Ted Cruz did the right and honorable thing by suspending his presidential campaign Tuesday night. John Kasich should follow suit. It’s time for the party to unite against Hillary Clinton.

Donald Trump’s massive win Tuesday in Indiana confirmed the trends of the last two weeks: A majority of GOP voters have decided he’s their nominee.

For any other candidate to keep fighting would only help Hillary.

There’s no misreading this electorate: In three straight weeks of voting, Trump solidly outperformed his pre-election polls.

You could understand his foes writing off his 60 percent landslide in New York to home-state advantage. But then he scored 54 percent to 64 percent in the five “Acela primary” states the next

week — and next won Indiana with over half the vote.

And where turnout had dipped in the Acela states, Hoosiers hit the polls in droves. Trump didn’t win because GOP voters have given up — but because they’ve made up their minds.

Back when the race held a dozen candidates, anti-Trumpers kept talking about his “ceiling,” insisting that someone would beat him once the field cleared out. Reality has proved the opposite.

Even before Cruz pulled out, Trump was on track to win Nebraska’s winner-take-all primary next week and most of the remaining contests — all the way to yuge victories in California and New

Jersey on June 7, blowing through the 1,237-delegate line.

Indiana turned all those contested-convention plans into scrap paper.

The Republican electorate has decided: It’s time to focus on keeping Hillary Clinton out of the White House.

November’s election is the most important in at least a generation. As president, Hillary Clinton would get to shift the Supreme Court decisively left, starting with the Scalia seat — freeing her to pursue President Obama’s extra-constitutional “executive order” strategy to rewrite the nation’s laws, even if Republicans somehow hold Congress.

ObamaCare will grow bigger and more oppressive, with ever less choice for patients and doctors alike. The rest of the “administrative state” will blossom, too: US immigration policy will focus on recruiting Democratic voters — while the IRS becomes Democrats’ enforcement arm.

With the whims of the cultural elite increasingly given the force of law, social engineering will run amok: Political correctness will move from ruling the campus to the workplace and soon enough the media.

Crony capitalism — which has already seen the “too big to fail” banks get even bigger under Obama — will become the only capitalism. (Want to grow? Invest in lobbyists — and give to the Clinton Foundation.)

That guarantees more economic stagnation — with good, honest jobs ever more scarce.

And a sagging economy will force ever-greater cuts to an already-overstretched military. Even if Clinton is secretly as tough on foreign policy as some claim, she’ll lack the might to do right.

Oh, and both Ted Cruz’s Constitution-centered conservativism and John Kasich’s problem-solving pragmatism will be dead letters in American politics.

Only Donald Trump and a united Republican Party can stop it, by triumphing on Election Day.

It won’t be easy: Clinton will raise a billion dollars for a “fear and smear” campaign aided by the big-data expertise that helped Obama smash Mitt Romney.

Trump has his work cut out for him, convincing regular Republicans to show up and vote for him along with the millions of new voters he’s rallied to his cause.

Ted Cruz rightly realized that the best thing he could do for America right now was to get out of the way and let Trump start fighting the real enemy.