A guy just won the Republican nomination for president by spending no money, hiring no pollsters, running virtually no TV ads, and just saying what he truly believed no matter how many times people told him he couldn’t say that.

I always hoped I’d see this once before I died. Pay attention, because it’s the last time we’re going to see it.

For those of you not yet on the Trump Train, I know you don’t want to vote for Hillary, but all the pundits have been trying to convince you that Trump’s a complete fraud. (At least after moving off of their smug assurances that he wouldn’t make it out of Iowa.)

When Trump launched his campaign by talking about Mexican rapists and the wall, his critics hysterically denounced him, rushing to TV to say he did NOT represent the Republican Party! Only after it became resoundingly clear that large majorities of Americans agreed with Trump did his critics try a new tack: He doesn’t even believe it!

That’s what my friend Andy McCarthy at the now defunct National Review wrote recently. I had to spend the weekend figuring out how to attack a friend without saying, “This is the most retarded argument I’ve ever heard.”

Here goes: This was not Andy’s best effort.

Of all the arguments that could be made against Trump, McCarthy settled on: Don’t trust him on immigration!

McCarthy bases this claim on a stray remark Trump made as a businessman four years ago in which he regurgitated the official GOP line about Romney — and which was being parroted 1 million times a day on Fox News, not to mention CNN and MSNBC.

To wit, Trump told Newsmax that Mitt Romney “had a crazy policy of self deportation which was maniacal,” adding, “he lost all of the Latino vote … he lost everybody who is inspired to come into this country.”

It is strange that Trump would denounce “self-deportation,” which is like a chocolate sundae compared to his own plans for illegals.

But to give you the tenor of the interview, Trump went on to promote “Celebrity Apprentice,” note that he had just bought the Old Post Office building in Washington, DC, and boast about his recently-acquired Ritz-Carlton Golf Club and Spa in Jupiter, Fla. — “which is a phenomenal area.”

Also, a lot of people didn’t like the phrase, “self-deportation.” Why not just say: “They’ll go home the same way they came”?

So is Trump lying about his signature issue, immigration?

The countervailing evidence to that 2012 pop-off is:

— Nine months of Trump soaring to the top of the polls and slaying all comers by talking about how he’s going to build a wall and make Mexico pay for it;

— His never, ever, ever backing down on the wall, sanctuary cities, anchor babies, suspending Muslim immigration, etc, etc. despite unprecedented attacks from both the liberal and “conservative” media;

— The fact that he talks about deporting illegals and building a wall at every single one of his massive rallies and always gets the biggest, most sustained standing ovations when he mentions the wall;

— The blizzard of Tweets he sent out in 2013 denouncing Rubio’s amnesty bill as it was sailing through the Senate, supported by not only the entire liberal media, but Rupert Murdoch, Fox News, most of talk radio, and every other GOP candidate for president this year, including, for a while, Ted Cruz — whose job was to know about senate bills, unlike a Manhattan real estate developer;

— Trump’s one and only policy guy is the magnificent Stephen Miller, who was Sen. Jeff Sessions’ main immigration guy.

And so on.

Maybe Trump is the Manchurian Candidate and contrary to his decades of concern for the American working class, he really just wants fancy people in Manhattan to like him.

Maybe the window into his soul is what he said in a promotional interview four years ago about Romney’s phrase “self-deportation.”

Maybe 50 years of Trump’s talking about the working class, regular Americans was all a clever ruse leading to this one shining moment when he would trick Americans into voting for him, so he could sell us out, like all the other candidates would have.

On the other hand, maybe he’s simply changed his mind about that 2012 remark.

I’m bitter and cynical enough on immigration that I don’t trust anyone not to betray us. But if there was ever a candidate we could believe will build a wall and stop the mass importation of the Third World, it’s Trump.