In 1962, some of America’s most influential conservatives met to talk about a growing threat: the rise of paranoid conspiracy theories on the right.

Sen. Barry Goldwater (R-Ariz.) was thinking about running for president. A mutual friend set up a meeting for Goldwater with William F. Buckley Jr., editor of the conservative National Review, and Russell Kirk, author of the 1953 book “The Conservative Mind.”

In a hotel suite in Palm Beach, Fla., Buckley and Kirk found themselves giving Goldwater advice about how to respond to the ultra-right-wing John Birch Society’s surge in popularity. The society, founded in 1958, was fiercely anti-communist — and fond of crackpot theories. Its founder, candy manufacturer Robert Welch, had accused most of the U.S. government — including former Republican president Dwight D. Eisenhower — of being under secret communist control.

Although Welch had been an early donor to Buckley’s National Review in the 1950s, Buckley had come to believe that Welch’s feverish rants threatened the conservative movement’s credibility and its future.

“Buckley was beginning to worry that with the John Birch Society growing so rapidly, the right-wing upsurge in the country would take an ugly, even Fascist turn,” John B. Judis wrote in his 1988 biography, “William F. Buckley, Jr.: Patron Saint of the Conservatives.” Buckley told Goldwater, according to Judis, that the John Birch Society was a “menace” to the conservative movement.

“Kirk, unimpeded by his little professorial stutter, greeted the subject with fervor,” Buckley recalled in a 2008 article for Commentary. “The John Birch Society should be renounced by Goldwater and by everyone else — Kirk turned his eyes on me — with any influence on the conservative movement.”

QAnon, a baseless conspiracy theory, is fueled by right-wing outrage online and in the real world. (Elyse Samuels/The Washington Post)

But Goldwater had a problem — much like the one that Republican leaders face today, as many of their voters embrace QAnon conspiracy theories and President Trump’s false claims of a stolen election. Goldwater wanted to distance himself from the conspiracy theories, but he feared alienating his base.

“Every other person in Phoenix is a member of the John Birch Society,” Goldwater told Buckley and Kirk. “I’m not talking about commie-haunted apple pickers or cactus drunks. I’m talking about the highest cast of men of affairs.”

After considering Goldwater’s concerns, Buckley and Kirk agreed to a compromise. They would challenge Welch without directly criticizing the John Birch Society’s members, creating an opening for Goldwater to do likewise. Gingerly at first, but more forcefully as the 1960s went on, the conservative thought leaders began to distance themselves from the Birchers’ paranoid denunciations of the U.S. government.

Within weeks, Buckley wrote a 5,000-word National Review editorial criticizing Welch. “How can the John Birch Society be an effective political instrument while it is led by a man whose views on current affairs are … so far removed from common sense?” Buckley asked. “The underlying problem is whether conservatives can continue to acquiesce quietly in a rendition of the causes of the decline of the Republic and the entire Western world which is false.”

Goldwater responded with a letter to the National Review that called on Welch to resign from the society. “Mr. Welch is only one man, and I do not believe his views, far removed from reality and common sense as they are, represent the feelings of most members of the John Birch Society,” Goldwater wrote in the letter, published in the magazine’s next issue. “We cannot allow the emblem of irresponsibility to attach to the conservative banner.”

Welch had founded the John Birch Society four years earlier with a two-day presentation to several fellow business executives about alleged communist influence in government. Welch named the group after U.S. Army Capt. John M. Birch, an intelligence officer killed by Chinese communist soldiers in August 1945. Welch considered Birch the Cold War’s first casualty.

Conspiracy theories pervaded Welch’s writing. His screed “The Politician” called President Eisenhower a “dedicated, conscious agent of the Communist conspiracy.” The U.S. government, Welch alleged in 1961, was “50 to 70 percent” communist-controlled. Black southerners’ agitation for civil rights, Welch claimed, “has been fomented also entirely by the Communists.”

The John Birch Society claimed 100,000 members at its peak, and its magazine and pamphlets influenced more people than that. Its billboards across the country called for impeaching Chief Justice Earl Warren over the Supreme Court’s decisions in favor of civil liberties and desegregation. Congressional offices were deluged with batches of similar letters advocating the society’s causes, such as abolishing the income tax, boycotting goods from communist countries, and preserving the House Un-American Activities Committee. The group even blamed communists for American cities putting fluoride in their water for dental health.

By 1962, the John Birch Society had become a major faction on the American right, especially in California. Richard M. Nixon, running for governor there, denounced the group, called on all Republicans to do the same, and said he wouldn’t endorse any Birchers for political office. Nixon’s reward was an outpouring of right-wing support for his opponent in the Republican primary and anemic support from the right in the general election, which Nixon lost.

When Goldwater ran for president in 1964, he didn’t want to lose support from Birchers, his fellow anti-communists. So he stuck to the distinction he’d insisted on to Buckley and Kirk: Welch was unhinged from reality, but average Birch Society members were okay.

“They believe in the Constitution, they believe in God, they believe in freedom,” Goldwater said that March. “I don’t consider the John Birch Society as a group to be extremist,” he added that April.

At the 1964 Republican convention, which nominated Goldwater for president, his supporters voted down a proposed platform plank that would have denounced the John Birch Society and other extremist groups. “Extremism in the defense of liberty is no vice,” Goldwater declared in his acceptance speech — thrilling archconservatives and helping to doom him to a landslide defeat by President Lyndon B. Johnson.

By 1965, disdain for the John Birch Society was common outside conservative circles. Historian Richard Hofstadter had named Welch and his group as prime examples in his seminal article, “The Paranoid Style in American Politics.” Bob Dylan had mocked the society with his song “Talkin’ John Birch Paranoid Blues.” But hardline conservatives who feared Johnson’s liberal Great Society programs continued to flock to Welch’s organization. California alone was home to an estimated 10,000 members and 1,000 chapters.

When Buckley saw the August 1965 issue of the Birch Society’s magazine, American Opinion, he was appalled at its latest fevered conspiracy claims — and its argument for U.S. withdrawal from Vietnam so that the nation could focus on fighting communism at home. Buckley denounced the magazine in his nationally syndicated newspaper column, including its description of civil rights protesters in Selma, Ala., as “a horde of termites from all over the country,” and its claims that the State Department, Justice Department and Supreme Court were either communist-dominated or taking orders from a foreign dictatorship.

“One continues to wonder,” Buckley wrote, “how it is that the membership of the John Birch Society tolerates such paranoid and unpatriotic drivel.” Hate mail and subscription cancellations from outraged Birchers flooded the National Review’s office. So Buckley doubled down in follow-up columns, suggesting that Welch represented the membership’s true feelings after all.

Meanwhile, Ronald Reagan, the actor turned Goldwater supporter, was considering a run for governor of California in 1966. Although he didn’t like Welch’s smear of Eisenhower, “Reagan seemed reluctant to distance himself from the Birch Society,” Matthew Dallek wrote in “The Right Moment: Ronald Reagan’s First Victory and the Decisive Turning Point in American Politics.” Reagan’s complaints about a “Communist plot” in the film industry “dovetailed nicely with the society’s [beliefs],” Dallek wrote, “and for the most part Reagan applauded the men and women who peopled its ranks. They were, he implied on more than one occasion, patriotic Americans who deserved recognition for their steadfast devotion to the Republic.”

But in September 1965, as buzz about him and the John Birch Society grew, Reagan realized that he’d have to distance himself from the group. “I am not a member,” Reagan declared at a Republican fundraiser. “I have no intention of becoming a member. I am not going to solicit their support.” Reagan added that a “lunatic fringe” had infiltrated the society and that he was in “great disagreement” with Welch. (Reagan went on to win the California governorship, despite Democratic incumbent Pat Brown’s attempts to tie him to the Birchers.)

A week after Reagan’s statement, Republican congressional leaders Everett Dirksen and Gerald Ford, the future president, jointly denounced the John Birch Society. Buckley kept up his attack, publishing a 14-page special section critical of the Birchers in the National Review in October 1965. Buckley’s editorial declared that the Birch Society had reached “a new level of virulence, a new level of panic.” He warned that the taint of Bircherism could sink Reagan and other conservative candidates in 1966. Goldwater joined in, going farther than he’d had before. In a new letter to the magazine, the former presidential candidate declared that if Welch didn’t resign from the Birch Society, conservatives should resign from it and work instead to support the GOP.

Although the Birch Society still exists today, the renunciations that Buckley led in fall 1965 marked the beginning of the end of its influence over conservative politics. “No fig leaf of respectability remained,” wrote Carl T. Bogus in his 2013 biography, “Buckley: William F. Buckley and the Rise of American Conservatism.” “The society went into steep decline. Recruiting new members was exceedingly difficult. … Even highly visible members quit.” The conservative movement had excommunicated the Birchers’ conspiratorial, unpatriotic hostility — for the next few decades, at least.

Erick Trickey is a Boston-based freelance writer who teaches magazine journalism at Boston University.

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