Tucker Carlson had a problem.

After years in the cable wilderness, he had made a triumphant return to prime time. And his new show, “Tucker Carlson Tonight,” had leapfrogged to the heart of Fox News’s evening lineup just months after Donald J. Trump’s upset victory shattered the boundaries of conventional politics.

But as Mr. Trump thrashed through his first months in office, Mr. Carlson found himself with an unexpected programming challenge: Fox was too pro-Trump. The new president watched his favorite network religiously, and often tweeted about what he saw there, while Fox broadcasts reliably parroted White House messaging. No one was more on message than Sean Hannity, then Fox’s highest-rated star, who frequently devoted his show to Mr. Trump’s daily battles with Washington Democrats and the media.

Newly planted in Fox’s newly vacated 8 p.m. time slot — previously held by the disgraced star Bill O’Reilly — Mr. Carlson told friends and co-workers that he needed to find a way to reach the Trump faithful, but without imitating Mr. Hannity. He didn’t want to get sucked into apologizing for Mr. Trump every day, he told one colleague, because the fickle, undisciplined new president would constantly need apologizing for.

The solution would not just propel Mr. Carlson toward the summit of cable news. It would ultimately thrust him to the forefront of the nationalist forces reshaping American conservatism. “Tucker Carlson Tonight,” the host and his producers decided, would embrace Trumpism, not Mr. Trump. The show would grasp the emotional core of Mr. Trump’s allure — white panic over the country’s changing ethnic composition — while keeping a carefully measured distance from the president himself. For years, as his television career sputtered, Mr. Carlson had adopted increasingly catastrophic views of immigration and the country’s shifting demographics. Now, as Mr. Trump took unvarnished nativism from the right-wing fringe to the Oval Office, Mr. Carlson made it the centerpiece of “Tucker Carlson Tonight.”

He began seeking out stories, one friend observed, that were sometimes “really weird” and often inaccurate but tapped into viewers’ fears of a trampled-on American culture. He inveighed against Macy’s new line of hijabs, and devoted a segment to “Gypsy” refugees in a Pennsylvania town who Mr. Carlson said had left “streets covered — pardon us now, but it’s true — with human feces.” (It was not true: Local officials ultimately documented a single instance of a refugee child who had pulled down his pants outside because he couldn’t make it back home in time.) He cataloged, and magnified, overlooked instances of what he cast as growing discrimination against white Americans. Stories about the threat of immigration had long been a feature of Fox. But Mr. Carlson dialed up the intensity, expertly weaving tropes borrowed from the far right into a narrative that would come to define “Tucker Carlson Tonight”: falling birthrates among the native-born, big-city crime, lax immigration policies designed to forcibly alter American society — all engineered or encouraged by a “ruling class” desperate to censor public discussion of its own failures.

Mr. Carlson’s darkening arc foreshadowed a transformation beginning to sweep through Fox itself. As Mr. Trump fought to build a border wall and keep Muslims out of the United States, Fox’s journalists and right-wing commentators would clash repeatedly over what many longtime staff members saw as a creeping invasion of the news divisions by allies and functionaries of the higher-rated, pro-Trump prime-time hosts. Mr. Carlson would be both instigator and beneficiary of Fox’s civil war. He forged a relationship with Lachlan Murdoch, the Murdoch family’s heir apparent, who would become his most public supporter at Fox. And while Mr. Murdoch and Fox executives have often couched their defense of “Tucker Carlson Tonight” as a protection of free inquiry and controversial opinions, the reality is less high-minded. From the beginning, Mr. Carlson’s on-air provocations have been part of a painstaking, data-driven campaign to build and hold Fox’s audience, according to former Fox executives and employees — an experiment that has succeeded wildly in bolstering Mr. Murdoch’s profit machine against the long-term decline in cable news subscriptions.

The network’s leadership takes a broader view of Fox’s financial and ratings success. A spokeswoman for the network provided the following statement: “Fox News Media has grown through strategic innovation, redirecting investments in journalism to encompass more than 50 percent of the budget while expanding our footprint beyond one legacy linear network to eight thriving platforms. As a result, we’ve doubled our audience, achieved unrivaled results, and have become the destination that more Democrats and independents choose for their news coverage, while our competitors have lost dramatic levels of viewership. We couldn’t be prouder of our entire team, whose commitment to excellence in journalism and opinion has led Fox News Media to all-time ratings records and delivered the best in class to our viewers.”

Mr. Carlson declined to be interviewed for this article. At Fox, his popularity with viewers has allowed him to fend off external critics and shut down those within, from news anchors to junior employees who objected to his rhetoric. His importance to the Murdochs has grown along with his ratings, giving him unusual power at the network. During the waning months of Mr. Trump’s presidency, Mr. Carlson would harness the tidal wave of white resentment animated by Mr. Trump to draw the largest audience of any show on television.

Today, Mr. Carlson’s influence reaches far beyond the channel he works for, or the audience that tunes in to his show. Mr. Trump is out of office and banned or suspended from the leading social media platforms. But Mr. Carlson remains, both high priest and champion of Mr. Trump’s most ardent followers. Each night, Mr. Carlson channels the passions and grievances that have replaced the Reagan-era conservatism he grew up on, from the tyranny of mask mandates to the grave danger posed by critical race theory in schools. He has aggressively defended the insurrectionists who stormed the Capitol on Jan. 6 — an attack that Mr. Carlson, borrowing the former president’s “deep state” canards, has portrayed as a false-flag operation masterminded by the Federal Bureau of Investigation. Ambitious Republican lawmakers now echo his embrace of the “great replacement” conspiracy theory, once relegated to the far-right fringe, that Western elites are importing immigrants to disempower the native-born.

In some respects, Mr. Carlson has taken Trumpism away from Mr. Trump. While the former president has urged his followers to get vaccinated and sought to claim more credit for his administration’s efforts to fight Covid-19, Mr. Carlson has continued to promote doubt about the vaccines’ efficacy, even likening mandates to Nazi medical experiments. On the Jan. 6 anniversary, Senator Ted Cruz, the Texas Republican, set out to walk back his comments accurately calling the Trump-inspired riot a “violent terrorist attack.” He didn’t apologize to Mr. Trump. He apologized to Mr. Carlson, in a cringing appearance on “Tucker Carlson Tonight.”

Trumpism Without Trump

“Tucker Carlson Tonight” was at first only a slight update on the classic cable shoutfest. The show arrived on Fox a few months after Roger Ailes, the network’s powerful co-founder, was forced out amid a widening sexual harassment scandal. Mr. Ailes had been lukewarm on Mr. Carlson, then paying his dues on the weekend edition of “Fox and Friends.” (According to a Fox colleague at the time, Mr. Ailes had once described Mr. Carlson’s hiring at Fox as “his last chance” in cable news.) But the Murdochs liked him, and Rupert Murdoch, who temporarily took the reins after ousting Mr. Ailes, installed Mr. Carlson in Fox’s 7 p.m. slot.

In segments dubbed “Tucker Takes On,” Mr. Carlson would invite on a liberal foil for combat, an approach Fox executives sometimes referred to as “Twitter for television.” There were lighter segments, like “The Friend Zone,” in which the host would bring on a Fox colleague or friend for a bit of self-promotion, or “King for a Day,” in which viewers would be invited to propose one thing they would do to fix the country.

Less than two months in, Mr. Murdoch promoted Mr. Carlson again, to the higher-profile 9 p.m. slot abruptly vacated by Megyn Kelly. To help write scripts, Mr. Carlson hired one of his old Daily Caller reporters: Blake Neff, a young South Dakotan who would later be outed by CNN, and then let go, for posting racist and sexist jokes on the internet. “Tucker Carlson Tonight” began to dial up coverage of college liberals, both a Fox staple and Mr. Neff’s specialty at The Caller. Sometimes titled “Campus Craziness,” the segments featured conservative professors shunned for criticizing Islam and left-wing professors expressing hatred for white people. One episode mocked students in Mississippi who mistook a stray banana peel for a hate crime. Mr. Carlson’s ratings shot up, and just a few months later, in April 2017, Mr. Murdoch promoted him to succeed Mr. O’Reilly, long Fox’s most prominent and popular host. Mr. Carlson’s agents immediately began shopping a book, with a price tag said to be as high as $15 million.

THE CARAVAN

To help redesign “Tucker Carlson Tonight” for the 8 p.m. hour, Fox assigned Ron Mitchell, a former O’Reilly producer recently promoted to Fox’s executive ranks, where he would supervise “story development” across prime time. Fox had always excelled not just at attracting more viewers than its rivals but at getting them to stick around longer, giving an added bump to its Nielsen ratings. To maintain its dominance in the post-Ailes era, the teams working on Fox’s evening lineup began to make wider use of expensive ratings data known as “minute-by-minutes.” Unlike the “quarter-hour” ratings more commonly used in cable newsrooms, which show how each 15-minute “block” performed, the minute-by-minutes allow producers to scrutinize an audience’s real-time ebb and flow. Mr. Carlson, determined to avoid his fate at CNN and MSNBC, was among the network’s most avid consumers of minute-by-minutes, according to three former Fox employees.

His new direction — Trumpism without Trump — took shape that summer. The lighter segments faded from view. Notably, Mr. Trump was mentioned less often than on “Hannity,” and Mr. Carlson sometimes even criticized the president, particularly when he deviated from campaign promises like building the border wall and avoiding what he had once called “stupid” wars. In private, Mr. Carlson mocked the president’s habit of calling to head off his on-air attacks. (When Mr. Trump called to pre-empt criticism of one foreign-policy move, Mr. Carlson declined the call, according to a former Fox employee who witnessed it.)

Most strikingly, “Tucker Carlson Tonight” began devoting more and more airtime to immigration and to what its host depicted as the looming catastrophe of demographic change. “He is going to double down on the white nationalism because the minute-by-minutes show that the audience eats it up,” said another former Fox employee, who worked frequently with Mr. Carlson.

He covered protesters’ attempts to pull down Confederate monuments with hyperbolic intensity; one such episode, he told his viewers, marked the beginning of “the destruction of America’s delicate social fabric.” His producers scavenged local news for under-covered items about refugees and migrants, which Mr. Carlson blew up into national news. He also began to venture farther afield than other hosts. He mocked Austria as the soon-to-be “caliphate of West Arabia.” The immigration backlash and migrant crimes in countries like Sweden and Germany became forewarnings of America’s future. “The country’s in decline,” he told viewers in the fall of 2017. He added: “Everyone knows that. It’s not racist to note that.”

A Ratings Game

But as America declined on screen, Mr. Carlson ascended behind it.

Fox News was undergoing the most significant changes in its history, a shift that would position Mr. Carlson to seize outsize power within the network. The Murdochs were negotiating to sell most of their television and studio assets to the Walt Disney Company, a transaction that would also resolve the family’s succession battle, leaving Lachlan Murdoch as sole heir to the throne. He was widely viewed as having more conservative politics than his father. In Australia, he had been instrumental in installing a slew of hard-right executives and editors at the family’s media properties, while overseeing efforts to transform the little-watched cable channel Sky News into a mini-Fox, with a fiery evening lineup. At Fox, he became friendly with Mr. Carlson, who cultivated a perception within the network that the two men were close.

Mr. Murdoch ran the new Fox enterprises — now a stripped-down company with Fox News at its core — from across the country, in Los Angeles. (Last year, he moved back to Australia.) In mid-2018, he announced the appointment of Suzanne Scott, an Ailes-era network veteran, as the new Fox News chief executive. Though credited with helping revamp the network’s post-O’Reilly lineup, Ms. Scott, who would preside over Fox expansions into weather, books and other new divisions, seemed disinclined to exert Mr. Ailes’s tight rein over Fox’s talent, according to former employees. And where Mr. Ailes had been regarded within Fox — if not always outside it — as protective of the news divisions’ credibility, Ms. Scott, mindful of the cable industry’s long-term headwinds, was focused on preserving the network’s audience. “Suzanne began talking about, ‘We have to do more of what we do best,’” said one former senior employee.

Under Ms. Scott, Fox’s news shows began to more closely mimic its highly rated prime-time opinion shows in both tone and topic. Guests brought on to analyze the day’s stories would instead find themselves asked to respond to clips of provocative comments made by Mr. Carlson and other hosts or guests the night before — a backdoor way for Fox to inject prime-time material into the lower-rated dayside shows. In 2018, after a former Hannity producer took over the network’s widely read website, FoxNews.com, he assembled a team of reporters called Fox News Flash, who were deployed to write news stories built solely around video clips from prime time. Mr. Carlson’s drove the most traffic, according to a former FoxNews.com employee.

One major force behind the news-side changes was a former Megyn Kelly producer named Tom Lowell, a Fox vice president who assumed growing authority over the network’s correspondents and news coverage. He was considered a favorite of the elder Mr. Murdoch, who appreciated his tabloidy approach to news curation. He was less popular among his subordinates, who nicknamed him “the burglar,” on account of his reputation for stealing credit for ideas, and because of a long-ago incident that became Fox lore as he rose: In his 20s, Mr. Lowell and two friends were arrested after breaking into a liquor store in Florida. (Mr. Lowell received three years’ probation, according to public records.) One week, while an executive who typically ran the high-level daily news meeting was on vacation, Mr. Lowell took over the role and never gave it back.

He encouraged shows to focus on the kind of grabby, inflammatory stories that dominated prime time and drove ratings. As the midterm elections approached and Mr. Trump’s unpopularity threatened to sink down-ballot Republicans, Fox began nonstop coverage of a migrant caravan wending its way through Central America to the U.S. border. Mr. Carlson and other prime-time hosts and guests called the caravan — mostly women and children — an “invasion” dozens of times in the weeks before the election, according to tallies by Media Matters and CNN. They continued to do so even after a man walked into a Pittsburgh synagogue in late October and murdered 11 people, leaving behind a trail of social media posts railing against immigrants and Jews and applauding how people were now calling illegal immigrants “invaders.”

Shortly after the attack, the longtime anchor Shepard Smith, a beloved figure in the Fox newsroom, threw a brushback pitch at his own network. “There is no invasion,” he told viewers of his afternoon news show. “No one’s coming to get you.” Whether or not the caravan threatened America, however, it was a boon to Fox: That October, ratings were even higher than they had been right before the 2016 presidential election. Network executives soon began retooling the dayside shows, applying the approach that had worked for Mr. Carlson and his prime-time colleagues. Mr. Mitchell, now promoted to a high-level position running “analytics” across Fox, began sitting in on story meetings to vet topics and guests, a role that discomfited some reporters and producers. He handed out color-coded bar charts detailing the minute-by-minute performance of each show. “They’re all obsessed with the minute-by-minutes,” said a former Fox employee. “Every second that goes on that network now gets scrutinized.”

Mr. Lowell and Mr. Mitchell pitched the initiative as “Moneyball” for television: a data-driven, audience-first approach to deciding what to cover and how to cover it. But journalists on the daytime lineup discerned a pattern to what the audience didn’t like. Segments featuring Fox’s own reporters consistently drew lower ratings, especially if they were covering stories the audience deemed unfavorable to Mr. Trump. So did guests who leaned left, or simply staked out independent viewpoints. Mr. Lowell and Mr. Mitchell, for example, urged shows not to book Chris Stirewalt, a respected, down-the-middle political editor and analyst. But immigration was a hit. Coverage of migrant caravans became a Fox mainstay, with one correspondent even embedded with refugee groups.

Fox executives wanted to focus on “the grievance, the stuff that would get people boiled up,” said one current Fox employee. “They’re coming for you, the Blacks are coming for you, the Mexicans are coming for you.”

Dangers Abroad

In the spring of 2018, Mr. Carlson aired a segment that jolted even his more jaded Fox colleagues. South Africa’s white farmers were “being targeted in a wave of barbaric and horrifying murders,” he told viewers. The Black-led government “just passed a law allowing it to seize their farms without any compensation, based purely on their ethnicity.”

Until Mr. Carlson waded in, few Americans were paying attention to “farm murders” in South Africa. In a country of 60 million people, where violent crime is common but the vast majority of its victims are Black, the police record dozens of murders of whites on farms and other small holdings each year. But the notion that white farmers were being singled out for attack was largely confined to the far-right web, where writers and commenters warned of a burgeoning “white genocide” — itself a neo-Nazi trope dating back to the end of apartheid.

Then the Murdoch empire stepped in. In the winter of 2018, reporters for a Murdoch-owned Australian tabloid, The Daily Telegraph, contacted AfriForum, a self-styled civil rights group for South Africa’s Afrikaner white minority. For months, with little success, the group had been circulating widely contested studies claiming to show that white farmers faced a disproportionate risk of murder and brutalization. After touring white-owned farms in South Africa, the Telegraph team returned with a package of columns and news articles asserting that being a South African farmer was “now the world’s most dangerous job” and demanding that they be granted emergency refugee visas. From there, the story would be picked up by the Fox-inspired nighttime hosts on Sky News. Within days, Australia’s home affairs minister floated the idea of fast-track visas for South African farmers.

The idea went nowhere, but the story soon jumped around the world. In a 2018 meeting of Fox News executives, according to two people with knowledge of the discussions, Mr. Lowell proposed covering farm murders for American audiences, echoing the fevered framing of his Australian colleagues: a country descending into chaos, an impoverished Black majority scheming to kill white farmers and steal their land. Mr. Carlson, it turned out, was also pursing the story. He had briefly mentioned farm murders in a segment that March, and two months later, when AfriForum officials made a lobbying trip to Washington, an ally put them in touch with him.

“My understanding was, he was interested in the topic already, and someone we had gotten to know over time recommended he speak with us,” said Ernest Roets, AfriForum’s deputy chief executive, who declined to identify the intermediary.

AfriForum formally rejects the far-right idea of a “white genocide.” But when he interviewed Mr. Roets on his show that May, Mr. Carlson bulldozed through the group’s careful caveats, describing “in some sense an intentional campaign,” supported by the government, “to crush a racial minority within your country.”

In an interview with The New York Times, Mr. Roets acknowledged that Mr. Carlson had exaggerated.

“It’s not my job, as a spokesperson, to tell a journalist how he or she should frame a question,” he said. “I would be a bad spokesperson to use what little time I have to say, ‘Well, let’s frame that question a little differently.’”

SOUTH AFRICA

Mr. Carlson’s coverage sparked a rare high-level dispute inside the network. During a subsequent meeting of Fox’s senior executives, Brian Jones, president of Fox Business Network and the highest-ranking Black man in Fox leadership, explained that almost everything Mr. Carlson was saying on the air was wrong. Legislators in South Africa, where whites still own the majority of private farmland, had begun debating a constitutional amendment to allow uncompensated land seizures, but no such measure had been passed. Though intended to reverse apartheid-era land dispossession, the proposed amendment did not target farmers on the basis of their race or ethnicity. Nor had the government backed a campaign of ethnic violence and murder. Mr. Jones told his fellow executives that Mr. Carlson’s coverage had been ripped from far-right sites, including the neo-Nazi Daily Stormer, according to a person with knowledge of the discussions. (Mr. Jones, who left the network in 2019, did not respond to a request for comment.)

Mr. Lowell defended the segments, and Mr. Jones was ultimately overruled. A Fox spokeswoman disputed that account, saying that Mr. Lowell had only pushed for the story to be investigated to see if it was accurate. But word of the high-level editorial dispute soon filtered down through the network. Even among the generally right-of-center rank-and-file, discontent was growing over Fox’s nativist tilt and racial scaremongering. Now staff members who had watched the farm-murder story swirl around far-right websites wondered how it had arrived at their network, and why Mr. Lowell and Mr. Carlson had pushed it, especially when Fox was so busy covering Trump-related breaking news and more conventional controversies.

But Mr. Carlson dug in. He covered South African farm murders and land disputes throughout the spring and summer, again claiming that officials there were seizing land that they hadn’t under a constitutional amendment that didn’t exist. That August, after an episode of “Tucker Carlson Tonight,” President Trump tweeted that his administration would “closely study” the seizure of white-owned land and the “large-scale killing of farmers.” Alt-right and neo-Nazi figures in the United States cheered the propaganda coup. Patrick Casey, leader of the group Identity Evropa, exulted that Mr. Trump’s proclamation could help bring white nationalist ideas to a mainstream audience.

“Conservatives becoming aware of the plight of White South Africans has the potential to take them beyond the current limitations of ‘acceptable’ conservative immigration debate toward identitarianism,” Mr. Casey tweeted.

Strange Bedfellows

Fox journalists soon had another reason for concern. Around the same time Mr. Carlson was promoting the notion of a South African ethnic cleansing, Fox was lurching through a post-Ailes rebuilding of its human resources organization. Lines of authority and power had always been mysterious at Fox, and so when a formal organizational chart appeared on the company’s employee portal, some curious employees logged on to see who reported directly to Rupert Murdoch.

Most of Murdoch’s subordinates were unsurprising, according to several people who viewed the chart. But one came as a shock: Peter Brimelow, founder of the website VDare.

The British-born Mr. Brimelow had known Mr. Murdoch for decades and once worked as a columnist for MarketWatch, the Murdoch-owned financial news site. But over the years, he had adopted more pronounced nativist views; VDare, started in 1999, had evolved into a hub of the new, more online-oriented white nationalist movement. Mr. Brimelow once described the Obama administration as a “Minority Occupation Government” and California as “totally overrun by barrios of illegal immigrants.” Shortly after Mr. Trump was elected, he spoke at a conference held by the National Policy Institute, a latter-day white nationalist group. (Mr. Brimelow sued The Times in 2020 for articles in which either he or VDare was described as white nationalist; a judge dismissed the case later that year. A separate lawsuit brought by VDare is still pending.)

Mr. Brimelow’s apparent role at Fox set off a new wave of consternation and gossip. Employees who asked about the relationship were given a variety of explanations. Mr. Brimelow was said to be helping with Mr. Murdoch’s memoirs — a project that, as far as most people understood, their boss had abandoned in the 1990s — or writing speeches, or attached to some other Murdoch initiative. In short order, several former Fox employees recalled, the organizational chart was taken down entirely.

A Fox spokeswoman said Mr. Brimelow did not currently have any relationship with the company. Mr. Brimelow declined to comment, writing in an email that The Times could not be trusted, so “you cannot expect any sane person to talk to you.”

In August 2018, Mr. Brimelow was spotted at a birthday party for the Trump adviser Larry Kudlow, drawing an article in The Washington Post and prompting the White House and Mr. Kudlow to distance themselves from Mr. Brimelow. But at Fox, some took the Brimelow discovery as an indirect explanation for the latitude Fox had extended Mr. Carlson on South Africa. If Mr. Murdoch had someone like Mr. Brimelow working for him, reasoned the former employee, he would have little objection to Mr. Carlson peddling far-right themes. (By coincidence, the same week Mr. Murdoch’s newspapers had begun their emergency-visa campaign in Australia, VDare published a story imploring Mr. Trump to welcome South African farmers to the United States.)

South Africa was not an aberration. In an echo of how Mr. Murdoch’s media empire had spent decades nurturing right-wing populism throughout the English-speaking world, Mr. Carlson had begun to fashion his show as a broader platform for nationalist ideas. From early on, he had promoted right-wing figures from abroad, people who could provide testimony on his themes of immigration and social decay. Now he was forging links with an increasingly globalized movement of populist activists and politicians — some of them eager for influence in Trump-era Washington.

Among those politicians was Hungary’s autocratic prime minister, Viktor Orban, a rising darling of the international far right. In late 2018, the Hungarian embassy hired a lobbyist, William Nixon, with business ties to Mr. Carlson’s father; within weeks, the lobbyist was in touch with Mr. Carlson about arranging an interview with the Hungarian foreign minister, who was planning a trip to Washington. During these talks, according to a person with knowledge of the conversations, Mr. Carlson mentioned that his head writer, Mr. Neff, was headed to Hungary the following year to report on how Mr. Orban was “improving the country.” (At the time, allies of Mr. Orban, a promoter of what he called “illiberal democracy,” had completed a sweeping takeover of the country’s news media, and the government would soon begin efforts to shut down a Budapest university founded by the liberal philanthropist George Soros.) In an email to The Times, Mr. Neff characterized his trip as a vacation.

Mr. Nixon connected Mr. Neff to the embassy to arrange interviews during the trip, according to the person with knowledge of the conversations. He also brought the Hungarian ambassador to Mr. Carlson’s Washington office, where the three men bonded over fly fishing, a popular pastime in Hungary. Mr. Carlson said he had long been interested in Mr. Orban and would welcome the chance to interview him.

That February, Mr. Carlson hosted the Hungarian foreign minister, Peter Szijjarto, who touted Mr. Orban’s hard line against immigration and his efforts to encourage families to have more children. And last summer, Mr. Carlson traveled to Budapest to produce what was in effect an extended infomercial for the Orban government. In a series of segments and a gentle interview with the prime minister himself, Mr. Carlson employed a sanitized version of Mr. Orban’s Hungary to frame his own arguments about an American civilization under attack by alien forces.

Where South Africa was a warning of the hell that America could become, Hungary was a vision of the paradise that could be had by taking America back. “You don’t have to watch your country collapse,” Mr. Carlson told viewers. “You don’t have to have leaders who hate the population or divide their own people against each other.”

Going Farther Afield

The day after the 2018 midterms, as darkness fell over Washington’s leafy Kent neighborhood, members of a local antifa group appeared outside Mr. Carlson’s home to protest his coverage of the migrant caravan. Standing in his driveway, yelling through bullhorns, they chanted, “We know where you sleep at night.” Mr. Carlson was not at home, but his wife, Susie Andrews, was. According to the Carlsons, someone banged on the door. Panicked, she locked herself in the pantry and dialed 911.

Mr. Carlson had lived in Washington for most of his adult life, and loved it. Two longtime friends said he was deeply shaken by the protests outside his home. “All of a sudden, it just became impossible to live there,” Mr. Carlson said in an interview last fall with Dave Rubin, a conservative YouTube personality and occasional guest on “Tucker Carlson Tonight.” He added, “I felt like we were really part of the city and then, next thing you know, people are showing up at the house.” He worried that “you’re going to wind up shooting somebody.” Within a year, he would flee Washington entirely, seeking asylum far beyond the Acela corridor.

In March 2019, Mr. Carlson set out to buy a dilapidated town garage in Bryant Pond, Maine, where his family had owned a vacation getaway for decades. In a letter to town officials, he pledged that Fox would install a state-of-the-art studio there. Mr. Carlson had never been guarded about his home in Bryant Pond, and often told interviewers about his love of Maine living. But when a local newspaper, The Sun Journal, published news of the proposed purchase, he lashed out like a man under siege. “All it does is hurt me,” he told the paper’s reporter, Steve Collins, explaining that Fox would never agree to leave $1 million worth of equipment in an isolated rural location if everyone knew about it. (Mr. Carlson would raise the stakes when The Times later assigned a freelancer to write about his life in Bryant Pond, accusing the paper of seeking to endanger his wife and children. A Maine-based freelance photographer, whom Mr. Carlson named on air, found his own door banged on by strangers after dark.)

In the end, Mr. Carlson proceeded with his plans, and by the following spring, The Sun Journal reported that his new studio was complete. He put his Washington house up for sale and began living in Maine much of the year, taping “Tucker Carlson Tonight” from Bryant Pond. (When not in Maine, Mr. Carlson usually broadcasts from Florida, where he has a second home in the resort town of Boca Grande.)

A different kind of threat was emerging inside Fox itself. In March 2019, the left-leaning watchdog group Media Matters surfaced old recordings of Mr. Carlson defending statutory rape and calling Iraqis “semiliterate primitive monkeys,” comments that had yet more advertisers fleeing and Fox colleagues fuming, especially some younger employees. That same month, the Fox opinion host Jeanine Pirro questioned on air whether Representative Ilhan Omar, a Minnesota Democrat and Somali-born former refugee, might be more loyal to her Muslim faith than to the Constitution. The slur prompted a young Muslim employee named Hufsa Kamal, who worked on Fox’s flagship news show, “Special Report With Bret Baier,” to chastise Ms. Pirro on Twitter — an extraordinary breach of the network’s hermetic culture. Not long after, as Ms. Kamal endured a stream of online abuse and threats from Fox fans, a producer in Fox’s Los Angeles bureau named Dan Gallo wrote to the company’s top human resources executives.

ROMANI REFUGEES

“When Fox personalities make these sorts of statements, it damages my credibility as a Fox journalist & my ability to effectively cover stories,” wrote Mr. Gallo, who provided copies of his emails to The Times. He argued that Mr. Carlson and Ms. Pirro were creating an unsafe workplace for employees like Ms. Kamal, and asked that Fox take action. “If an employee said those things in the workplace, especially with Muslim colleagues present, I think they would be disciplined,” Mr. Gallo wrote. (While Fox had issued a statement condemning Ms. Pirro’s remarks, she had not apologized.) Before sending his complaint, Mr. Gallo showed a copy to Ms. Kamal to make sure she was comfortable with it.

In a subsequent phone call, the executives, Kevin Lord and Nicolle Campa, seemed receptive, Mr. Gallo said in a statement to The Times. They thanked him for his letter and promised to relay it to Ms. Scott and Jay Wallace, Fox News’s president, so that they could understand the impact the hosts were having on the network’s journalists. Mr. Gallo assumed the complaint would otherwise remain confidential, as with other human resources matters.

A month later, Mr. Carlson landed in Los Angeles for a weeklong West Coast stint. Minutes after arriving in the bureau, he tracked down Mr. Gallo, who was sitting in an office talking to two colleagues. “Are you Dan Gallo?” he interrupted. When Mr. Gallo tried to introduce himself, an indignant Mr. Carlson simply handed him a blue notecard with his cellphone number. The next time Mr. Gallo had a problem with his show, Mr. Carlson said, he should “do the honorable thing” and call. Mr. Gallo offered to talk then and there, he said, but Mr. Carlson wasn’t interested. “I’m busy,” the host said, and walked off.

That night, Mr. Gallo wrote again to the human resources executives, asking who had told Mr. Carlson about his complaint. They promised to talk to Mr. Carlson. But pressed on the leak in a subsequent phone call, Mr. Lord refused to look into the matter. He blamed workplace gossip, and insinuated that Mr. Gallo himself was responsible for the leak. “That was insulting,” Mr. Gallo said. “I stuck to the proper channels and had moved on.” He left Fox that summer, and now works for MSNBC. (The writer of this article is an MSNBC contributor.)

Far from being chastened, Mr. Carlson seemed to be testing his boundaries. In August 2019, days after a 21-year-old white man killed 22 people at an El Paso Walmart to protest what he called the “Hispanic invasion of Texas,” Mr. Carlson declared on the air that white supremacy was largely a “hoax.” Even more advertisers fled; Mr. Carlson embarked on what Fox described as a preplanned vacation. While he was gone, a Fox producer named Cristina Corbin tweeted an indirect rejoinder to the prime-time star. “White supremacy is real, as evidenced by fact,” Ms. Corbin wrote. “Claims that it is a ‘hoax’ do not represent my views.”

She had not mentioned Fox’s star by name, but Mr. Carlson appeared to catch wind of her tweet almost immediately. A few hours later, while still on vacation, he called Ms. Corbin at work from a blocked number, then berated her for airing her disagreement publicly. “Shut your mouth,” he yelled, according to a former Fox executive briefed on the episode. Ms. Corbin did not respond to an email seeking comment for this article; Fox declined to comment, citing confidentiality requirements pertaining to human resources matters.

When Ms. Corbin reported the incident to Fox management, Mr. Carlson denied making such a call, according to the former executive. He was soon back to explaining to his viewers how liberals and Big Tech wanted them to “just shut up.”

The Backlash Pays

It was a frequent refrain on “Tucker Carlson Tonight”— and a calculated one. According to former Fox employees, Mr. Carlson and his team had learned to work the calls for boycotts and cancellation into their programming playbook. Mr. Carlson would grab third rails on race or immigration, then harvest the inevitable backlash, returning the next evening to roast his critics for trying to suppress an obvious truth. The feedback loop didn’t just drive up ratings. It boosted the audience’s loyalty to Fox, while encouraging audiences to identify with Mr. Carlson himself, now playing victim to the same forces he was warning them about. (Liberal-leaning outlets and Twitter influencers also capitalized on Mr. Carlson’s provocations, using clips from “Tucker Carlson Tonight” to attract and provoke his haters rather than his fans.)

In early June 2020, Mr. Carlson told his audience that the Black Lives Matter protests were “definitely not about Black lives” and to “remember that when they come for you.” The next evening, as Fox’s public relations team insisted Mr. Carlson’s comment was being mischaracterized, Mr. Carlson leaned in. “The mob came for us — irony of ironies,” he told Fox viewers. “They spent the last 24 hours trying to force the show off the air for good. They won’t succeed in that, thankfully. We work for one of the last brave companies in America, and they’re not intimidated.”

Off-camera, Mr. Carlson could be less defiant. In a conversation that spring with Eric Owens, one of his former employees at The Daily Caller, he worried that the controversy over his show had made it difficult for his children to get jobs and internships; he worried that his younger children wouldn’t get into college. “It’s not right for this to affect my family, and literally affect my children’s future,” Mr. Carlson said, according to Mr. Owens.

But it’s less clear whether the attacks significantly affected Fox’s bottom line: To compensate for the lost advertising, Fox turned “Tucker Carlson Tonight” into a promotional engine for the network itself. It replaced the fleeing sponsors with a torrent of in-house promos, leveraging Mr. Carlson’s popularity to drive viewers to other, more advertiser-friendly offerings. By early 2019, roughly a fifth of all advertising “impressions” on the show were from in-house ads, according to data from the analytics company iSpot.tv. That summer, as Fox fended off criticism of Mr. Carlson’s “hoax” comments, the proportion climbed to more than a third. (A Fox spokeswoman said the actual proportions were lower, but declined to provide specific figures.) “Fox is basically an enormous loyalty brand,” said Jason Damata, the chief executive officer of Fabric Media, a media consultancy. “He’s the hook.”

Other advertising slots were taken by direct-to-consumer brands that either didn’t care about Mr. Carlson’s bad publicity or saw that they could use his intensity to sell their products. Beginning in January 2019, MyPillow, a Fox advertiser whose chief executive, Mike Lindell, is a major promoter of Mr. Trump’s stolen-election lie, began airing more than $1 million worth of ads on “Tucker Carlson Tonight” each month. Fox appeared to be using MyPillow to cushion Mr. Carlson: As other advertising dried up, the company’s ads spiked. (All told, through December 2021, Mr. Lindell had bought advertising that would have cost $91 million at publicized rates; discounts probably made that sum lower.)

Blue-chip advertisers would never return to the show in force. But thanks in part to the large audiences he could provide for those advertisers who remained, and the premium prices Fox could charge them, Mr. Carlson’s ad revenue began to recover. Every year since 2018, “Tucker Carlson Tonight” has brought more annual ad revenue to Fox than any other show, according to estimates by iSpot. Last May, after promoting the white supremacist “replacement” theory, Mr. Carlson had half as many advertisers as in December 2018 but brought in almost twice as much money.

As “Tucker Carlson Tonight” became more toxic to advertisers, it also began featuring fewer guests who disagreed with the host, and more guests who simply echoed or amplified Mr. Carlson’s own message. It wasn’t just that liberals didn’t want to debate him, though some now refused to appear on the show, as Mr. Carlson complained during a Fox appearance last summer; Fox was learning that its audience didn’t necessarily like hearing from the other side. “From my discussions with Fox News bookers, my takeaway is that they’ve made the judgment that they just don’t do debate segments anymore,” said Richard Goodstein, a Democratic lobbyist and campaign adviser who appeared regularly on Mr. Carlson’s show until the summer of 2020. Across much of the Fox lineup, former employees said, producers were relying more and more on panels of pro-Trump conservatives competing to see who could denounce Democrats more fervently — a ratings gambit one former Fox employee called “rage inflation.” (One exception, perhaps, is “The Five,” a panel show featuring four conservative co-hosts and one rotating co-host from the left, which has beaten Mr. Carlson in total viewers in some recent months.)

And as advertisers fled, Mr. Carlson’s opening monologue grew. Where once he spoke for only a few minutes, sometimes in a neutral just-asking-questions mode, he now often opened the show with a lengthy stemwinder, addressing his audience as “you” and the objects of his fury as a shadowy “they.” Ratings data showed that the monologues were a hit with viewers, according to one former and one current Fox employee, and by 2020, Mr. Carlson regularly spoke directly to the camera for more than quarter of the hourlong show. Instead of less Tucker, the audience got more.

His critics at Fox found themselves further marginalized: After an on-air feud with Mr. Carlson over the legality of Mr. Trump’s efforts to pressure Ukrainian officials, Shepard Smith was reportedly warned against criticizing his fellow host, and he departed Fox in October 2019. Mr. Carlson’s ratings grew, buoyed by the increasingly heated and apocalyptic presidential campaign. One night in June 2020, after yet another commercial-to-commercial attack on Black Lives Matter protesters, Mr. Carlson addressed the matter directly. Ratings were more than just ammunition in the cable-news wars, Mr. Carlson explained. They were proof that his viewers were not alone, proof that they were . “Last night, we did something we don’t do very often: We spent the entire first block of the show on a single topic,” he said. More people had watched the previous night’s show, he observed, than any other hour of prime-time television that evening — more than the old evening news broadcasts, more than any sitcoms or sports events. “Millions and millions of Americans agree with you,” he said. “You are not crazy. Your views are not evil.”

That month, another Fox employee complained to human resources that Mr. Carlson’s on-air statements contradicted Mr. Murdoch’s public pledge to “support our Black colleagues” in the wake of George Floyd’s killing. In response, an executive cited the company’s need to allow “diverse voices and perspectives,” according to a person familiar with the exchange. At the end of the month, when the Nielsen figures trickled in, Fox sent out a triumphant news release: Mr. Carlson had posted the highest quarterly ratings of any cable news show in history — breaking Mr. Hannity’s old record and helping make Fox the most-watched channel on all of basic cable.

An Upside-Down Nation

In the end, it was Fox’s own political unit, a bastion of traditional news-gathering, that brought the network’s increasingly wobbly balancing act to an end. Just before midnight on Election Day, hours ahead of other networks and news consortiums, Fox announced that Joseph R. Biden Jr. had won the swing state of Arizona. Mr. Trump instantly declared the result a “fraud,” but the following Saturday, as late votes trickled in, Mr. Biden won Pennsylvania, ending the presidential race.

Mr. Trump’s defeat was the ultimate glitch in Fox’s Trump narrative, one that couldn’t be so easily spun or papered over by its prime-time hosts. Despondent Trump supporters began to look elsewhere for news, encouraged by anti-Fox tweets from Mr. Trump himself. In early December, the upstart conservative network Newsmax, which had positioned itself as even more devotedly pro-Trump, scored its first ratings win over Fox. It was a minor crack in Fox’s cable dominance — fewer than 30,000 viewers in one audience segment on a single December night in the 7 p.m. hour — but it sent shudders through the Fox executive suites. The network might shrug off the complaints of a few advertisers; losing audience to a right-leaning rival was another thing. That month, according to one former Fox executive, Rupert Murdoch delivered a message to the network’s president, Ms. Scott: Clean house. (A Fox spokeswoman disputed this description.)

The purge would not come until early January, as CNN and MSNBC overtook Fox, the cable-news ratings leader for two decades, and as Washington reeled from the violent, Trump-inspired effort to overturn Mr. Biden’s victory. In the intervening weeks, Mr. Carlson and other Fox prime-time hosts would pump out a steady stream of attacks on the election results, often drawing on claims of voter fraud from Mr. Trump and his new legal team, led by Rudolph W. Giuliani. Fox’s prime-time guns also aimed inward: When a Fox White House correspondent and occasional Carlson guest, Kristin Fisher, told viewers that much of one rambling Giuliani presentation “was simply not true or has already been thrown out in court,” Mr. Carlson went on the air to attack “credentialed reporters, some of whom we know and like,” who were refusing “even to acknowledge” the already discredited claims. He had not mentioned Ms. Fisher by name, but she was warned by superiors to keep her head down, according to two former employees. She did not reappear on air for several days, and her appearances declined significantly in subsequent weeks. (Ms. Fisher later left for CNN.) Around the network, supervisors repeated an Orwellian mantra: “Respect the audience.”

CAPITOL RIOT

Much as Mr. Carlson’s vast cable audience had grown to encompass the white nationalist fringe, it now drew in some of the hundreds who would go on to attack the Capitol. At least eight people now facing criminal charges stemming from the insurrection commented on Mr. Carlson’s official Facebook page in the preceding months, according to an analysis of since-deleted Facebook accounts conducted for The Times by CounterAction, a security firm. They included Graydon Young and Connie Meggs, members of the Oath Keepers militia organization who would be indicted on federal conspiracy charges. Another Carlson fan was Tammy Bronsburg, who on Election Day posted “WE ARE TAKING OUR COUNTRY BACK.” Two months later, she donned a Trump flag as a cape and joined the crowd breaking into the Capitol. (Mr. Young pleaded guilty and is cooperating with the government against the Oath Keepers; Ms. Meggs and Ms. Bronsburg are fighting the charges against them. Their lawyers did not comment on the Facebook posts.) Later that day, as the Capitol lay stained with blood and broken glass, the Proud Boys posted a defiant message of justification on the Parler social media platform, borrowing a meme from Mr. Carlson’s segments on Black Lives Matter. The lesson of the civil rights protests, Mr. Carlson had claimed, was that “violence works.”

Soon after the Capitol riot, Fox replaced its 7 p.m. host — Martha MacCallum, a news anchor and part of the political reporting team — with another hour of right-wing opinion programming. Mr. Stirewalt, the political editor, who had vanished from the air after defending the Arizona call, was fired; his boss, Fox’s Washington bureau chief, Bill Sammon, retired. More than a dozen reporters for Fox’s digital arm were also laid off, a culling that followed pre-election layoffs in the Brain Room, the in-house research and fact-checking division. Publicly, Fox portrayed these changes as a restructuring, but as with the Moneyball initiative, their impact was felt chiefly in the news ranks, now an expensive and increasingly distracting legacy of the Ailes era.

Trumpism without Trump had begun as a programming strategy. Now, with Mr. Trump gone from the White House and cut off from Twitter and Facebook, it has become a reality. Mr. Carlson, more successfully than any other figure on the right, has filled the vacuum, picking up the banner of Mr. Trump’s movement and the followers who insist he was cheated of victory. Last year, according to The Times’s analysis, nearly half of Mr. Carlson’s shows — more than 100 episodes — included segments playing down the Capitol riot, lurching into ever more fantastical terrain. Much as he once recast the country’s racial hierarchy to make white Americans an oppressed class, Mr. Carlson has inverted the story of Jan. 6 into a modern-day Lost Cause. On “Tucker Carlson Tonight,” the rioters were not aggressors; they were victims. Last June, he floated a conspiracy theory that the riot was an inside job, claiming that an “unindicted co-conspirator” in a government court filing was “almost certainly working for the F.B.I.” In fact, it was Sharon Caldwell, the wife of an insurrectionist with ties to the Oath Keepers; a few months later, Mr. Carlson brought Ms. Caldwell onto the show, now casting her and her husband as the victims of overzealous prosecutors.

This past fall, Mr. Carlson and his team distilled the show’s Jan. 6 fantasia into “Patriot Purge,” a three-part “documentary” for the Fox Nation streaming channel. After a trailer aired in late October, two longtime Fox contributors quit in protest. Mainstream media outlets and fact-checking sites inevitably eviscerated Mr. Carlson’s work for its factual errors and dubious assertions, but that was beside the point. After starting the year with the lowest ratings in cable news, Fox ended 2021 back on top. And Mr. Carlson’s inverted, invented narrative of the Jan. 6 insurrection has become a new Republican orthodoxy: This February, members of the Republican National Committee approved a resolution calling investigations into the attack a “persecution of ordinary citizens engaged in legitimate political discourse,” censuring two Republicans who sit on a congressional panel scrutinizing the riot. “Propaganda tends to bewilder people, to confuse them when they first hear it,” Mr. Carlson observed last fall, in a monologue accusing liberals and mainstream outlets of themselves misleading the public about Covid-19, Jan. 6, and the 2020 elections. “It is so completely and obviously untrue,” he continued. “‘What is this?’ you think. And yet for that very reason, because it’s so ridiculous, so absurd, propaganda tends to be effective.”

Reporting was contributed by Larry Buchanan, Weiyi Cai, Ben Decker, Alan Feuer, Barbara Harvey, Kenneth P. Vogel and Karen Yourish. Jack Begg and Julie Tate contributed research.