I never thought Donald Trump would run for president. If he did run, I didn’t think he would gain any support, and if he did gain any support, I didn’t think it would last. I thought all polls would show him being crushed by Hillary Clinton.

Fall is upon us, and Trump is leading in Iowa, leading in New Hampshire, leading all Republicans nationally. He has roughly double the combined support of Jeb Bush and Marco Rubio.

In a general election match up against Hillary Clinton, he’s only 2.8 points behind, according to a RealClearPolitics polling average late last week, and doing about the same as Bush and Rubio.

I don’t have much skull left in the spot where I’ve been scratching my head because, as a conservative, I fail to see how Trump is anything but a flaming liberal compared to Bush, Rubio and every other Republican candidate.

As a patriot, I’m shocked that Trump got away with slandering John McCain for his Vietnam ordeal. As a person who has a face, I can’t believe he stooped to attacking Carly Fiorina’s.

So this time I’ll try something different: imagining what it’s like to be a Trump supporter. What’s the appeal?

I think I can answer in one word: Stones. Cojones. His buildings aren’t the only things he owns that are thickly layered in brass (and, probably, emblazoned with the Trump logo.)

There seems to be a large contingent of Americans who aren’t particularly interested in Trump’s vague policy prescriptions.

Try to get Donald to talk specifics and you get a level of analysis much like that of Ox, whose senseless history report in “Bill and Ted’s Excellent Adventure” drew raucous applause by devolving into micro-tribalism: “Everything is different, but the same…things are more moderner than before…bigger, and yet smaller…it’s computers…San Dimas High School football rules!”

Substitute in “American industry rules!” and you’ve more or less got a Trump “speech,” or rather riff, since he keeps winging it.

“Imagine what it’s like to be a Trump supporter. What’s the appeal?”

Here is how the man responded to a question about God. “Well, I say God is the ultimate. You know, you look at this? Here we are on the Pacific Ocean. How did I ever own this? I bought it 15 years ago. I made one of the great deals, they say, ever. I have no more mortgage on it, as I will certify and represent to you. And I was able to buy this and make a great deal. That’s what I want to do for the country: Make great deals. We have to, we have to bring it back. But God is the ultimate.”

Trump supporters frequently mention that they love his political incorrectness. Trump says things you just can’t say anymore. No. 1 on that list has to do with immigration.

Even to hint that mass legalization of illegal immigrants will encourage more lawbreakers, while exerting downward pressure on the wages and job opportunities of working-class Americans, is labeled xenophobia or worse. Trump isn’t afraid to say this, and say it loudly.

But Trump isn’t a single-issue candidate. Immigration, trade, health care — they’re all part of an overall vision of America. America today is sagging, flaccid, impotent. He’s got just what it takes to make America stand up straight and tall.

Can this be accomplished by wearing a truck-stop foam baseball cap that says “Make America Great Again”? I have my doubts. But he’s the only candidate on either side of the aisle who even seems to care about American greatness.

Seventy-two percent of Americans think the country isn’t as great as it once was, and the other candidates all seem to be chatting in the bar car as the national choo-choo slides off the rails and heads for the canyon. Only one man is screaming and waving his arms.

Trump’s complete lack of preparation for our highest office isn’t registering to his supporters: Every moment that looks clownish to someone versed in policy looks refreshingly unscripted to Trump fans.

It isn’t the details that they want to hear about, it’s the attitude — aggressive, confident, tough, bold. He screams leader, not wonk.

Next to Jeb Bush, who actually has political experience, conservative principles and specific policy solutions, all of which the Donald lacks, Trump looks like the varsity quarterback giving a noogie to the debate-club nerd.

You can’t begin to fix the problem until you admit that there is a problem, and what looks like grandstanding and content-free demagoguery to me looks to many citizens like an urgently needed passion.

The average American feels that the country has a sucking chest wound and everybody but Dr. Trump is telling him to treat it with a couple of aspirin.