A new poll show Bernie Sanders with a sizable lead over all his rivals for the Democratic nomination, and moderate liberals are beginning to wonder whether their party has a death wish. President Trump would like nothing better than to campaign against a self-proclaimed socialist who’d destroy our economy, hollow out our military and open our borders wide.

Trump seems likely to defeat anyone the Dems put up, but against Sanders it might be a blowout. I like Trump, so maybe I should gloat. Only I don’t.

Taking the long view, Sanders’ popularity should be a cause for concern. According to a recent Quinnipiac poll, 53 percent of Democratic voters under 35 back Sanders, and support for socialism is especially strong among the young. When polled, most Americans say they wouldn’t vote for a socialist, but more than a third between 18 and 34 say they would.

They’re Millennials and post-millennial Zoomers, and as we age as a society they’re going to become a larger bloc of voters. Leftists are gleeful about this. “The future belongs to us,” they think.

Maybe not. Psychologists tell us that we tend to become more conservative as we age, and that’ll happen to the Zoomers, too.

As George W. Bush said, “when I was young and foolish, I was young and foolish.” So when the Zoomers have more at stake in the country, when they marry and have kids, they’ll be less ready to tear everything down.

But that’s just the problem. Zoomers have weaker prospects and less of a stake in the country than past generations did. Why? Terrible schools and massive educational loans.

Boomers went to K-12 schools that were among the best in the world. Some went to colleges where we got a fine education that didn’t cost an arm and a leg. Our degrees suited us for work, and we took our place in an economy that offered jobs.

Today? K-12 schools have become mediocre, and high-school kids go off colleges to be trained in basic skills — except that doesn’t always happen. Instead, they’re trained to be unemployable, with courses on, say, victimhood, and sent out to the workforce with the message that employers are evil and they should rage against the machine.

Thanks to the booming Trump economy, there are jobs for them, though perhaps not jobs for those trained in grievance studies. Even then, they’ll find it a struggle to pay off their massive educational loans.

That’s made Zoomers postpone, in some cases forever, the milestones to give people a stake in their country — homes, marriages, children.

Student debt exceeds $1.6 trillion. Half of the more than 40 million student borrowers don’t pay down the principal, and millions find themselves becoming debt slaves. They’ll never be able to pay off their loans, and when that happens, you just give up.

Sanders promises to wipe out student-debt loads. No wonder he’s popular with the Millennials and Zoomers.

His popularity with the young is the sign of an unfinished Trump revolution. It’s easy to point to a number of things Trump ran on in 2016 that didn’t happen. The educational mess is just one of them.

There’s also the tax loopholes that didn’t get fixed, campaign laws that didn’t get mended, health-care reforms that never happened.

Sure, cut the guy some slack. Not everything gets fixed at once, not even in three years. But a good start might be to recognize what’s left undone, and to fix what’s easily fixable. It wouldn’t take great political will to offer debt relief for educational loans.

Or how about, as a cure for future student loans: no government-backed lending if tuition exceeds $30,000 a year. Forget Oberlin, unless Daddy wants to pay. Go to State U instead. You’ll get a better education as well.

In 2016 Trump asked us to remember the unemployed blue-collar worker in the heartland. Today there are millions of young people who’ve been robbed of their future by their educational loans. Let’s remember them too.

F.H. Buckley is a professor at Scalia Law School and the author of American Secession: The Looming Threat of a National Breakup.