After Mr. Trump went kicking and screaming from the White House (as well as from Twitter and Facebook), Mr. Carlson, still ensconced on Fox News and with unfettered access to social media, emerged as the far right’s standard-bearer in America’s culture wars, coming to occupy the same mental real estate — among both conservatives and liberals — that Mr. Trump once did. He was no longer just a cable host but a movement leader — working to bring the G.O.P. in line with his own views. On his show, he boosted ideological comrades like J.D. Vance, who shared Mr. Carlson’s skepticism about U.S. support of Ukraine in its war with Russia, gifting Mr. Vance hours of free airtime in the run-up to the Republican primary for the 2022 Ohio Senate race. Off-air, he personally lobbied Mr. Trump to give Mr. Vance his endorsement. At one point Mr. Carlson spent nearly two hours on FaceTime with Mr. Trump, while Mr. Trump golfed in Florida, making the case that Mr. Vance believed what Mr. Trump believed and that, were Mr. Trump to run for president again, he needed someone like Mr. Vance in the Senate. According to a person familiar with the call, Mr. Trump ended it by telling Mr. Carlson, “You’ll be happy.” A few weeks later, Mr. Trump endorsed Mr. Vance, propelling him to the Republican nomination and, eventually, the Senate — one of the few 2022 bright spots for Republicans.

As Mr. Carlson turned his attention toward the 2024 presidential race, his relationship with Mr. Trump, once again, became complicated. On the one hand, he was dead-set opposed to Nikki Haley, for whom he’d developed an intense personal dislike during an ill-fated hunting weekend about 10 years ago. (After Ms. Haley eventually launched her presidential candidacy in February, Mr. Carlson told his viewers, “Nikki Haley believes in collective racial guilt,” before going on to say, “She believes identity politics is our future. ‘Vote for me because I’m a woman,’ she says. That’s her pitch.”) On the other hand, Mr. Carlson, like many at Fox News — including Mr. Murdoch, who, in the wake of Jan. 6, told a former executive that Fox was seeking “to make Trump a nonperson” — appeared to be leaning toward the Florida governor, Ron DeSantis, as a less erratic, more electable alternative to Mr. Trump. (In 2020, Mr. Carlson moved from Washington, D.C., to the small resort town of Boca Grande, Fla.)

Sensing this, Mr. Trump tried to win back Mr. Carlson, but Mr. Carlson refused a sit-down. Finally, last July, Donald Trump Jr., with whom Mr. Carlson has become close, traveled to Mr. Carlson’s summer residence in rural Maine. There, according to people familiar with the visit, Mr. Trump Jr. pressed Mr. Carlson to meet with his father. A few weeks later, Mr. Carlson showed up at Mr. Trump’s Bedminster resort in New Jersey on the same weekend it was hosting the Saudi-backed LIV Golf tour. The result was pictures of Mr. Carlson yukking it up with Mr. Trump and Marjorie Taylor Greene in the tournament’s V.I.P. section.