In May 2018, the nation's top Republicans needed help. So they called on the founder of Fox News, Rupert Murdoch.

President Donald Trump and Senate Majority Leader Mitch McConnell were trying to stop West Virginia Republicans from nominating Don Blankenship, who had been convicted of violating mine safety standards during a lethal accident in one of his coal mines, to challenge the state's incumbent senator, Democrat Joe Manchin.

"Both Trump and McConnell are appealing for help to beat unelectable former mine owner who served time," Murdoch wrote to executives at Fox News, according to court records released this week. "Anything during day helpful, but Sean (Hannity) and Laura (Ingraham) dumping on him hard might save the day."

Murdoch's prodding, revealed in court documents that are part of a defamation lawsuit by a voting systems company, is one example showing how Fox became actively involved in politics instead of simply reporting or offering opinions about it. The revelations pose a challenge to the credibility of the most watched cable news network in the U.S. at the outset of a new election season in which Trump is again a leading player, having declared his third run for the White House.

Blankenship, who ended up losing the primary, said in an interview Wednesday that he felt the change right away, with the network's coverage taking a harsher turn in the final hours before the primary.

"They were very smart about elections — they did their dumping the day before the election, so I had no time to react," said Blankenship, who filed a separate, unsuccessful libel suit against Fox.

On Wednesday, the network characterized Dominion Voting Systems' lawsuit as a flagrant attack on the First Amendment and said the company had taken statements out of context. According to Fox, that included an acknowledgement by Murdoch that he shared with Jared Kushner, the head of Trump's reelection campaign and the president's son-in-law, an ad for Joe Biden's presidential campaign that was to air on his network. Fox said the ad Murdoch forwarded to Kushner was already publicly available on YouTube and at least one television station.

"Dominion has been caught red handed again using more distortions and misinformation in their PR campaign to smear Fox News and trample on freedom of speech and freedom of the press," Fox said in a statement.

Fox has long been seen as a power in GOP politics with its large conservative fan base. But thousands of pages of documents released this week in the libel suit filed by Dominion show how the network blurred the line between journalism and party politics. Dominion sued after it became the target of 2020 election conspiracy theories, often promoted on Fox's airwaves.

Murdoch also told executives at Fox News to promote the benefits of Trump's 2017 tax cut legislation and give extra attention to Republican Senate hopefuls, the documents show. He wanted the network "banging on" Biden's low-profile presidential campaign during the height of the pandemic in 2020.

Nicole Hemmer, a Vanderbilt University history professor and author of the book "Partisans: The Conservative Revolutionaries Who Remade American Politics in the 1990s," said revelations in the lawsuit puncture Fox's long argument that there is a dividing line between its news and opinion sides.

"The real revelation here is how much of a fiction that division is," Hemmer said. "Some who know Fox have argued that for awhile, but now we have real evidence."

Hemmer cited text messages disclosed in the court documents from early November 2020 sent by Fox's chief political correspondent, Bret Baier, urging the network's leaders to retract its correct election night call that President Joe Biden won Arizona. Baier advocated for putting Arizona "back in his column," referring to Trump.

In the days after the election, as Trump was making increasingly wild allegations that fraud cost him the White House, Rupert Murdoch's son Lachlan Murdoch, who is executive chairman of the Fox Corp., texted with Fox News chief executive officer Suzanne Scott in alarm about a Trump rally.

"News guys have to be careful how they cover this rally," Lachlan Murdoch wrote, according to the legal documents. "So far some of the side comments are slightly anti, and they shouldn't be. The narrative should be this huge celebration of the president. Etc."

Some of Fox's politicking — like star host Sean Hannity's frequent conversations with Trump during his presidency — is well known. But court papers show how Rupert Murdoch, the boss, inserted himself in the action, too.

Murdoch emailed Scott in November 2017 and urged her to promote Trump's tax cut proposal, which had passed the House and was nearing a Senate vote.

"Once they pass this bill we must tell our viewers again and again what they will get," Murdoch wrote in the email, included in the court records. "Terrific, I understand, for all under $150k."

After the first presidential debate in 2020, a "horrified" Murdoch told Kushner that Trump should be more restrained in the next debate. (Trump canceled that event.)

"That was advice from a friend to a friend," Murdoch said in his deposition. "It wasn't advice from Fox Corporation or in my capacity at Fox."

"What's the difference?" asked Dominion's lawyer, Justin A. Turner.

"You've been — keep asking me questions as head of Fox," Murdoch said. "It's a different role being a friend."

Murdoch's email banter with Kushner led to the exchange of the Biden ad, according to court records. That exchange is now the subject of a complaint from the liberal watchdog group Media Matters for America to the Federal Elections Commission, arguing Fox made an illegal contribution to the Trump campaign by giving it information about Biden's advertisements. Fox said the sharing of public information can't be considered a contribution.

Court records show that on Sept. 25, 2020, Murdoch emailed Kushner that "my people tell me" that Biden's ads "are a lot better creatively than yours. Just passing it on."

The same month, Murdoch wondered in an email to Col Allan, the former editor of the Murdoch-owned New York Post, "how can anyone vote for Biden?" Allen responded that Biden's "only hope is to stay in his basement and not face serious questions."

"Just made sure Fox banging on about these issues," Murdoch responded, according to court records. "If the audience talks the theme will spread."

Another prominent politician Murdoch describes as a "friend" is McConnell, whose wife, Elaine Chao, then Trump's transportation secretary, had served on the Fox board. Murdoch said he would speak to the Republican Senate leader "three or four times a year."

In a special 2017 Republican Senate primary in Alabama, Murdoch said in his deposition, he told his top executives that he, like McConnell, opposed Roy Moore, a controversial former Alabama chief justice. Moore ultimately won the party's nomination but lost the general election after he was credibly accused of sexual misconduct, including pursuing relationships with teenagers when he was in his 30s. Moore denied the allegations.

Murdoch, in the deposition, also cited his personal friendship with an unnamed Senate candidate in his suggestion to Scott that the network give extra attention to Republicans in close Senate races.

Days before the 2020 election, after Fox business anchor Lou Dobbs was critical of Sen. Lindsey Graham, R-S.C., Murdoch asked Scott to have Hannity pump up Graham, who was facing an extremely well-funded challenge from Democrat Jamie Harrison.

"You probably know about the Lou Dobbs outburst against Lindsay Graham," Murdoch wrote on Oct. 27, misspelling the senator's first name in the copy of the message in the court documents. "Could Sean say something supportive? We can't lose the Senate if at all possible."

Scott replied that Graham was on Hannity's show the previous night "and he got a lot of time." She added, "I addressed the Dobbs outburst."