As Paul Manafort, President Trump's former campaign chairman, was being booked at the Washington headquarters of the Federal Bureau of Investigation on Monday, Oct. 30, Time Warner Inc.'s (TWX) CNN was doing what it's been doing for months: focusing on the possibility that the Republican president colluded with Russian operatives in an effort to win election in November.

"This is not a good day for the White House," CNN political analyst Amie Parnes said on air.

For AT&T Inc. (T) - Get Report , Trump's running war with CNN and its president, Jeff Zucker, has been at best a distraction and at worst a cause for concern. Publicly, AT&T CEO Randall Stephenson has proclaimed his support for CNN and his belief that the Department of Justice's Antitrust Division ultimately will approve the $85.4 billion transaction. Stephenson, though, hasn't said much publicly about the future of CNN President Jeff Zucker, a point that has made for uneasiness at the network, Vanity Fair's Joe Pompeo reported on Sunday. 

Trump, meanwhile, has called CNN all sort of things, from "fraud news" to "garbage journalism," while singling out the network as the lead player in a "witch hunt" meant to "get Trump."

"CNN adopted a very aggressive posture towards covering this administration," said Frank Sesno, director of George Washington University's School of Media and Public Affairs and a former CNN Washington bureau chief. "I have no reason to think that those who are attacking the media are going to let up. If anything, they'll intensify."

The testy battle between Trump and CNN began in June 2016 when the New York real estate developer announced his candidacy for the Republican nomination by calling Mexican immigrants rapists and criminals. In recent months, Trump has escalated his attacks at CNN, accusing the network of mendacious reporting even as rival news outlets confirmed its reports. 

In July, Trump posted a video of himself as a professional wrestler, body slamming CNN:

A day earlier, he was more direct: 

At CNN, though, Stephenson's reluctance to publicly back Zucker has put network employees and others at the company on edge, Pompeo reported. Trump was said to have pushed for Zucker's removal as a prerequisite for DOJ approval, The New York Times reported on July 5. Of course, Trump is said to have adored Zucker when he embraced "The Apprentice" while president of NBC Entertainment.

CNN's reporting has been substantiated despite a couple of well-publicized snafus, observed Joe Peyronnin, a media studies professor at Hofstra University and a former president of Fox News. The network removed three top editors in June after retracting a story about former White House press secretary Anthony Scaramucci, and parted ways with Kathy Griffin and Reza Aslan, neither of whom worked in the network's newsroom, after their profane attacks on the president.

But apart from those episodes, CNN's reporting has stood the test of public scrutiny, he said. CNN, after all, broke the story on Friday that a federal grand jury had approved the first charges in special counsel Robert Mueller's Russia investigation. 

"CNN has had to retract one story in all this time, and what, They had to apologize for a couple of people who are not staff members making comments?" Peyronnin said. "By and large, CNN is doing a very skilled and quality job providing the news. I'm sorry the president doesn't like it, but what they're reporting is proven accurate."

AT&T declined comment on the Vanity Fair story and the ongoing regulatory process.

The company's shares on Monday afternoon were down 1.2% to $33.55, while Time Warner stock had shed 0.3% to $98.46.

On Monday, CNN's reporting on possible ties between Trump and Russian operatives appeared to have found support in Mueller's indictments. Manafort was charged with funneling millions of dollars through overseas shell companies and then using that money to buy luxury cars, real estate, antiques and expensive suits. A former Trump campaign policy adviser, George Papadopoulos, also pleaded guilty to lying to the FBI about a contact with a professor with ties to the Russian government. Manafort, who oversaw the Trump campaign from March 29 through Aug. 19, was accused of laundering more than $18 million.

As the Mueller investigation moves on, CNN and the rest of the media covering the Trump presidency need to be more careful than ever, Sesno said. Any misstep will be used by Trump and his supporters to paint a picture of the media as less interested in the truth than about taking down a president.

"If the media make errors, the attacks are going to land even more destructively," Sesno said. "And not incidentally, the public doesn't have a great deal of trust in the media right now. So in reporting such a high-profile, high-decibel story, they gotta get it right."

The Manafort indictment, coming as it does from a special counsel rather than a media outlet, could offer CNN some comfort. In the weeks ahead, Trump's attention likely will be focused on the Mueller investigation rather than a deal combining the country's largest pay-TV provider with a sprawling media and entertainment company.

"It would be inappropriate and truly tragic if the federal government decided not to let a merger go ahead based on the fact that one of the elements, CNN, is critical of the president," Peyronnin added. "This has to be strictly a business decision."

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