White House Press Secretary Jay Carney listens to media questions during his daily news briefing at the White House, Dec. 12, 2013, in Washington, D.C. (Carolyn Kaster/AP)

It doesn’t take long, or take very much, for the Jon and Jay show to get rolling at the daily briefing — the ritual meet-the-media sessions in the White House press room.

“But, Jay,” starts Jonathan Karl of ABC News last month, boring in to a statement from press secretary Jay Carney about the troubled rollout of the Affordable Care Act. “I want to go back to exactly what the president said.” Punching his words for emphasis, Karl pounded away: “He said you can bypass the Web site and apply by phone or in person, and it could be done in 25 minutes.”

An agitated Carney mimicked Karl’s tone in reply. “Jon, I get it,” he snarked, to a few nervous chuckles among the assembled reporters.

“Your mocking is entertaining,” Karl replied, “but the president said you can apply within 25 minutes [and] that’s not true.”

As Karl continued to press, Carney slapped him down. “You can have this soliloquy by yourself,” Carney said. “Jon, I think everybody else here understands what I’m saying. I’m sorry I can’t say the same for you.”

Jon Karl, ABC News’ chief White House correspondent. (Fred Watkins/ABC)

The usually unflappable Carney has bristled early and often of late at Karl’s frequently exasperated questions on various issues — the Affordable Care Act’s inception, the government shutdown, federal-worker furloughs. On one occasion, Karl got under Carney’s skin by interrupting him as he answered another reporter’s question. “Hey, Jon, I’m having a conversation here,” Carney shot back. Noting that the discussion involved House Speaker John A. Boehner (R-Ohio), Carney directed a barb at Karl: “I’m sure that you’ll represent what the speaker is saying in a minute.”

When Karl pressed Carney on the suspension of military death benefits during the shutdown, Carney snapped before catching himself: “If you want to editorialize. . .

Carney occasionally tangles with other reporters — among them, notably, Fox News’ Ed Henry — but his exchanges with Karl have been especially testy, raising eyebrows among the White House media cadre and threatening to become a sideshow of the televised daily briefings.

Is this just dramatic preening, staged for the C-SPAN viewing public? Or is there any larger import to these mini-clashes? Does rattling the White House’s official spokesman shed any additional light on the workings of presidential power?

Some of Karl’s fellow press-room denizens view the give-and-take skeptically. Asks one: “How much of [this] is aimed at breaking news by getting Carney to crack under pressure, and how much of it is pure theater aimed at ratings, impressing bosses or otherwise gaining attention?”

In an exchange of e-mails on the topic, Carney brushes off questions about his relationship with, and reaction to, Karl this way: “Answering tough questions is part of the job.” He declined to respond to follow-up questions.

Karl is more expansive. In an interview last week, he said there is a method to his approach. “I believe we have to be willing to ask tough questions but also not always be willing to accept a non-answer,” he said. “When the answer is not responsive, I think we have a duty to continue to push. I don’t see it as going in there to be confrontational [but] as being pretty insistent about getting straight answers.”

As for Carney’s pushback, Karl said: “I take none of it personally. We are in a pressure-filled environment where the stakes are high. Jay is a pro.”

As professional combatants go, Carney, 48, and Karl, 45, are a well-matched pair. Karl is a respected, veteran Washington journalist (he spent eight years at CNN before joining ABC in 2003), as was Carney when he left his post as Time’s Washington bureau chief to become Vice President Biden’s communications director in late 2008. The two men are physically so similar — mild-looking, sandy-haired, bespectacled — that they could be related.

In fact, outside the office, Karl says he and Carney are good friends; their relationship dates to the Bill Clinton era. Carney’s wife, Claire Shipman, is Karl’s colleague at ABC News; she covered the White House before her husband joined it. Among other things, the two men share an interest in Russian history and politics.

“I have enormous respect for Jay,” Karl said. “I think, in some ways, he’s one of the smartest people to hold that job. And I believe if he was sitting where I’m sitting, he’d be asking some of the same questions. I think he understands we have a job to do.”

Of course, being the toughest guy in the room can have its own payoff. ABC’s Sam Donaldson became a household name for his televised run-ins with White House officials, including his trademark act of shouting provocative (though rarely answered) questions at President Ronald Reagan. David Gregory, who barely contained his skepticism and impatience with a series of President George W. Bush-era press secretaries while NBC’s White House reporter, is now host of “Meet the Press.” And Karl’s immediate predecessor at ABC, Jake Tapper, went from the White House beat to his own daily show on CNN, “The Lead.” (Tapper calls Karl “tenacious and tough, qualities not always in abundance in D.C.”)

One of his network’s most visible faces, Karl says he harbors no immediate ambition at ABC beyond the White House beat. He doesn’t want for airtime, popping up often on “Good Morning America,” the evening newscast and “Nightline.” He’s also George Stephanopoulos’s substitute host on“This Week” on Sundays, a role that helped vault Tapper onto his CNN show.

Last May, Karl briefly found that he was the story after he reported that the White House had written 12 versions of its talking points about the terrorist attacks in Benghazi, Libya, last year. The story was a solid scoop, except for one element: Karl initially reported that he had “reviewed” internal e-mails sent by deputy national security adviser Ben Rhodes that suggested the revisions were being made at the behest of the State Department.

What Karl had obtained was a summary of the e-mail, apparently provided by Republican congressional sources seeking to discredit the administration. In a small irony, Tapper — Karl’s former colleague — broke the news about the e-mail’s contents, which made no mention of the State Department, contrary to Karl’s bombshell.

It was a rare stumble for Karl, and he’s chastened by it. “I’ll leave it at what I ended up saying at the time,” he said. “Unfortunately, one of those e-mails was not correct. As a reporter, you regret getting anything wrong.”

The larger question about Karl, Carney and the daily White House briefings is whether the sessions produce much beyond the occasional telegenic confrontation. Ron Fournier, who was the veteran White House correspondent for the Associated Press, says the daily briefings are somewhat valuable as a conduit for actual news but that they have become “a crutch” for reporters — a substitute for more energetic and probing reporting.

Fournier, now a columnist for the National Journal, traces the decline of the briefings to 1995, when Mike McCurry, press secretary for President Bill Clinton, permitted C-SPAN to televise them live. “It made it more of a show and less of a place to get and give information,” Fournier said. “We all know it’s being televised, and we all end up puffing out our chests and acting a bit. It’s human nature.”

According to statistics kept by Martha Joynt Kumar, a Towson University professor who studies the media and the White House, about two-thirds of every briefing is devoted to taking questions from reporters from the broadcast and cable news networks, the Associated Press and Reuters news services. The dominance of TV reporters during the briefings is no accident, she said: “The White House is most interested in TV and in getting their message out on television.”

That might explain some part of the Jon-and-Jay follies, but Karl says that the public benefits from the daily ritual, too. “Reporters can complain that the briefings aren’t very useful, but we would be the first to scream bloody murder if they went away,” he said. “That’s a very useful hour of the day. I think it’s important to understand what [the White House] is thinking, what their rationale is [and] what their response is to those who are criticizing them.”