Adapted from Fantasyland: How America Went Haywire: A 500-Year History © 2017 by Kurt Andersen. With permission from Random House. All rights reserved.

The frenzy on the right to discredit Robert Mueller’s investigation gets more astonishingly desperate by the day—spurred not just by breathless talk radio and Fox News hosts, but also by Republican members of the House, who this week voted to release a Republican memo suggesting the Russia investigation is a partisan plot against President Trump. As Eric Levitz summarizes in New York magazine, Trump supporters’ evolving conspiracy theory posits that “the entire investigation into alleged collusion between the Trump campaign and the Russian government is a baseless sham orchestrated by Hillary Clinton and her deep-state allies,” including “a ‘secret society’ of Democratic operatives embedded within the FBI.”

So the right has lost its collective mind. But it has been heading this way for a long time. Back in 1954, after the Senate (including half of his fellow Republicans) censured Joe McCarthy, the pathogens of his conspiracy madness remained, and a generation ago began seriously propagating and infecting the mainstream, weakening its immunities to a demagogue like Donald Trump. Looking back at that Republican history, it’s clear that the party’s reality-based Establishment was in charge from the 1960s through the ’80s, exploiting but marginalizing its useful idiots. It wasn’t until the age of right-wing talk radio and Fox News and Breitbart that the Establishment lost control, as crackpot habits of mind achieved dominance. Indeed, more and more of the reckless, hysterical conspiracist language of Trump’s frenzied defenders in the mainstream resembles that of the lunatic, fringe right from a half-century ago.

After the new John Birch Society picked up the McCarthyist baton in the early 1960s, it started getting huge national media attention. The organization recruited tens of thousands of members in chapters in dozens of states. The federal government, the deep state, was “50–70 percent” Communist and was “under operational control of the Communist party,” it’s founder claimed in 1961. Obviously academia and the news media were infiltrated, but the U.S. Chamber of Commerce also consisted of fellow travelers, and former Republican President Dwight Eisenhower had been an agent of the Kremlin, Birchers said. During the ’60s, the conspiracy came to be understood as extending well beyond commies—communism, according to the Birchers’ new line, was just one piece of a master conspiracy, a tool of a plot that stretched back to the 18th-century European Illuminati. For simplicity’s sake, Birch co-founder Robert W. Welch Jr., wrote in 1966, “let’s call this ruling clique simply the Insiders.”

Despite the John Birch Society’s extraordinary rise, it was effectively marginalized. The mainstream media did its part, but the decisive and telling rejection came from the elite right itself. Leaders of the conservative movement, still new and still actually conservative, worried that these noisy crackpots might ruin their chance at the nomination and presidency in 1964. In 1962, William F. Buckley met in Palm Beach, Florida, with the movement’s would-be candidate, Sen. Barry Goldwater. They resolved to take down the Birchers. For the next issue of his National Review, Buckley wrote a long hit piece, and Goldwater piled on in a letter to the magazine, condemning Bircher “views far removed from reality.”

The marginalization of the Birch Society didn’t stop true believers in that mad vision of a globalist conspiracy involving liberals and elites from multiplying.

Within three years, the fraction of Americans with an unfavorable view of Birchers, according to Gallup, went from a minority to a majority, and when Ronald Reagan ran for the California governorship in 1965, even he called them “kind of a lunatic fringe.”

The marginalization of the Birch Society and brand didn’t stop true believers in that mad vision of a globalist conspiracy involving liberals and elites from multiplying. Phyllis Schlafly’s 1964 polemic A Choice Not an Echo sold millions of copies. “Most of what is ascribed to ‘accident’ or ‘coincidence,’ ” she wrote, “is really the result of human plans.” The same year a Missouri GOP leader named John Stormer self-published None Dare Call It Treason, which explained how the federal government and the press and nonprofits were dominated by treasonous stooges and co-conspirators. None Dare Call It Treason sold millions of copies, softening the ground for another giant best-seller, None Dare Call It Conspiracy, published in 1972. “The conspirators come from the very highest social strata,” the authors explained. “They are immensely wealthy, highly educated and extremely cultured,” a conspiracy of “the Insiders,” “the elite of the academic world and mass communications media” intent on creating a “world supra-government.” The book sold 5 million copies.

This furiously, elaborately suspicious way of understanding the world started spreading across the political spectrum after the assassination of John Kennedy in 1963. But the shift in American thinking wasn’t registered immediately. In his essay “The Paranoid Style in American Politics,” published a year after the president’s murder, Richard Hofstadter devoted only a single sentence and footnote to JFK conspiracies, observing that “conspiratorial explanations of Kennedy’s assassination” don’t have much “currency … in the United States.” Elaborate paranoia was more of an established tic of the Bircherite far right, but because those folks fanatically despised Kennedy, they weren’t motivated to believe in a conspiracy to assassinate him.

In 1964, though, a left-wing writer published the first U.S. book about a JFK conspiracy, Who Killed Kennedy?, claiming that a Texas oilman had been the mastermind, and another JFK conspiracy book, Rush to Judgment by Mark Lane, a lawyer on the left, was a New York Times best-seller for six months in 1966. An American will to believe in all-powerful conspiracies spread and grew from the 1960s on, an invasive species that became a permanent feature of the American mental landscape, but finally more deeply and widely and consequential on the right. Hofstadter and many others have argued that the right is inherently more fertile ground for such paranoia. Maybe. In any case, only the American right has had a consistent, large, and organized faction based on paranoid conspiracism for six decades.

When Barry Goldwater was the GOP nominee in 1964, he had to play down his Bircher streak, but by the time he wrote his memoir With No Apologies in the 1970s, he felt free to rave on about the globalist conspiracy’s “pursuit of a New World Order” and impending “period of slavery,” the Council on Foreign Relations’ secret agenda for “one-world rule,” and the Trilateral Commission’s plan for “seizing control of the political government of the United States.”

Newly politicized Christian fundamentalists brought their own end-times conspiracism into the party. In the ’70s, a knock-around Texas evangelical named Hal Lindsey published The Late, Great Planet Earth, which purported to reveal the details of the evil über-conspiracy—how Satan and the Antichrist and false prophet and their minions in all their respectable disguises were taking over the world. For instance, the “beast coming up out of the sea, having ten horns” in the Bible was the new European Economic Community. The Late, Great Planet Earth was the best-selling nonfiction book of the entire decade.

One of the canonical texts in the modern revival of the fever-swamp conspiracist right appeared in 1991, a book called Behold a Pale Horse by a Southern California Navy vet and trade-school administrator named Bill Cooper. The book is a magpie collage of personal reminiscence, interconnected conspiracy theories, congressional transcripts, letters, newspaper articles, maps, and photos. “We have been taught lies,” Cooper wrote. “Reality is not what we perceive it to be.” The book’s title comes from Revelation, but its huge influence derived from its claims about a secret U.S. government alliance with extraterrestrials—a conspiracy theory that required no religious belief and was at the time itself becoming mainstreamed.

The ultimate puppet masters, according to Cooper, are the Illuminati. The master plan was “to invent an artificial threat from outer space in order to bring humanity together in a one-world government.” And everybody has been in on it—“the Jesuits, the Masons … the Nazi Party, the Communist Party … the Council on Foreign Relations … the Trilateral Commission, the Bilderberg Group, … the Vatican … Skull & Bones … they are all the same and all work toward the same ultimate goal, a New World Order” that “is beating down the door.” Plus the Federal Reserve, the CIA, and the United Nations. In fact, as Cooper noted, the masks were coming off—President Bush had started speaking openly about the plan to realize the Illuminati “dream of a new world order.”

At that moment, New World Order was becoming the all-encompassing catchphrase for people on the right who believed in a sinister conspiracy running the world, those elite entities named by Cooper as well as the ones—banks, news media, show business—that McCarthyists and the John Birch Society had identified in the 1950s. Previously, as political scientist Michael Barkun notes in his book A Culture of Conspiracy, New World Order beliefs had been “limited to two subcultures, primarily the militantly antigovernment right, and secondarily Christian fundamentalists concerned with the end-time emergence of the Antichrist. Their beliefs did not spread readily to outsiders. The extreme right constituted a pariah group whose viewpoints were systematically excluded from channels of mass communication and distribution.” Once belief in extraterrestrial visitors became “semi-respectable, a quasi-legitimacy was conferred,” which in turn “advanced the process by which conspiracism was becoming culturally sanitized … Ufology became … the vehicle for the New World Order to reach audiences otherwise unavailable to it.”

Only the American right has had a consistent, large, and organized faction based on paranoid conspiracism for six decades.

After the USSR and its empire finally fell apart in 1991, right-wing American conspiracists didn’t calm down or give up. Instead they imagined a larger, not-necessarily-communist conspiracy that required a fervent anti-faith in some monumental scheme of evil. That’s the delirious beauty of an overarching master conspiracy theory: Contradictory new facts, rather than undermining or disproving the scheme, are recast as affirmations of the undeniable larger truth.

Revelation-fixated Christians were ready to go. When Pat Robertson ran for the Republican nomination in 1988, he won four states. His politics were his theology and vice versa. His best-selling 1991 book The New World Order is essentially Behold a Pale Horse with more Christianity and no aliens: according to Robertson, the familiar conspiracy, running from the Illuminati to the Federal Reserve, was creating the satanic pre-Armageddon one-world government that Revelation predicted. Like Cooper (and probably not unlike Vladimir Putin), Robertson argued that the Illuminati contrived to make Russia communist so that 75 years later it would fail and thus become dependent on the Illuminati-run global financial system.

Now it was no longer just a few powerless crackpots in the patriot and militia movements who believed the United States was about to surrender to the tyranny of the New World Order. Newly unregulated talk radio was instructing a large constituency full time, while respectable politicians were galvanized by those true believers. Republican-led state legislatures passed bills demanding that Congress resist the New World Order. By the 1990s, the fear of a U.N. military takeover of the United States was so impassioned that the Indiana Department of Transportation was obliged to abandon its internal system for tracking the age of highway signs. Indianans had become convinced that colored dots on the backs of the signs were coded navigation instructions for the impending invasion by the U.N.’s armed foreigners.

In 1993, when a federal Bureau of Alcohol, Tobacco, Firearms and Explosives team arrived at the compound of a Seventh-day Adventist sect, the Branch Davidians, outside Waco, Texas, to investigate their arsenal of semi-automatic rifles, the Christians killed four agents. The FBI then conducted a siege and shootout in which the 75 Branch Davidians were killed. For millions of right-wing Americans, whether besieged patriots or persecuted Christians or both, this episode was a thrilling confirmation of every fear. The NRA began fundraising off the Waco siege, calling the ATF and FBI agents “jack-booted government thugs … wearing Nazi bucket helmets and black storm trooper uniforms.” The NRA had, in a generation, become a key Republican constituency and moved fully far right, adopting the extreme anti-government rhetoric of the militias and “patriot” groups. George H.W. Bush resigned from the NRA in protest, but as we now see, that unhinged anti-FBI conspiracism was the future of his party.

If in the past a White House deputy counsel had gone to a park across the Potomac from D.C. and shot himself in the head, it would’ve been a small, tragic two-day story. But in 1993, three months after Waco and six months into the administration of a president whom right-wing conspiracy theorists had already accused of being a cocaine trafficker, Vincent Foster’s “suicide” must have been a murder arranged by his old friends the Clintons as part of a conspiracy. This thinking was pervasive enough among Republicans that it took investigations by two different special prosecutors and two separate congressional committees in order to decide, officially, that Foster killed himself because he was depressed.

In 1996, the Republican Party’s platform started depicting the U.N. as a boogeyman. The 2004 platform demanded that “American troops must never serve under United Nations command,” but that document still had lots of references to the U.N.’s utility and importance—the last one that did. The 2016 GOP platform called for a constitutional amendment to protect homeschooling “from interference by states, the federal government, or … the United Nations.”

This is not just symbolic wankery. Take Agenda 21, for instance. In 1992, the U.N. held an Earth Summit to start getting everyone on the same page concerning the environment, especially on CO 2 emissions. It adopted a voluntary blueprint called Agenda 21, which nobody outside the environmental do-good sector paid any attention to for many, many years. From 1994 to 2006, there was exactly one reference to Agenda 21 in the New York Times.

But then the right discovered it—exposed it!—and refashioned Agenda 21 as a secret key to the globalist conspiracy. By 2012, Americans on the right knew to be scared, very scared, of this vague, 20-year-old international environmental plan. When the Obama administration created the White House Rural Council to promote economic development in places like Appalachia, a Fox News anchor warned that it was “eerily similar to a U.N. plan called Agenda 21, where a centralized planning agency would be responsible for oversight into all areas of our lives. A one-world order.” When Newt Gingrich was briefly the front-runner for the 2012 presidential nomination and mentioned it during a debate, applause prevented him from finishing the thought. At that moment, Glenn Beck had just published his dystopian novel, Agenda 21, and provided a perfect glimpse into the conspiracist mind on his TV show, where one of his Agenda 21 experts said, “You’re not going to find anything that isn’t Agenda 21 these days. … People recognize many, many things that are wrong but they don’t realize that they’re all connected.”

By then, conservative activists all over the country were using Agenda 21 as the scary catchphrase to defeat ordinary county and city land-use plans, carbon-emission information programs, plans for high-speed trains, traffic decongestion, bike lanes, and home energy meters. The Republican National Committee called it a “comprehensive plan of … global political control” including “socialist/communist redistribution of wealth.” A dozen Republican-majority state legislatures passed resolutions decrying Agenda 21.

The right had two generations to steep in this kind of conspiracism. Its exciting taboo vapors wafted more and more into the main chambers of conservatism, becoming familiar, seeming less outlandish. Do you believe that “a secretive power elite with a globalist agenda is conspiring to eventually rule the world through an authoritarian world government”? Yes, said 34 percent of the people who voted Republican in 2012.

There are loons on the left, too, of course, but the liberal establishment has simply never given its imprimatur to preposterous conspiracy theories, and research about belief in dubious conspiracies confirms that there are many more fervid American conspiracists on the right. And take a look around today’s John Birch Society website: Its concerns and spin—leaving the U.N., Agenda 21 alarmism, fighting “amnesty” for undocumented immigrants—are now unremarkably Republican.

Among the clearest recent evidence for just how deeply fringe conspiracy theories have infected the mainstream right, just consider birtherism, and Americans’ fear of sharia law, and the conspiracymonger the country elected president in 2016.

Right before we elected our 44th non-Muslim president in a row, people on the right began fantasizing that American Muslims were about to pull off a scheme to supplant U.S. jurisprudence with Islamic jurisprudence. The definitive text is a 2010 book called Shariah: The Threat to America. Its 19 authors included respectable hard-right conservatives and national security wonks. We’re “infiltrated and deeply influenced,” the book says, “by an enemy within that is openly determined to replace the U.S. Constitution with shariah.” The movement took off, and in short order the specter of sharia became a right-wing catchphrase encompassing suspicion of almost any Islamic involvement in the U.S. civic sphere. The word gave Islamophobia a patina of legitimacy.

The co-inventor of the fantasy and the ringleader and front man of Shariah: The Threat to America was Frank Gaffney, who’d been a Pentagon official in the Reagan administration. Gaffney claimed that Saddam Hussein’s regime was behind the 9/11 attacks—and that it had recruited Timothy McVeigh to bomb the Oklahoma City federal building. Gaffney also became obsessed with his fantasy that the conservative anti-tax lobbyist Grover Norquist is a covert agent of the Muslim Brotherhood. As soon as Obama got elected, naturally, Gaffney was referring to the “mounting evidence that the president not only identifies with Muslims, but actually may still be one himself.” None of this got Gaffney excommunicated from the 21st-century right.

The anti-sharia movement successfully lobbied states to pass statutes and constitutional amendments banning the use of sharia in their courts and legal systems, a fantasy solution to an imaginary problem, almost like a government plan to prevent a zombie apocalypse. And when candidate Trump first announced his proposed ban on Muslim immigrants—because sharia “authorizes such atrocities as murder … beheadings”—his backup data consisted entirely of bogus polling by Frank Gaffney.

Why do half of Republicans—and two-thirds of Trump’s primary voters—remain convinced that Barack Obama is a Muslim? Because GOP elected officials and conservative leaders encouraged them for more than a decade. Trump launched his political career by embracing a conspiracy theory twisted around two deep American taproots—fear and loathing of foreigners and nonwhites. In 2011, he made himself chief spokesman for the fantasy that President Obama was born in Kenya, a fringe idea that he single-handedly brought into the mainstream. House Republicans co-sponsored a federal bill that would require presidential candidates to submit birth certificates and other proof that they aren’t secret foreigners. After the Hawaiian bureaucrat who released a copy of the president’s birth certificate died in a private plane crash, Trump tweeted: “How amazing. … All others lived”—suggesting the official had been murdered by the Obama conspiracy. Finally, in the fall of 2016, he grudgingly (and temporarily) admitted the president was indeed a native-born American—at the same moment that an Economist/YouGov survey found a majority of Republicans believed that Obama was probably or definitely born in Kenya.

“Scalia,” the right-wing radio host Michael Savage asked candidate Trump in 2016, “was he murdered … ?” Well, Trump replied, “they say they found the pillow on his face, which is a pretty unusual place to find a pillow.” On Fox and Friends, Trump discussed, as if it were fact, the National Enquirer’s suggestion that Ted Cruz’s father was connected to JFK’s assassination. “What was he doing with Lee Harvey Oswald shortly before the death, before the shooting? It’s horrible.” The Fox News anchors interviewing him neither challenged nor followed up. Trump revived the 1993 fantasy about Vincent Foster—his death, Trump said, was “very fishy,” because Foster “had intimate knowledge of what was going on. He knew everything that was going on, and then all of a sudden he committed suicide. … I will say there are people who continue to bring it up because they think it was absolutely a murder.” He has also promised he’s going to make sure “you will find out who really knocked down the World Trade Center.”

Does Trump really think he lost the popular vote because of a conspiracy that arranged for millions of noncitizens, “illegals,” to vote for Clinton? “I’m a very instinctual person,” President Trump said when a Time reporter challenged him on this claim, “but my instinct turns out to be right.” Did he really think President Obama ordered his telephones to be tapped and that a conspiracy of government officials covered it up? According to the New York Times, the people around Trump say his baseless certainty “that he was bugged in some way” in Trump Tower is driven by “a sense of persecution bordering on faith.” And indeed, their most honest defense of his false statements about conspiracies has been to cast them practically as matters of religious conviction—he deeply believes this stuff, so … end of story.

This is exactly what Sean Spicer did concerning the nonexistent 3 million to 5 million illegal voters: In a single encounter, he earnestly reminded reporters that Trump “has believed that for a while” and “does believe that” and “it’s been a long-standing belief he’s maintained” and “it’s a belief that he has maintained for a while.” Which must be why a quarter of Americans subscribe to that preposterous belief themselves. And in Trump’s view, that overrides any requirement for facts.

“Do you think that talking about millions of illegal votes is dangerous to this country without presenting the evidence?” the ABC World News Tonight anchor asked President Trump right after his inauguration.

“No,” he replied, “not at all! Not at all—because many people feel the same way that I do.”

Since then, of course, Trump has fired the FBI director and pushed out the deputy director, provoked a special counsel’s investigation, and conjured an anti-Trump conspiracy at the bureau—which of course many on the right now believe, with help from members of Congress and the Sean Hannitys of the world. Republicans by almost 2 to 1 disapprove of Robert Mueller’s work, and nearly half of them say they now have “not very much” or no confidence at all in the FBI. In other words, our first conspiracy theorist in chief is harnessing his party’s old conspiracist tic, originally Kremlin-focused, to discredit the existence of an actual anti-American conspiracy hatched in the Kremlin. History is filled with tragic ironies, and this is a colossal one.