How could Donald Trump's campaign possibly still be alive, given all of the impolitic things he's said? The Post's Chris Cillizza has the answer. (Tom LeGro/The Washington Post)

Donald Trump is pure political id.

I’ve described the reality TV star and front-runner for the Republican presidential nomination in lots of different ways over the past few months — a car-accident candidate, the middle finger of the Republican base — but I think this one fits him best.

Trump does and says whatever he feels like doing or saying in the moment. He doesn’t reflect. He doesn’t second-guess. And he most certainly doesn’t apologize.

His decision in Thursday’s GOP presidential debate to attack Fox News host Megyn Kelly over a question concerning his past comments about women perfectly illustrates Trump’s unchecked id.

After attempting to deflect the question with humor — he said he had made derogatory comments only about comedian Rosie O’Donnell — Trump went all in on Kelly. “Honestly, Megyn, if you don’t like it, I’m sorry,” he said. “I’ve been very nice to you, although I could probably maybe not be, based on the way you have treated me. But I wouldn’t do that.”

In the aftermath of the debate, Trump kept up the barrage — because why not? — at one point re-tweeting someone who described Kelly as a “bimbo.” He followed that up with the now-infamous “blood” comments.

All of which brought us to Sunday morning and a barrage of Trump appearances on the talk shows in which his all-id-all-the-time philosophy was on full display.

Asked whether he should apologize to Kelly, Trump told NBC’s Chuck Todd: “There’s nothing to apologize” for.

When the “Meet the Press” host pressed Trump on whether he was referring to Kelly’s menstruation cycle with the “blood” comment, the candidate responded: “Hey, I went to the Wharton School of Finance, the toughest place to get into. I was a great student. I don’t talk that way.”

About his treatment of women more generally, Trump told Todd: “When I was attacked viciously by those women, of course, it’s very hard for them to attack me on looks, because I’m so good-looking.”

I rest my case.

Look, Trump’s embracing of his id has, to this point, paid tremendous political dividends. He has successfully cast his willingness to say what he thinks at all times as a sort of anti-political correctness that quite clearly appeals to a decent chunk of the Republican electorate.

Listen to any Trump supporter talk and you hear some variation of this: He’s not beholden to anyone. He’s not like all those other politicians. He says what we’re all thinking.

There is no doubt an aspirational appeal to someone like Trump. Wouldn’t it be nice to have enough money to tell everybody you meet exactly what you think of them? Or do whatever you wanted at all times?

He can and he does. And people — or at least some people — admire it.

The problem is that a candidate who is all id will struggle to sustain himself in an extended campaign.

Doing and saying whatever you want is great, but it’s not a strategy. Or even, really, a message. What began with Trump’s outspokenness on immigration — an issue that carries real resonance within the Republican base — has transformed into Trump’s outspokenness on whoever is standing in front of him, most of whom are “total losers.”

In just the past 24 hours leading up to Sunday afternoon, Trump has attacked Kelly, Fox News’s Chris Wallace, GOP presidential rivals Jeb Bush and Carly Fiorina, the news media and former consultant Roger Stone — among many others. “When I’m attacked, I fight back,” Trump told Todd.

But name-calling isn’t a platform on which to run for president. And if Trump thinks treating people the way he does would somehow translate into international diplomacy, there’s scads of historical evidence to suggest that he’s wrong.

Doing whatever you want all the time sounds fun. Like when you’re a teenager and your parents go out of town. The first party you throw is AMAZING. But by the fourth night you probably would rather sit and watch a movie by yourself than throw another rager.

The question for Trump is how his all-id campaign wears on voters over time. What can feel refreshing and revelatory one day can feel mean and pointless if repeated every day.

For Trump to sustain his success, he’d almost certainly have to show that he is more than just brashness and boisterousness. He would have rein in his id — at least somewhat. But judging from Thursday’s debate and the 72 hours of I-do-what-I-want-ness that have followed it, that seems a very unlikely prospect.