People are weak. They are susceptible. They are easily manipulated through their fears. They long to prostrate themselves. They can be led by the nose into the gutter. The angels of their better natures, if they’ve ever given a moment’s thought to them, are a lot less powerful than the devils of their diabolical urges.

They lie, they exploit, they seek distraction at any price from the monotony of existence. The life of humankind, as Hobbes famously put it, is “solitary, poor, nasty, brutish, and short.” Especially short: You no sooner begin to get the hang of it, learn a few useful tricks like lowered expectations, than it’s over. Poof!

This is the basic setup. Society is an exercise in trying to offset horrors through law and convention.

Every now and again, along comes somebody, or some new technology, or both, capable of taking this raw human material and shaping it into a crazed, baying, hypnotized mob that is convinced the Great Leader has come. Whatever this Messiah says goes. The moon is a balloon, if he says so; and entire communities with the wrong beliefs or shade of skin are chopped liver.

Examples? Dear reader, I respect you too much to belabor the obvious. Look around. The wealthiest society on earth is currently subjected to the chaotic rule of a mean and vulgar charlatan who refined the manipulation of humanity through a TV show that was a ratings smash in its first season, continued under his guidance for more than a decade, and relied on the cruelty of whimsical humiliation for its frisson. Donald Trump had a solid education in the power of images, the flimsiness of objective reality, and the magnetism of authority.

“I could stand in the middle of Fifth Avenue and shoot somebody and I wouldn’t lose any voters, O.K.?” he declared during the campaign. Let’s hand it to Trump: he was right. Americans voted him into office after he said that. They were ready to roll the dice, even on nuclear war, if the alternative was to be bored. They were mad.

There’s not much new under the sun. Long before Facebook and Twitter and Russian trolls on social media, the potential to combine the bombardment of visual media, the “genius” of an individual (Trump’s word), and mass disorientation to forge dystopian madness had been imagined.

So here’s a little test. The following three passages are not in chronological order. Which came first, and when do they date from?

“We deal in illusions, man! None of it is true! But you people sit there, day after day, night after night, all ages, colors, creeds. We’re all you know. You’re beginning to believe the illusions we’re spinning here. You’re beginning to think the tube is reality and that your own lives are unreal. You do whatever the tube tells you.”

Here’s the second: “This whole country’s just like my flock of sheep! Rednecks, crackers, hillbillies, hausfraus, shut-ins, pea-pickers — everybody that’s got to jump when somebody else blows the whistle….. They’re mine. I own ’em. They think like I do. Only they’re even more stupid than I am, so I gotta think for them.”

And finally: “The stresses set up by the social changes wrought by the advent of technology are straining the structure of civilization beyond the limits of tolerance. The machine does our work for us and meekly comes and goes at our bidding. But it inexorably demands its wages.”

The answers are: the first dates from 1976 and is from the extraordinary Sidney Lumet movie “Network,” written by Paddy Chayefsky. The second, from 1957, appears in the equally prescient Elia Kazan movie “A Face in the Crowd,” written by Budd Schulberg. (Watch them both if you want to understand Trump.) The third dates from 1938. It’s a passage from my father’s high school magazine in Johannesburg that I stumbled on while researching my last book. “Civilization,” of course, would collapse a year later when Hitler invaded Poland.

“Network” traces the apotheosis of a news anchor, Howard Beale, who goes off-script on TV, raging against the world and television — their lies and manipulations — and develops a following with his unforgettable cri de coeur: “I’m as mad as hell, and I’m not going to take this any more!” His ratings, previously in a dive, soar. “A Face in the Crowd” also follows a media sensation, Lonesome Rhodes, who parlays his charm and popular touch into a meteoric rise to national television. He is a fraud, with startling instincts for human weakness, who takes everyone in.

Beale, whose rise begins when he announces he will commit suicide live on TV, succumbs in the end to the terrible logic of his success when he is assassinated during his show.

Rhodes is undone by a hot mic as he dissects the idiocy of the Americans he has entranced: “Those morons out there? Shheh, I can take chicken fertilizer and sell it to ’em for caviar. I can make them eat dog food and they’ll think it’s steak ... You know what the public’s like? A cage full of guinea pigs."

Somewhere, a hot mic is waiting for Trump. Its name might be the Mueller investigation, whose painstaking nature is making him hotheaded. People are dumb, but they know when their president is compromised. As a wise man once observed, “You can’t fool all the people all the time.”

<ROGER COHEN>