Brian Stelter of CNN, left, and Sean Hannity of Fox News are among the dueling personalities at the rival networks. (Jesse Dittmar for The Washington Post; Carolyn Kaster/Associated Press/TWP;AP)

When a young survivor of the Parkland, Fla., school shooting accused CNN of trying to “script” his questions for its town-hall-style telecast last week, Fox News’s opinionated hosts Tucker Carlson and Laura Ingraham jumped on the story.

Carlson interviewed the teenager, Colton Haab, on his prime-time program, and expressed amazement at CNN’s supposed attempt to manipulate him: “It’s shocking to us, too, trust me, in the actual journalism business.” Ingraham added her own sneer, commenting that CNN has “a history of planting questions.”

No matter that the actual facts would quickly exonerate CNN, which released emails showing that the network had simply invited Haab to ask its panel of politicians a question he’d previously voiced. The dust-up had an irresistible attraction for Fox: It was another chance to beat up its cable news competitor.

The two networks are long and bitter rivals, of course, and have tweaked each other off and on since Fox News’s inception in 1996. But the crossfire has taken on new intensity in the Trump era. Hosts at CNN and Fox now trade blows almost daily about whose coverage or commentary about President Trump is more distorted or unfair.

Fox, for example, aired multiple clips of CNN’s “town hall” about gun violence last week, using it to call out “liberal” media bias in the debate over gun control. Hannity had the National Rifle Association spokeswoman Dana Loesch on his program to talk about her experience on the CNN broadcast; an on-screen banner said she had been “heckled, interrupted and called a ‘murderer’ ” at the event.

For its part, CNN has frequently found something newsworthy in whatever Fox’s host are opining about. After Ingraham criticized National Basketball Association superstars LeBron James and Kevin Durant for expressing their political opinions (“Shut up and dribble,” she said), CNN aired a news segment about her comments in which host Brooke Baldwin pointed out that Fox sometimes gives celebrities such as Kid Rock, Chuck Norris and Phil Robertson a platform for their political opinions.

Both networks have aired or published online dozens of articles about the other in recent months, playing up such topics as ratings, various mistakes and embarrassing missteps by the other, and even coverage of the Winter Olympics.

The mutual backbiting between the two has become so routine that it can be easy to forget how unusual it is. NBC News doesn’t regularly lay into ABC News; The Washington Post doesn’t often go after the New York Times. Nor do CNN or Fox criticize other news media outlets as frequently as they do each other.

In many ways, the Hatfields-and-McCoys act has become a proxy for the news media’s drift into more polarized camps, especially when it comes to covering Trump. The president has certainly stoked the perception that there are pro- and anti-Trump factions in the news media, singling out CNN and Fox in particular. He often praises Fox and its hosts, and he grants the network periodic interviews. At the same time, he has demonized CNN in comments and tweets as a purveyor of “fake news.” (For the record, both networks reject the notion that they are pro- or anti-Trump, or that they are “liberal” or “conservative.”)

But the sniping is also “a business strategy” that reflects the networks’ efforts to differentiate themselves at a time when so much news is shared and consumed via social media, said Gabriel Kahn, a professor at the University of Southern California’s Annenberg School of Communication.

Since “highly emotional” news is the kind that travels furthest on social platforms such as Facebook and Twitter, he said, both networks have an incentive to jab each other.

“CNN can no longer afford to play it down the middle,” Kahn said. “They’d look like Melba toast in an environment of olive bread and croissants if they did. They have to define their audience. One way to define your audience is by saying what you’re not. CNN has been saying, ‘We’re not like [Fox].’ ”

Fox media analyst Howard Kurtz said he believes CNN has become more opinionated since Trump took office.

“Sniping by rival cable news hosts is a more polarizing sport in the Trump era and that now includes CNN, which fairly or unfairly is often at odds with the president over its coverage,” said Kurtz, who formerly worked at The Washington Post and CNN. “I get why anti-Trump voices at other outlets try to lump Fox’s opinion hosts in with its news division to make it appear there’s one company line, which is clearly not true.”

Kurtz and guests on his Sunday program, “MediaBuzz,” often frame discussions of media coverage through CNN’s take on events. On his program last Sunday, Kurtz noted a CNN tweet reporting the names of 71 Republican lawmakers in Florida who had “refused” to vote for an assault weapons ban. “Does that sound like activism to you?” he asked a guest.

Kurtz says that he is equally tough on both networks.

“I make it my business to report fairly on CNN, criticizing or defending as the situation warrants. I treat Fox the same way, which is the ultimate test of fair media reporting.”

On his weekly media-review show, “Reliable Sources,” CNN host Brian Stelter often uses Fox as Exhibit A for what he has called the “upside down” reporting and commentary in the pro-Trump media. The topic has been featured on nine of his past 10 episodes.

After House Intelligence Committee Chairman Devin Nunes (R-Calif.) on Feb. 2 released his memo criticizing the FBI’s handling of the Russia investigation, for example, Stelter opined that the “pro-Trump media led by [Fox’s Sean] Hannity has circled the wagons around President Trump. They’ve distracted people about the truth involving Trump’s Russia ties, and they’ve done everything possible to destroy faith in Robert Mueller III’s probe.”

In an interview, Stelter said the intense scrutiny of Fox is justified by Fox’s relationship with Trump and the network’s impact on the “ecosystem” of conservative media outlets. “Fox influences the president of the United States in a way not seen by any other network,” he said. “Fox affects society in more ways than it did even three years ago. . . . If you only looked at CNN, MSNBC or CBS and you didn’t acknowledge Fox’s influence on the president, then you’d be missing the story.”

He added that the “reality is Fox’s ratings make it a skyscraper next to [conservative media]. Fox’s shadow is enormous.”

In fact, Fox’s average daily rating (1.55 million viewers) was more than twice CNN’s (700,000) throughout the day, according to Nielsen figures for February. CNN is in third place among cable news networks; MSNBC (with a daily average of 989,000) ranks second.

But USC’s Kahn said that MSNBC — whose prime-time schedule is chocka­block with overtly liberal opinion — is a less valuable target for Fox than CNN.

“CNN doesn’t cop to being lefty,” he said. “By beating up on CNN, you get to smear the entire mainstream media. It allows [conservative viewers] to doubt everything the mainstream media reports.”