DES MOINES — Maybe Beto O’Rourke knew, on some level, that this was never quite right.

Most politicians look in the mirror and see a president. It is possible — not certain, but possible — that Mr. O’Rourke was not among these until less than a year ago, long before the punk-rock-congressman-turned-Democratic-savior became a White House also-ran.

He had lost a Senate race in Texas with dignity, no small thing, and smart people — Barack Obama people, the kind who should have known — were telling him he had what it took, what the others lacked, what the nation so desperately needed.

He started thinking. He felt “stuck,” he wrote in January, “in and out of a funk.” He drove himself around the country a little. The phone wouldn’t quit. He let the tease linger. He was coy onstage with Oprah Winfrey. It was happening. Wasn’t it? Nobody strings Ms. Winfrey along and turns back. O.K., he was doing it. But why was he doing it? He would sort that out in time.

“Man, I’m just born to be in it,” Mr. O’Rourke said, infamously, in a March cover interview with Vanity Fair, which, with the benefit of hindsight, sounds less like a boast than a bit of self-deception.