Border wall, San Ysidro, CA

Source: Bigstock

If you were elected president after decades of politicians doing nothing about the millions of illegals pouring into our country every year, committing crimes, dealing drugs, driving drunk, molesting children and killing Americans like Kate Steinle, and your central campaign promise — repeated every day — was to build a wall, wouldn’t you have spent the entirety of your transition period working on getting it done?

Wouldn’t you have been building prototypes, developing relationships with key congressional allies and talking to military leaders about using the Seabees or the Army Corps of Engineers to build the wall?

Wouldn’t you skip the inauguration and take the oath of office in San Diego so you could get started on supervising wall construction immediately after putting your hand on the Bible and being sworn in as the leader of the free world?

You would if you meant it.

Well, Donald Trump didn’t do that.

OK, sure he could have taken the oath in D.C., gone to a few balls, then started the wall on day two of his presidency. But he didn’t do that either.

Maybe I’m a literalist. A zealot. When people kept telling me to be patient — the wall is coming! — I nursed a private hope that I was wrong, and they were right.

It is now crystal clear that one of two things is true: Either Trump never intended to build the wall and was scamming voters all along, or he has no idea how to get it done and zero interest in finding out.

He sacrifices every opportunity to make the wall happen.

For two years, Trump pretended to believe the president of the United States needs express authorization from Congress to defend the nation’s borders and blamed the Republican majority for not “funding” the wall.

In a few weeks, he’ll start blaming the Democratic House.

Last week — several whole days ago — Trump said over and over again that he would shut down the government if he didn’t get funding for the wall — the precise thing he claims he needs. “We need border security. The wall is a part of border security,” he said. “If we don’t have border security, we’ll shut down the government.”

Trump wore the shutdown over the wall as a badge of honor: “You want to know something? OK, you want to put that on me. I’ll take it. You know what I’ll say? Yes, if we don’t get what we want … I will shut down the government. Absolutely.”

One week later, The Drudge Report:

WALL FUNDING OFF TABLE

In other words, Trump is doing exactly what I feared he would do in the worst conceivable way. He’s not building the wall, while making ridiculous promises right up until the second before he folds.

The Washington Post loves to find the one crazy, trailer park lady who supports Trump because she’s had religious ecstasies about him, but most people who voted for him did so with a boatload of qualms.

The basic factory setting on the perception of Trump is: gigantic douchebag. This is a man who manufactured fake Time magazine covers featuring himself with the headline, “Donald Trump: The ‘Apprentice’ is a television smash!” so that he could put framed copies of it on the walls of his clubs.

His business is convincing people with lowbrow taste to give him their money.

He’s a vulgar publicity hound who used to call reporters in a fake voice and pretend to be his own PR agent, “John Miller” or “John Barron,” so he could brag that actresses wanted to date him.

On one “Apprentice” episode, the reward for the winning team was: to see Trump’s apartment. Not to eat there or spend the night. They got to see it. “As a little treat,” he said, “you’re gonna see the nicest apartment in New York City.” He added: “I show this apartment to very few people. Presidents, kings …”

It’s not as if a majority of his voters weren’t clear-eyed about what kind of man he is. If anything, Trump’s vulgar narcissism made his vow to build a wall more believable. Respectable politicians had made similar promises over the years — and they always betrayed the voters. Maybe it took a sociopath to ignore elite opinion and keep his word.

On the basis of his self-interest alone, he must know that if he doesn’t build the wall, he has zero chance of being re-elected and a 100 percent chance of being utterly humiliated.

But when Trump is alone with Ivanka, they seem to agree that the wall has nothing to do with it. The people just love him for who he is! In a country of 320 million people, I’m sure there are some, but I have yet to meet a person who said, Yeah, I don’t really care about immigration or trade, I just love his personality!

What else were we going to do? He was the only one talking sense. Unfortunately, that’s all he does: talk. He’s not interested in doing anything that would require the tiniest bit of effort.

In the end, we’ll probably find out “wall” was Trump’s “safe word” with Stormy Daniels. It’s just something he blurts out whenever he’s in trouble.

He’s in trouble now. As absurd as the Russia nonsense is, the details about Trump’s sleazy associates, the porn star, the Playboy playmate and his seedy business practices leave his supporters feeling queasy, even if he hasn’t committed any crimes.

Instead of joining a fight that will make his most ardent supporters cringe no matter how it comes out, why not choose a battleground where he’s guaranteed a win? If Trump used the military to build the wall — actually build it, not keep telling us he’s going to build it — the Democrats will go mad.

They’ll hold impeachment hearings, file a million lawsuits, produce weeping children reading from phony scripts written by immigrant rights groups — and Trump will win. The public will support Trump overwhelmingly, and the left will be forced to keep reminding voters why they hate Democrats.

Instead, what he’s doing now absolutely guarantees that the next president will be a Democrat and, given today’s Democratic Party, that president will be Kamala Harris.