Shortly before Fox News C.E.O. Roger Ailes was fired, in July 2016, after dozens of women accused him of sexual harassment, he delivered a warning to his boss, Rupert Murdoch. “Trump gets great ratings, but if you’re not careful, he is going to end up totally controlling Fox News,” Ailes said, a source briefed on the conversation recently recalled. “Roger was highly annoyed with Trump. He couldn’t contain him at all,” a high-level Fox staffer remembered.

But now there’s a new boss in charge—sort of. His name is Lachlan Murdoch. In May, Rupert named Lachlan, his elder son, chairman and C.E.O. of “New Fox,” the slimmed-down parent company that will emerge out of the Murdochs’ $71 billion deal to sell most of their entertainment assets to Disney. Lachlan, 47, is the heir that Rupert most wanted to succeed him even though, of the candidates in the family, Lachlan seemed to want the job least. He’s never been a political junkie like his father, an overt careerist like younger brother James, or a rebellious entrepreneur like older sister Liz. In 2005, Lachlan famously walked away from the company after clashing with Ailes and former C.O.O. Peter Chernin and moved back to the family’s native Australia.

Having returned to the fold, Lachlan has so far been content to be a caretaker rather than an empire builder. Although his nameplate was installed on an office at Fox News several months ago, Lachlan, who ran the New York Post in the 1990s, mostly is an absentee manager, choosing instead to work from the company’s Los Angeles office. When he occasionally drops in on Fox’s morning editorial meeting, he doesn’t cut a big presence. “He’s polite and asks questions about the news. He’s respectful and comes off as someone trying to learn,” one attendee said. In fact, Lachlan’s highest-profile decision was to hire Donald Trump’s former communications director, Hope Hicks, to be New Fox’s spokesperson. He didn’t know Hicks well—they had met only a handful of times—but he was encouraged by Trump and Jared Kushner to hire her. “It seems like he was doing Trump a favor,” one Fox journalist said.

With Lachlan content to let the Fox News machine run, the hand on the wheel belongs to Fox News C.E.O. Suzanne Scott. Scott’s management style is to effectively let the network’s producers run their shows independently. “No one is in charge,” a former executive told me. Without clear direction from the top, it’s every man for himself.

Fox’s hugely successful alliance with Trump has amplified divisions and rivalries among Fox’s on-air talent. Shepard Smith has emerged as the network’s most visible capital-J journalist and quasi-ombudsman. He’s used his three P.M. newscast to debunk Trump conspiracies, like the Uranium One obsession, and give airtime to investigative stories such as The New York Times’s 14,000-word exposé on Trump’s alleged tax dodging. Sean Hannity has called Smith “clueless” and “so anti-Trump.” At Mar-a-Lago in April, Hannity was overheard trashing Smith to Trump, according to one person familiar with the conversation. “Hannity was denouncing Shep, and Trump was eating it up.” (Hannity denied making the remarks.) Behind the scenes, Smith has taken on a bigger role in shaping Fox’s news coverage and critiques stories he doesn’t like, something that’s rankled some executives. “He’s the one who’s power hungry. He’s trying to pull the place left,” one former executive said. (A Fox News spokesperson disputes this.) Access to Trump also stokes jealousies among hosts. Sources say business anchor Neil Cavuto has complained to colleagues about Lou Dobbs’s closeness with the president. (A Fox News spokesperson says this is “not true.”)

Trump’s dominance of Fox is partly an accident, as a result of the lack of strong internal leadership. And, of course, in ratings terms, it’s been a happy accident. But the outcome is precisely the one Ailes had warned against: the network’s identity is now inseparable from that of the president, a development that would have surely horrified Ailes. Ailes may have been a right-winger, but he was sophisticated enough to know that Fox needed enough plausible distance from the subjects it covers to maintain the fiction of being “Fair & Balanced.” Now Fox is effectively an arm of the White House. Trump derives “policy” ideas from segments he likes and counts Sean Hannity as one of his closest advisers. The administration can feel like a Fox greenroom on a heavy news day. John Bolton serves as Trump’s national-security adviser; former Fox contributor Ben Carson runs HUD; former Fox & Friends newsreader Heather Nauert serves as State Department spokesperson; and former Fox president Bill Shine is deputy chief of staff for communications. (Hannity lobbied for him to get the job.) Fox military analyst General Jack Keane has been discussed inside the West Wing as a successor to Defense Secretary Jim Mattis, a former White House official said. One Fox personality literally got into bed with the Trumps: former The Five co-host Kimberly Guilfoyle is dating Don junior.