and One America News Network waiting in the wings, Fox executives apparently feared losing their dominant place among America’s conservative viewership if they broke with Trump over the 2020 election.

“We need to be careful about using the shows and pissing off the viewers,” Fox News’s chief executive, Suzanne Scott, told Murdoch the day before the January 6 attack.

The network’s concern with maintaining advertising revenue also comes through in the documents. “It is not red or blue, it is green,” Murdoch said in his deposition, when asked why Fox allowed the conspiracy theorist Mike Lindell to run ads for his MyPillow product on the network.

Fox has released its own evidence to argue against some of Dominion’s assertions, including comments from the Fox Corp co-chairman and CEO, Lachlan Murdoch, who said he was “concerned” but “not overly concerned” by a dip in the network’s ratings after the 2020 vote.