Soon after Trump’s announcement speech, I said he would win the nomination and likely the election.

Soon after Trump’s announcement speech, I said he would win the nomination and likely the election. It wasn’t that hard to predict. For anyone familiar with the Republican Party’s repeated betrayals of the American people, it was a 2-foot putt.

I issue this warning with the same certitude — in fact, for the exact same reason I knew anyone running on Trump’s platform would have unbreakable support from millions of voters.

What coalesced Trump’s base, what made his support tempered steel, was the fact that voters had been lied to, over and over again — on many things, but most smugly and repeatedly on immigration.

How many times did we have to see the GOP choke? There’s 30 seconds left in the game, Republicans are down by two, they move the ball up the court, have a man in position — and, every time, the GOP would do anything to avoid taking the 3-point shot.

That is the beating heart of the anger that voters felt toward the party. No one trusted Republicans to ever score when they had the ball.

It’s why Trump’s supporters stuck with him through thick and thin — his attack on war hero John McCain (he deserved it), his mocking a disabled reporter (a lie), his lazy first debate performance (totally true) and the “Access Hollywood” tape (oh well).

After he gave that Mexican rapists speech, and never backed down, Trump’s base would have brushed off six more “Access Hollywood” tapes. All because they think Trump will take the shot.

He’d better! As the popular vote proves, we don’t have 30 seconds on the clock. It’s only three.

But if he breaks a major campaign promise, his supporters will turn on him with a blind ferocity, dwarfing their rage toward Jeb! because Trump’s is the more exquisite con. He will have duped them. And he will never, ever, ever get them back.

Most of his promises can be kept with little trouble: He will appoint good judges, cut regulations, replace Obamacare and renegotiate trade deals. In other words, he’ll do all the things any Republican president would do — plus the trade deals.

But the moment Trump attempts to make good on his central promise — to remove troublesome immigrants and give us our country back — every major institution in America will declare war on him.

Trump knows that. In his Phoenix immigration speech, he said: “To all the politicians, donors and special interests, hear these words from me and all of you today. There is only one core issue in the immigration debate, and that issue is the well-being of the American people.”

If powerful interests were not furiously opposed to Trump’s idea that immigration should benefit Americans, rather than foreigners, our immigration policies would already do so.

It will surprise consumers of American media to learn this, but every promise Trump made on immigration is already the law. Why? Because politicians know that’s what the public wants. So they pass the laws — and then refuse to enforce them.

But if Trump doesn’t appoint the sort of people capable of fulfilling his campaign promises on immigration, he will fail. He’ll be just another lying politician, and his supporters will watch in horror as rapists, terrorists and drug dealers continue living in our country.

There will be no one person to blame. No one is ever to blame in Washington. They just won’t get it done.

Then, well into the Trump presidency, some Muslim will commit a machete attack, shoot up a community center, stage a mass slaughter at a gay nightclub or bomb a marathon. There’s no question but that the terrorist attacks won’t stop — unless Trump nominates people who know what needs to be done and aren’t intimidated by testy New York Times editorials.

There will be more Americans like Kate Steinle, Grant Ronnebeck and Joshua Wilkerson killed by illegal aliens. There will be more children addicted to heroin brought in by Mexican drug cartels. There will be more parents joining the Remembrance Project.

But this time, they’ll blame Trump.

And then it will be Trump’s opponents saying, “What is wrong with our politicians, our leaders — if we can call them that. What the hell are we doing?”

If Trump betrays voters on immigration, he can have as many rallies as he wants, but Americans will say, Been there, done that — you screwed us. He will never escape the stink of broken campaign promises.

So unless Trump has another 60 million voters hiding someplace, the appointments he makes today — to State, Defense, Homeland Security, Labor, even the IRS — will determine whether he is remembered as America’s greatest president, or if the Trump name becomes a cautionary tale in American politics.

At this precise moment — not after his inauguration, not in year two of his administration, but today, as he fills his Cabinet — Trump has to decide if he’s going to be like every other Republican and throw a brick or grab the ball and score.

Whether he’s listening or not, his supporters are screaming: TRUMP! NOW! TAKE THE SHOT!!!