It was Saturday night, and Sean Hannity found himself at a Rascal Flatts concert.

But the Fox News host did not appear to be paying too much attention to the performance taking place onstage. Instead, he found himself staring into the glow of his iPhone, furiously tweeting at Rich Lowry, the editor of National Review.

"NRO ESTABLISHMENT AND WORSE. WHO DID U WANT? Jeb?? NRO=HRC. Who will NRO endorse?OWN IT RICH! Lol," Hannity tweeted at 9:54 p.m. ET.

"NRO FOR HILLARY ONLINE!!" Hannity wrote in a follow-up tweet moments later.

It was the first time Hannity had sparred with his critics while enjoying such hits as "What Hurts the Most." But for months, the Fox News host has faced the brunt of criticism from conservatives upset about Donald Trump's ascension within the Republican Party.

As the host of one of the top radio shows in the country and with a prime-time television slot on Fox News, Hannity was easily the most visible member of the Trump-boosting media, making him a popular target.

Conservatives have publicly and privately trashed him for supporting the New York billionaire, something they have argued required him to betray the very principles he had for years vowed to protect. More and more, he has found himself on something of an island, punching back at critics who say he has made a colossal mistake.

And in recent weeks, the conservative talk-show host seemed to have had enough, not only moving to declare war on the Never Trump faction of the conservative news movement but also deciding to do so in a scorched-earth manner.

"Months before a single vote was cast, Sean threw his full support, on both his television and radio programs, behind the most liberal candidate in a field of 17 Republicans," John Ekdahl of the popular conservative Ace of Spades blog said Monday. "Ultimately, he realizes this was a gigantic mistake, and now he's attacking those who continue to point it out."

The radio host launched a war of words on several prominent conservative voices last month and, in an extended tirade, told his millions of listeners that he would hold those who refuse to back Trump responsible for Hillary Clinton's policies should she win in November.

"You own Hillary Clinton," Hannity said. "National Review, you own it. Glenn Beck, you own it. Ted Cruz, you own it ... She wins, I'm blaming all of you. You own all of her policies."

That was only the beginning.

Though Hannity vowed to stop wasting his breath on the Never Trump movement, he has regularly returned to the topic, breathing fire on its members on a regular basis over the past several weeks.

"Hannity is absolutely out of control and fighting for his life as a person of standing," Erik Wemple, a media critic at The Washington Post, recently told Business Insider. "His embrace of Trump is devoid of principle and reason and integrity, and he has reached the desperate point of lashing out at everyone to boost his own reputation."

Sean Hannity during a 2014 segment. Paul Zimmerman/Getty Images

Hannity has characterized some of the most prominent names in the conservative media movement as "arrogant," "stubborn," and "stupid" people who are "purposefully distorting" and "creating doubt" about Trump's record.

During his Saturday-night Twitter tirade, the radio host accused Lowry of being a liar. He tossed acid on Bill Kristol, the Weekly Standard editor, mocking the size of Kristol's following on Twitter in an effort to dismiss him as irrelevant. And he characterized National Review, perhaps the most respected conservative publication in the US, as "elitist BS."

"Hannity is picking fights publicly because that's what he thinks his audience wants," Stephen Miller, the publisher of the Wilderness blog and a former contributor to National Review, told Business Insider.

For the most part, Hannity's promise to hold Never Trump forces responsible for a Clinton White House has been dismissed as an empty threat.

National Review columnist Jonah Goldberg and Kristol have joked about it on Twitter:

And Pat Gray, the cohost of "The Glenn Beck Program," asked on Facebook, "Who does this guy think he is, Heinrich Himmler?" He was referring to the high-ranking official in Nazi Germany. (Full disclosure: I previously worked for TheBlaze, a property owned by Beck.)

"This is like the last section of 'Revenge of the Sith,' where Anakin's eyes start turning bright red," Gray wrote of Hannity's recent behavior, referring to the "Star Wars" film.

Gray added in another note: "What will being held 'accountable' by Sean Hannity entail, I wonder? No free tickets to ride on the 'Stop Hillary Express 2016?' Will he not call on us for questions when he's Trump's Press Secretary? I shudder to think."

But the attacks from Hannity have deepened an already-existing rift inside conservative media. Moreover, it has risked creating an irreparable divide — something Glenn Beck, one of the country's top conservative voices, has cautioned against.

"If Hillary Clinton wins, if we don't reunite with everyone and have all hands on deck, there's no chance of stopping Hillary Clinton. Zero," Beck said on his radio program. "So do not divide anymore. Please. Don't divide anymore."

Thus far, however, Hannity — who declined to comment for this story — has not heeded such advice. He appeared to mock Beck's call for unity on his radio program and has showed no signs of ceasing his war on the Never Trump movement.

It appears, at least for now, that Hannity seems to think he can punch his way out of his jam.