Fox News Channel anchor Shepard Smith. (Alex Kroke/Fox News)

Once again, Shepard Smith is doing cleanup on aisle Fox.

Moments after President Trump suggested on Friday that Fox News commentator Andrew Napolitano had validated the unfounded claim that President Barack Obama had recruited British agents to bug Trump Tower during the campaign, Smith stepped in to say otherwise. “Fox News cannot confirm Judge Napolitano’s commentary,” said Smith, the network’s chief news anchor. “Fox News knows of no evidence of any kind that the now-president of the United States was surveilled at any time, in any way.”

And perhaps to drive home the point, Smith added, “Full stop.”

It was a rare bit of record-correcting for Fox, which enabled Napolitano to pass off his wiretapping thesis for several days before British officials complained that it was rubbish. (As a result of Napolitano’s faulty reporting, Fox pulled him from the air for an indefinite period this week.) And it was perhaps no coincidence that the correcting came from Smith, whose off-message comments about Trump have made him an apostate to the conservative Fox News orthodoxy.

(Deirdra O'Regan,Thomas Johnson/The Washington Post)

Smith, for example, opened the same afternoon newscast Friday with a sly aside about Trump’s claims: “Of course, the president could learn firsthand whether the building in which he [lived] was wiretapped. All he’d have to do is ask the intelligence services. They work for him.”

Not blunt enough? In mid-February, following Trump’s freewheeling news conference, Smith labeled Trump’s responses “absolutely crazy.” He even — horror of horrors! — defended CNN, Fox’s mortal enemy, when Trump blasted it as “fake news” during another news conference. “CNN’s reporting was not fake news,” Smith said. “Its journalists follow the same standards to which other news organizations, including Fox News, adhere.”

Smith’s persistent fact-mongering has made him persona non grata among some parts of the Fox News faithful, in an echo of the hostile reaction to then-Fox anchor Megyn Kelly’s tough questioning of Trump during the campaign. For weeks, Fox fans have stormed social media with demands for Smith’s firing and boycott threats if the network doesn’t get rid of him.

Shep Smith has gone full Rachel Maddow,” ranted Paul Joseph Watson, contributing editor of the conspiratorial Infowars, on Twitter after Friday’s dunking of Napolitano. “MSNBC irrelevance is his calling.”

Some have posted an unflattering photo of Smith, 53, above the caption, “If you’re sick of this guy spewing his liberal tripe and his constant criticism of President Trump on a supposed news show, let Fox News know!!” It includes a number for Fox’s viewer comment line.

They’ve memed him, too. One depicts Smith wearing one of the pink wool hats that became the symbol of the Women’s March in January.

The mini-hysteria grew so loud earlier this month that a hoax website reported that Rupert Murdoch, Fox News chairman, had fired Smith for being “too controversial.” It was fake news, of course, but so widely disseminated that stepped in to debunk it.

The hubbub around Smith, who also is Fox’s managing editor of breaking news, has drawn silence from Fox. After initially being open to Smith speaking for a Washington Post article, the network declined to offer him for comment. Smith himself did not reply to interview requests sent to his work and personal email accounts.

Two people at rival networks say Smith is a short-timer at Fox and thus is feeling free to speak his mind on air. But that may be more rumor than fact; Smith has been at Fox since the network began in 1996 and has stayed on through multiple management changes, most notably the ouster last summer of co-founder Roger Ailes, whom Smith said he loved “like a father.”

The counter-theory is that Fox has purposely loosened its leash on Smith to carve out a modicum of independence from Trump.

“If I’m Fox News, I would view [Smith’s commentary] as a good thing right now,” said Dan Cassino, a political-science professor at Fairleigh Dickinson University. “It builds the credibility of a news organization,” a goal of Murdoch and his sons, James and Lachlan, who now run Fox’s parent company.

Besides, the network is at little risk of losing viewers because of Smith, said Cassino, the author of “Fox News and American Politics,” given that there are few cable news alternatives for conservatives. “Where would they go? They’re not going to watch One America Network [a small competitor]. Fox isn’t worried about its ratings.”

However, Tim Graham, director of media analysis for the conservative Media Research Center, buys the buzz that Smith is ready to bolt: “His aggressive defense of the liberal media suggests he’s looking at Greta Van Susteren and saying, ‘Yeah, I could do that.’ ” Van Susteren left Fox last summer and joined MSNBC.

Added Graham: “To me, it sounds like he’s advertising to other networks. It just seems bizarre for him to be sticking up for CNN and MSNBC. It’s like Jif peanut butter taking an ad sticking up for Skippy.”

In fact, David Shepard Smith Jr. has flashed his independent streak before, often diverging from the network’s playbook and occasionally inciting outrage from viewers.

When Obama declared his support for same-sex marriage during the 2012 campaign, Smith, who has been out about his sexuality, said on air that the president was “now in the 21st century.”

Amid the Baltimore riots of 2015, he scolded the hosts of the Fox discussion program “The Five” for blaming perpetrators’ actions on absent or indifferent parents. (“We don’t know whose fault it is,” he said.)

That same year, he asserted that human activity was responsible for climate change and compared the studies cherry-picked by “climate-change deniers” to those of the tobacco industry to play down carcinogens in cigarettes.

Perhaps most strikingly, he has generally declined to buy into Trump’s demonization of Muslims in the wake of terrorist attacks. “In the face of terror, will we panic or be calm and deliberative in approach?” he asked after the attacks in Paris in late 2015. “Confronted with those who want to change our way of life, will we abandon our freedoms and the rights granted to us by the Creator, or will we welcome huddled masses yearning to breathe free?”

Unlike Kelly, who endured a drumbeat of attacks from Trump, Smith has largely escaped Trump’s wrath. Trump has tweeted criticism of him just once, during the campaign in 2015: “Boy is this guy @ShepNewsTeam tough on me. So totally biased. As a reporter, he should be ashamed of himself!

Maybe he hasn’t been watching Smith lately.