I spent a long, awkward weekend with Donald Trump in November 1996, an experience I feel confident neither of us would like to repeat.

He was like one of those characters in an 18th-century comedy meant to embody a particular flavor of human folly. Trump struck me as adolescent, hilariously ostentatious, arbitrary, unkind, profane, dishonest, loudly opinionated, and consistently wrong. He remains the most vain man I have ever met. And he was trying to make a good impression. Who could have predicted that those very traits, now on prominent daily display, would turn him into the leading G.O.P. candidate for president of the United States?

His latest outrageous edict on banning all Muslims from entering the country comes as no surprise to me based on the man I met nearly 20 years ago. He has no coherent political philosophy, so comparisons with Fascist leaders miss the mark. He just reacts. Trump lives in a fantasy of perfection, with himself as its animating force.

Before I met him back in 1996, I felt bad for him. He’d had a rough 10 years. He had just turned 50 and wasn’t happy about it. He looked soft, from his growing jowls to the way his belt bit deeply into the spreading roll of his belly. As a businessman he had crashed and burned, rescued only by creditors who had to bail him out lest they be dragged down with him. His enterprises were being run by court-appointed managers, who had put him back on his financial feet mostly by investing heavily in Atlantic City, which was then on the rise.

He had insulated himself from failure with bluster. In public he was still The Donald—still rich, still working hard at being a symbol of excess. I was working on a profile of him for Playboy, which was his kind of magazine. He considered himself the magazine’s beau ideal, and was inordinately proud of having been featured on the magazine’s cover some years before. His then wife, Marla Maples, told him, sardonically, that he ought to buy the magazine: “You bought the Miss Universe Pageant; it’s right up your alley.” He must have figured it was a safe bet to agree to cooperate for my story. But well before I left him, we both knew he probably wouldn’t like the final product.

I was prepared to like him as I boarded his black 727 at La Guardia for the flight to Mar-a-Lago, his Florida home—prepared to discover that his over-the-top public persona was a clever pose. That underneath was an ironic wit, an ordinary but clever guy. But no. With Trump, what you see is what you get. His behavior was cringe-worthy. He showed off the gilded interior of his plane—calling me over to inspect a Renoir on its walls, beckoning me to lean in closely to see . . . what? The luminosity of the brush strokes? The masterly use of color? No. The signature. “Worth $10 million,” he told me. Time after time the stories he told me didn’t check out, from Michael Jackson’s romantic weekend at Mar-a-Lago with his then wife Lisa Marie Presley (they stayed at opposite ends of the estate) to the rug in one bedroom he said was designed by Walt Disney when he was 18 (it wasn’t) to the strength of his marriage to Maples (they would split months later).

It was hard to watch the way he treated those around him, issuing peremptory orders—“Polish this, Tony. Today.” He met with the lady who selected his drapery for the Florida estate—“The best! The best! She’s a genius!”—who had selected a sampling of fabrics for him to choose from, all different shades of gold. He left the choice to her, saying only, “I want it really rich. Rich, rich, elegant, incredible.” Then, “Don’t disappoint me.” It was a pattern. Trump did not make decisions. He surrounded himself with “geniuses” and delegated. So long as you did not “disappoint” him—and it was never clear how to avoid doing so—you were gold.