Rush Limbaugh, who deployed comic bombast and relentless bashing of liberals, feminists and environmentalists to become the nation’s most popular radio talk-show host and lead the Republican Party into a politics of anger and obstruction, died Feb. 17 at 70.

The cause was complications from lung cancer, his wife, Kathryn Limbaugh, said at the start of his Wednesday radio show.

In February 2020, Mr. Limbaugh, a cigar aficionado who long defended tobacco use, told his audience that he had been diagnosed with advanced lung cancer. One night later, President Donald Trump broke with tradition and bestowed on him the Presidential Medal of Freedom, the nation’s highest civilian honor, during the State of the Union address.

“He is the greatest fighter that you will ever meet,” Trump said.

For more than two decades, starting in the late 1980s, Mr. Limbaugh dominated the airwaves, inspiring a generation of conservative talk show hosts and politicians. He parlayed his popularity on the radio into stints as a TV commentator, football analyst on ESPN and best-selling author of incendiary political books.

He saw himself as a teacher, polemicist, media critic and GOP strategist, but above all as an entertainer and salesman. Mr. Limbaugh mocked Democrats and liberals, touted a traditional Midwestern, moralistic patriotism and presented himself on the air as a biting but jovial know-it-all who pontificated “with half my brain tied behind my back just to make it fair,” as he often said.

Especially during the Democratic presidencies of Bill Clinton and Barack Obama, Mr. Limbaugh played a leading role in demonizing liberals and pushing conservative elected officials to hard lines on issues such as immigration, government spending and denial of climate change.

During Republican presidencies, Mr. Limbaugh became a leading defender of the faith, even when that meant veering away from long-standing principles. A lifelong deficit hawk who supported Sen. Ted Cruz, R-Texas, in the 2016 Republican presidential primaries, Mr. Limbaugh often criticized businessman Donald Trump, saying, “Trump is not a conservative.”

But in the general election, Mr. Limbaugh embraced Trump. The radio host and the new president became dinner and golf friends, and Mr. Limbaugh emerged as a staunch supporter of Trump’s battles against the news media and the Republican establishment. He railed against Trump’s impeachments in 2019 and 2021 and allied himself with Trump during the coronavirus pandemic, insisting that the disease was no worse than the common cold.

After Trump lost the 2020 election, Mr. Limbaugh echoed the president’s baseless allegations of voting fraud and suggested that pro-Trump states consider seceding from the union.

Trump, Mr. Limbaugh said on his show this month, “represents an uprising of the people of this country against Washington, against the establishment, and it had been building for a long time … since Perot in 1992 … Trump was just the first guy to come along and actually weaponize it.”

Like Trump, Mr. Limbaugh mastered the art of portraying himself as a man of the people who fought the elites even as he relished a luxe life in which he collected $5,000 bottles of wine, owned a $54 million private jet, outfitted the vast salon of his Florida manse in the manner of Versailles, and socialized with top corporate and political leaders. Mr. Limbaugh often praised Trump for succeeding despite never having won over the kind of people who ran large media organizations, Wall Street firms and political parties.

And like Trump, Mr. Limbaugh craved the respect of those he criticized most vociferously. His commentaries about Trump became notably more favorable as he became a frequent golf partner with the president, just as his on-air attitude toward President George W. Bush became more supportive after the chief executive invited the radio host to dinner, a show and an overnight in the Lincoln Bedroom.

For decades, Mr. Limbaugh had been a powerful voice in Republican politics. In 1994, he reached beyond his radio show and lectures in large arenas to join Republican candidates at fundraisers — helping the party regain the majority in the U.S. House of Representatives with its signature Contract With America, a populist agenda that would define GOP aims for many years to come. Mr. Limbaugh dubbed himself “the most dangerous man in America.”

“His effect as an enforcer, keeping Republican politicians in line, was greater than that of a president or the party’s national organization,” said Zev Chafets, author of the biography “Rush Limbaugh: An Army of One” (2010), in a 2017 interview with The Washington Post.

Or, as Mr. Limbaugh once put it, “Things only take off when I mention them.”

At the peak of his popularity, restaurants across the nation rechristened their empty overflow space “Rush Rooms” and piped in the show, filling seats at lunchtime with fans who called one another “Dittoheads” because they agreed with every pearl of Limbaughian wisdom.

“He was the Elvis of broadcast radio,” Chafets said. “He knew politics very well and he was extremely successful as a businessman, but the thing he’ll be remembered for is he was a genius at broadcasting, at performing on the radio.”

Although critics of the show spent decades decrying it as offensive, even cruel, his fans defended Mr. Limbaugh’s insults as more funny than slashing. He won attention from far beyond his radio audience with barbs aimed at gays; Blacks; liberals; feminists, whom he sometimes called “feminazis”; and environmentalists, whom he derided as “tree-huggers.”

He was the first national radio host to focus almost exclusively on politics while entertaining his mostly White and male audience with song parodies, wacky imitations (his Bill Clinton was uncanny), and phony commercials, such as one for “Feminazi Trading Cards” — all antics he had practiced for years as a Top 40 radio DJ.

He won gleeful “dittos” from listeners who believed that American culture had become too politically correct. He spawned a mini-industry of anti-Limbaugh books and radio hosts who pronounced themselves appalled by his comedy bits, such as an “AIDS Update” that presented nasty nuggets about gays to the strains of Dionne Warwick’s “I’ll Never Love This Way Again.” For a time, he dispatched hostile callers on his show with “caller abortions,” in which he played the sound of a vacuum pump before hanging up on the listener.

Although his Democratic critics derided Limbaugh listeners as uneducated and easily led, a study by the Pew Research Center found that Dittoheads were on average better informed than listeners of NPR and were more likely than public radio or C-SPAN audiences to have a college degree.

His first book, “The Way Things Ought to Be” (1992), sat atop The New York Times bestseller list for six months; it spelled out his political philosophy, a blend of nostalgic yearnings for a more united and homogeneous America and energetic embrace of individual rights. “I believe in the individual, in less government,” he wrote, “that God placed man in a position of having dominion over nature … [and] that racial relations will not be enhanced or prejudice eliminated by governmental edict.”

He worked for a time as a football commentator on ESPN but lost that gig in 2003 after saying on “Sunday NFL Countdown” that Donovan McNabb, a Black quarterback for the Eagles, got more credit than he deserved because “the media has been very desirous that a Black quarterback can do well.”

Mr. Limbaugh’s fame and influence survived his hearing loss in 2001 (he suffered from an autoimmune disease but was able to restore some hearing through cochlear implants), his admission in 2003 that he was addicted to prescription painkillers, and an arrest in 2006 for doctor-shopping in his quest for more oxycodone pills. The charges were dropped when he agreed to go into rehab. His addiction resulted from “immaturity and my childhood desire for acceptance,” he said after taking six weeks off for treatment.

His career began to wane as the populist nationalism that Trump espoused shouldered out more-traditional Reagan conservatism and as podcasts and satellite radio eroded broadcast radio’s hold on Americans’ attention.

By the time Trump took office as president in 2017, the talk host who called himself “America’s Anchorman” had been nudged off center stage. In the end, he was overshadowed by Fox News Channel and more-extreme right-wing outlets such as Breitbart News and Infowars, which owed their existence to Mr. Limbaugh’s pioneering of conservative talk as an alternative to the “drive-by media” — his derisive term for what he saw as a scandal-hungry, liberal-dominated national press corps.

Mr. Limbaugh’s influence could be heard in Trump’s denunciations of “fake news.” Decades before Trump entered politics, Mr. Limbaugh gave the news media prominent billing in his catalog of villains, casting doubt on verified accounts.

Even as his audience declined, Mr. Limbaugh made about $40 million a year for spending three hours a day broadcasting from a studio near his Palm Beach estate, reaching more than 13 million weekly listeners on about 600 stations — down from a peak audience of more than 20 million listeners in the 1990s. A month before announcing his cancer diagnosis, Mr. Limbaugh had signed a four-year extension of his radio show.

He lost some advertisers after an incident in 2012 in which he called a Georgetown University law school student, Sandra Fluke, a “slut” because she had testified in Congress on behalf of mandating coverage for contraception in health insurance policies. A boycott launched by his liberal critics to protest Mr. Limbaugh’s comments about women and minorities resulted in the loss of several prominent sponsors.

The beginnings

Rush Hudson Limbaugh III was born in Cape Girardeau, Mo., on Jan. 12, 1951, to a family of lawyers. An uncle and cousin were federal judges. The federal courthouse in his hometown was named for his grandfather and namesake.

His mother, the former Mildred “Millie” Armstrong, who was a Republican committeewoman for many years, was the source of his humor, and his father, who served as the county Republican chairman, was his rhetorical mentor, given to delivering extended political lectures over dinner.

The father wanted his son to follow him into the law, but Mr. Limbaugh pined for an audience larger than any courtroom could offer. He “didn’t start talking until he was 2,” his mother once said, “and then he didn’t stop.”

A chubby boy who lacked close friends, Rush was 12 when he got his most prized gift, a Remco Caravelle, a blue plastic transistor radio on which he would listen to his hero, Chicago’s premier Top-40 jock, Larry Lujack. On WLS, Lujack filled the spaces between pop songs with desk-thumping, flashy jingles and a blizzard of sound effects. His shtick was a winking grandiosity: He regularly told his listeners that he was “serving humanity.”

All of those elements became part of Mr. Limbaugh’s homespun radio show, broadcast from his bedroom to the rest of his house. He would play records and put a microphone up to the turntable speaker.

“Almost everybody who is in any way a performer has always known they wanted to do it,” he told The Washington Post, “to be the focus of attention, to be more than yourself outside yourself.”

Mr. Limbaugh started working at a local radio station, of which his father was a part-owner, while he was still in high school. In 1972, he dropped out of Southeast Missouri State University after one year to take a job as a Top-40 DJ in McKeesport, Pa. “He flunked everything,” his mother told Limbaugh biographer Paul Colford. “He just didn’t seem interested in anything but radio.” He avoided the military draft by winning a medical deferment based, he said, on a “football knee” and a cyst on his rear end.

At WIXZ, an AM station, Mr. Limbaugh was assigned a new name, as often happened in radio. With his booming voice, bad-boy comedy and boastful persona, “Jeff Christie” was a master of Top-40 technique. His show was always coming at you from the “Excellence in Broadcasting” studios. Song titles were announced with pseudo-British pronunciations. Although Christie’s show was all about the hits and not the politics, he aimed his comedic bits at targets such as feminists and hippies.

One morning in 1973, he came out of the song, “Love Can Make You Happy,” with the quip, “Women’s liberation theme song there for you.”

His bosses were not amused. The more he sneaked bits of topical satire between the hits, the more his managers directed him to stick to the lines they wrote for him on index cards.

Turning to baseball

Mr. Limbaugh became a journeyman DJ, flitting from station to station, sometimes as Rusty Sharpe, sometimes as Christie. In 1979, having concluded that he was never going to get to the big time, he quit radio.

“I was tired of being considered a dope-smoking pothead who knew nothing other than Donny Osmond records,” Mr. Limbaugh said. He returned home to take a job with the Kansas City Royals as director of group sales. After five years in baseball, he found a position as a news and opinion announcer at a Kansas City station. But he was fired for getting too partisan in his commentaries.

In 1984, a station in Sacramento, Calif., gave him a talk show. Far from leaving his DJ years behind, Mr. Limbaugh modeled his new program after the basic format of Top-40 radio, replacing the songs with listener phone calls but otherwise retaining the elements of what had long been radio’s most alluring programming: jingles, rock “bumpers” (the snippets of songs that led listeners in and out of each segment), teases about what was coming up after the ads, and constant self-promotion.

Mr. Limbaugh’s daily dicing of California politicians, spiced with comedy routines and news updates packaged with pop tunes, was an instant hit.

As Mr. Limbaugh became a local star, radio was undergoing a revolution. Satellite technology made it possible for many stations to air the same programs cheaply, and federal regulators stopped enforcing rules requiring balance in political programming. The changes opened the door for Mr. Limbaugh to go national and, in 1988, ABC Radio offered him a deal that included a local morning show on WABC in New York and a nationally syndicated afternoon show.

He had an immediate knack for making headlines with his put-downs, as when he criticized “environmental wackos” and declared animal rights activists to be “a bunch of kookburgers.”

After 20 months of syndication, “The Rush Limbaugh Show” became the nation’s most popular radio talk program.

“I represent a group of people who aren’t heard from very much in the media, the average normal American guy and his family,” he said, introducing himself as a guest-host on CBS-TV’s “Pat Sajak Show” in 1990. “I have the unique ability to take the opposing point of view and just nuke it, laser it out of existence … I am addicted to self-praise.

“People say, ‘You really believe the stuff you say?’ That’s for you to figure out.”

During that CBS show, Mr. Limbaugh waded into the crowd to interview audience members, but activists from ACT UP, a gay rights group, had packed the room and shouted him down.

The more liberals protested his excesses, the more he doubled down. He derided the notion of women in combat as “the All-American First Cavalry Amazon Battalion.” On Phil Donahue’s TV talk show in 1992, Mr. Limbaugh said he could not understand how women could say they were ready for combat duty, but “let some guy in an office come along and go” — he patted his own behind to demonstrate “fanny-patting” — “and they gotta run off to some legal authority, ‘You harassed me! You harassed me!’ If you’re a man interested in a woman, you are guilty of sexual harassment in America today.”

“I like to illustrate absurdity by being absurd,” he said.

Republican politicians hungered to be associated with Mr. Limbaugh. In 1992, President George H.W. Bush, then seeking a second term, invited him to the White House for an overnight visit. That year, when Bill Clinton defeated Bush, Republicans were divided and forlorn, and “all we had to hold us together was Rush Limbaugh,” said one of Bush’s top strategists, Mary Matalin.

From 1992 to 1996, Mr. Limbaugh also hosted a late-night TV show, produced by Roger Ailes, the longtime media adviser to Republican presidents, who would go on to found Fox News Channel. But TV was not his medium; his talent was grounded in using radio as a theater of the mind, a forum in which he could become an emotionally needy Bill Clinton or mock Obama by talking over the president’s speeches.

A power hitter

Democrats and Republicans alike credited Mr. Limbaugh with political influence well beyond that of any radio host since Walter Winchell half a century earlier.

In 1994, freshmen Republicans in Congress made him an honorary member of their class. Sarah Palin, the former governor of Alaska who was the Republican candidate for vice president in 2008, used a Limbaughism as her big applause line in speeches: “Republicans are not just the party of ‘no,’ but the party of ‘hell, no!’ "

Late in his career, Mr. Limbaugh wrote a series of adventure books for children about episodes in American history. He had no children; his marriages to Roxy McNeely, Michelle Sixta and Marta Fitzgerald ended in divorce. In 2010, he married Kathryn Rogers, an event planner 26 years his junior, at a ceremony where Elton John was hired to perform. Complete information on survivors was not immediately available.

Mr. Limbaugh at times boasted that he gave millions of Americans instructions on what to believe about politics. But at other moments, he presented himself as a mere mirror of public opinion. “I don’t orchestrate, dictate or otherwise cause people to ponder,” he wrote in one of his bestsellers. “I simply validate.”

A caller once confronted him on a TV show, saying, “You’re a manipulator, you’re devious and you’re evil.”

“I’m a harmless little fuzzball,” Mr. Limbaugh replied. “Nobody makes you listen to me … The show is about having fun.”