Her careful cramming and his cocky hamming tell you all you need to know

Before this week’s presidential debate, Vice President Kamala Harris holed up. Hunkered down. Studied. Practiced. Her advisers made no secret of that. I read dozens of articles about it.

Donald Trump? He reportedly did some preparation. Nothing too arduous. Or at least that was the message put out by his people, who know that he sees himself, and likes to be seen, as someone nimble enough to wing it, a peacock unmoved and unbound by the conventions that lesser birds obey.

Hurray for him. Actually, hurray for her. Harris had the better night by far, and it was partly because she did her homework, as I observed in an analysis of the debate published just a few hours afterward.

But what I didn’t take proper note of — and what all of us scribes and pundits too infrequently acknowledge — is what that says about a person. How important a barometer of her professionalism and character it is.

In fact, we often dismiss or even degrade all the cramming that candidates do by branding their performances “rehearsed,” as if anything that isn’t spontaneous isn’t sincere. As if real talent requires no tending. As if careful planning is inferior, even antithetical, to true inspiration.

Wrong. It reflects contenders’ respect for the positions or promotions they’re seeking. It communicates their lack of pure entitlement. It affirms a crucial ration of humility and an equally important measure of discipline: They accept the need both to work for what they want and to polish themselves in the service of it.

Besides, such polishing bears fruit. Harris frolicked in an orchard of it during the debate, dominating Trump by dint of juicy anecdotes, ripe details, plum facts.

When she mentioned how many high-ranking alumni of his administration had denounced him, she gave example after example. When she called out his inconstancy on abortion rights, she named the flips and nailed the flops. When she questioned his diplomatic dalliance with the Taliban, she made an episodic narrative of it.

And she was able to provoke him into rages, time and again, because she’d gathered the receipts and plotted their presentation. “Rehearsed” is indeed one word for that. “Smart” is another.

Foolish is what Trump did: take the stage in Philadelphia with a surplus of smugness and a deficit of knowledge. He has been a presidential candidate, a presidential critic or the actual president for the past nine years, but when he and Harris discussed how health care might be improved, he said he hadn’t figured it out yet: “I have concepts of a plan.” I guess those are like my inklings of the novel that I’ll apparently never get around to writing. The difference is that I’m not asking for the National Book Award, while he’s demanding the helm of the most powerful nation on Earth.

Trump seems to think that there’s some ingenious scheme or meaningful valor in improvisation, when there’s really just laziness, arrogance and a likely path to humiliation, which was his richly deserved destination on Tuesday night. Because he had not matched Harris’s preparation, he could not rival her cool. Because he couldn’t prosecute her with the volume of evidence that she toted into their confrontation, he resorted to schoolyard jeers.

Harris, he sputtered, is the worst vice president ever! And Joe Biden is the worst president! “And you know what?” Trump said. “I’ll give you a little secret. He hates her. He can’t stand her.” I half expected his next sentence to be a proclamation that she has cooties. It would have been no less puerile than most of the rest of his babble.

Someone who approaches a pivotal moment in an agonizingly close election with such a cocksure and cavalier attitude won’t tackle the presidency with any more gravity and dignity. Someone who treats that critical juncture as an opportunity demanding a muscular effort has much greater promise. Whatever Harris’s mix of strengths and weaknesses, she’s a serious person. Trump is a frivolous and contemptuous one.

Frank Bruni is a NY Times opinion writer and Duke University professor of journalism and public policy at Duke University.