“Jonah — We have come a long way together — and I like it! Thank you!”

That right there is the full extent of my personal communications with Donald J. Trump. He wrote it by hand in broad felt pen on the very page my column appeared in the New York Post, mostly in ALL CAPS, followed by his signature (which looks a bit like an EKG reading). It came to me as a PDF via email on Sept. 4, 2015, under the subject header “From the office of Donald J. Trump.”

Apparently he does this sort of thing a lot. I know several other columnists who've received similar missives from the GOP nominee. But I like mine the best. It came after months of feuding with Mr. Trump. We had an epic battle on Twitter in which he insisted I should be fired. He told an NBC reporter that I don't know how to buy pants. (I'm still trying to figure that one out.) But, in my column, I had given Mr. Trump a backhanded compliment.

I noted that according to the polls, the No. 1 thing his fans liked about him was that he “tells it like it is.” I disagreed with that then — and now. (I think he makes stuff up on the fly, which is different.) But I did concede that Mr. Trump was refreshingly unfiltered. “The one thing you can be sure of,” I wrote, “is that he hasn't consulted with a political consultant about how to talk.”

My theory was that Mr. Trump, a bridge-and-tunnel populist with a chip on his shoulder, never cared what the muckety-mucks at The New York Times, Washington Post, Los Angeles Times or even the pinheads at National Review (where I'm a senior editor) thought about him, so long as they wrote about him.

“I'd be willing to bet that if there's a single newspaper in the country that Trump cares about, it's the New York Post,” I wrote. “The Big Apple Narcissus has spent his entire career looking for his reflection on Page Six of New York's true paper of record.”

And that's why I loved Mr. Trump's missive. Oblivious to the irony, The Big Apple Narcissus proved my point perfectly.

I have no idea whether or not he thought his mash note would win me over. But I'm glad it didn't. Because it seems that whenever people put their faith in Mr. Trump, he sets out to punish them for it.

For 18 months he promised to “pivot” and become presidential. But once he secured the nomination, he vowed he wouldn't change. Just hours after Paul Ryan endorsed him, Mr. Trump doubled down on his bigoted attacks against an American judge of Mexican descent. After rising in the polls for a while, Mr. Trump started his verbal war on the parents of a slain Muslim-American soldier.

Last week, a group called “Scholars & Writers for Trump” issued their endorsement of the GOP nominee. One of the group's leaders, law professor F.H. Buckley, wrote, “I have some sympathy for people who can imagine a better Republican candidate this year, but from the very beginning I always thought that Donald Trump was perfect.”

Two days later, Mr. Trump the Perfect was tweeting at 3:20 a.m. about Alicia Machado, the Miss Universe he humiliated 20 years earlier. At 5:30 a.m., he instructed his millions of followers to check out her nonexistent “sex tape.”

These are just a few of the highlights. When he announced Indiana Gov. Mike Pence as his running mate, he couldn't be bothered to stand next to him on stage at their initial press conference. In their joint interview on “60 Minutes,” Mr. Trump treated Mr. Pence like he was an unwanted intern. Poor Chris Christie has been abused like a valet in the court of the Romanovs.

The man is so incapable of taking advice, his aides have started leaking constructive criticisms to the press. A beleaguered Newt Gingrich had to go on “Hannity” the other night and essentially beg a man he's favorably compared to Reagan, Thatcher and Churchill to stop the nighttime tweeting. “There's no excuse. Ever.”

It's all for naught. Even if the New York Post itself blared on its cover “Donald Get Your Act Together,” it wouldn't work because The Big Apple Narcissus thinks it's better to be attacked in the limelight than to succeed out of it. Instead of taking the Post's advice, he'd have his secretary send the editors a nice note thanking him for the front-page placement.

Jonah Goldberg is a fellow at the American Enterprise Institute and a senior editor of National Review. His email is goldbergcolumn@gmail.com. Twitter: @JonahNRO.