“In your guts you know he’s nuts.”

As we watch the steady unhinging of President Donald Trump, it’s time to remember that chant from the 1960s.

When it was coined in 1964 the slogan wasn’t directed at a president, but at the Republican presidential candidate, Senator Barry Goldwater of Arizona.

Lyndon Johnson was then an unelected president seeking election, having stepped into the shoes of the slain John Kennedy and pledged himself to creating the Great Society—partly to honor Kennedy’s agenda and partly to immortalize his own greatness as a can-do legislator.

There surely never was a more bipolar choice than Johnson and Goldwater. And Goldwater deliberately ran on that difference: “extremism in the defense of liberty is no vice” was his rallying cry.

We were then only two years out from the Cuban Missile Crisis, when the world came closer to a nuclear Armageddon than at any other time—and closer than anyone realized while it was happening.

But the Johnson campaign couldn’t believe its luck. Goldwater backed up his claim to extremism by advocating the dropping of a “low yield” atomic bomb on the Chinese supply lines to the communists of North Vietnam. He called in John Wayne as a surrogate in commercials to stress his warrior virility. And he said, “Sometimes I think the country would be better off if we could just saw off the Eastern Seaboard and let it float out to sea.”

As it turned out, some guys on that Eastern Seaboard, at the hip Manhattan advertising agency Doyle Dane Bernbach, were to be his nemesis. They grabbed at Goldwater’s readiness to use nukes by producing one of the most legendary campaign ads of all time, the so-called “Girl with the Daisy.”

An adorable three-year-old girl was seated in a field of daises picking her way through petals, counting them as they fell. This countdown merged with the countdown of an intercontinental ballistic missile being fired up and launched.

At the end of the countdown a close-up of the girl’s eyes dissolved into the mushroom cloud of an atomic blast as lines from a Johnson campaign speech played over it: “These are the stakes, to make a world in which all of God’s children can live, or go into the dark. We must either love each other or we must die.”

The ad ran only once. There was an outcry—quite justified—that it exaggerated Goldwater’s hawkishness. But once was enough to make it go viral, long before the phrase entered the lexicon. The network news shows re-ran it as they reported on the controversy and Time magazine put the girl on the cover.

Goldwater’s own TV ads all had the punchline “In your heart you know he’s right.” After the Girl with the Daisy episode Democratic wags added to the message by spreading the “you know he’s nuts” version, to much amusement. Johnson won by a landslide.

But behind that seemingly flippant line lay something really serious that was taking hold in the American psyche—the fear of a deeper and long foretold threat, of an authoritarian despot ending up in the Oval Office.

And now that that has finally happened we should ask ourselves: Who has most consistently tried to alert us to this outcome?

Not the judiciary, not the Congress, and not the news media—but Hollywood. This is arguably the outstanding example of a rare moment when popular culture discovered a gripping narrative that’s also a powerful warning of future dangers to the republic.

In some of Goldwater’s commercials he comes across in tone and text eerily like the villain of one of that year’s best movies, the wonderfully named General James Mattoon Scott, played by Burt Lancaster, in Seven Days in May. Scott, chairman of the joint chiefs of staff, is the ringleader of a covert military plot to replace a liberal president with a ruthless anti-communist hawk—Scott himself.

Seven Days in May was written by Rod Serling, based on the book by two reporters, Fletcher Knebel and Charles W. Bailey, who covered the Cuban Missile Crisis for Look magazine.

They had seen President Kennedy and his brother Robert, the attorney general, weigh how to react to the discovery that the Soviets had based nuclear-tipped missiles in Cuba, within striking distance of large swathes of the United States. Hawks in the Pentagon, led by the Air Force chief Curtis LeMay, wanted to bomb the bases and thought the Kennedys were not manning up but showing weakness that Moscow would exploit.

The Kennedys realized that one false step would inevitably end in a nuclear war. Robert Kennedy recalled: “I thought, as I listened, of the many times I had heard the military take positions which, if wrong, had the advantage that no one would be around at the end to know.”

In the event the Kennedy gamble, that a naval blockade of Cuba would force the Soviets to back down, worked—but only at the last minute and after Kennedy secretly agreed with the Soviet leader, Nikita Khrushchev, to remove U.S. nuclear missiles from Turkey.

John Frankenheimer, the director of Seven Days in May, said that the Kennedys, through their press secretary Pierre Salinger, had urged that the film be made against advice from the Pentagon because it described a scenario, a military coup, that might actually happen.

Frankenheimer was also the director of the mother of all presidential conspiracies, the 1962 movie The Manchurian Candidate in which the plot is not a right-wing coup but a communist conspiracy to plant a pliant puppet in the White House.

This is to be done by means that even Vladimir Putin could never have orchestrated, though he might well admire, involving an oedipal relationship played out on screen with a creepy reality by Angela Lansbury as the mother and Laurence Harvey as a son programmed to be an assassin.

This time the writer was the prolific political satirist Richard Condon, who declared that “Every book I’ve ever written has been about abuse of power… I would like people to know how deeply their politicians wrong them.”

In the early 1960s those fears of overarching power were always played out against the specter of the mushroom cloud. The Cold War strategy of mutually assured destruction, MAD, was sufficiently unnerving to amp up the horrors of any presidential conspiracy, whether it was neo-fascist or communist. And that was the theme of Stanley Kubrick’s satirical masterpiece of the decade, Dr. Strangelove.

A rogue Air Force general initiates a nuclear strike on Russia and makes sure it can’t be aborted by the standard safety procedures. This throws both the Russian and American leaders into an urgent alliance to avert catastrophe. Three of the main characters, the American president, a British air force officer and Strangelove himself, a demented ex-Nazi nuclear strategist, are played by Peter Sellers.

Rather than suggest a wider conspiracy, Kubrick and the two writers, Terry Southern and Peter George, set out to show how easily the sum of all our fears could unfold through the actions of one all-too-plausible maniac. In a way, that makes it much more scary.

But it is a figure from 1979 who suddenly steps from a movie to become a precursor of our current gallery of White House grotesques: Chauncey Gardner, in the Hal Ashby movie Being There.

In this hilarious but also very dark comedy an idiot savant gardener named Chance glides, bemused, through a wave of accidental encounters until he ends up giving economic advice to a president. Confusion over his name and vocation produces his new identity, Chauncey Gardner, a man totally unequipped to be a potted plant, let alone a president and yet who, when the president dies, becomes a candidate to replace him.

This destiny emerges only in the movie’s final scenes, where a casket containing a deceased president is carried to a mausoleum. In audible whispers the pallbearers, all members of the president’s inner circle, decide that Chauncey, despite being a simpleton, should be installed in office because his TV ratings went through the roof.

Those ratings were achieved on the basis of a primetime appearance in which, using the only kind of knowledge he possesses as a metaphor, Chauncey appears to be reassuring the nation that the economy, like a bush, will “show growth in the spring.”

As it happened, Chauncey was the creation of two deeply troubled people.

The movie is based on a 1970 novel by Jerzy Kosinski, and also written by him. Late in his life Kosinski was accused of faking an autobiographical account of growing up in Poland as a fugitive from the Holocaust in a much-praised book, The Painted Bird. He killed himself in 1991, leaving that dispute and other parts of his racy social life to be argued over without conclusion.

Chauncey is played by Peter Sellers. As he demonstrated in Dr. Strangelove with his multiple roles, Sellers was a masterful chameleon, able to take on every nuance of a character, from the cold sober to the utterly deranged.

Unfortunately, to those who knew him, the one thing Sellers could not be was a real person. One of his earliest directors, who acknowledged his comic genius, said, “He is a friend to nobody. I think he is a human being who has need of friendship but whose great tragedy is that he is incapable of the real sacrifices that flow from deep friendships.”

Perhaps it takes people as personally anguished as Kosinski and Sellers to invent such a convincingly accidental celebrity as Chauncey Gardner, who has turned out to serve as an uncanny predictor of how far the engine of celebrity can now take an entirely fabricated personality to the heights of power.

However, it has to be admitted that the villains produced by our paranoia in the ’60s and ’70s seem comparatively simple now in their characterizations. They don’t anticipate the sheer crazy velocity of a Twitter-driven news cycle commanded by a president.

Nor did those movies prepare us for the way this travesty of governance would be accepted so easily: Through the complicity of the Republican Party and through a wider collective apathy in the face of legislated bigotry and racism that echoes that of Germany in 1933.

In our brain we know he’s insane—but who is ready to deal with that, and how?