It has been forever since kids were required to learn anything important to obtain a high school diploma in New York City — but who knew that they didn’t even need to go to class?

But as this newspaper’s tireless Susan Edelman reported over the weekend, NYC Department of Education rules hold that kids can’t be barred from graduating “for lack of seat time.”

In case you are wondering, “lack of seat time” is a euphemism for “never comes to class,” plain language rarely being spoken at the DOE.

Edelman reports that, according to the rules, students must “meet class standards” to earn graduation credits, never mind that “standards” in city schools are notoriously undemanding. And when an actual classroom presence is not among them, you get the idea.

In practice, kids who miss weeks, sometimes months, of classes can sashay in at the last minute, do some perfunctory makeup work and then they are good to go for graduation.

Where they go from there is an open question. Some might go to Harvard or other elite colleges and universities, of course, but damned few do. Most go on to sad lives — functionally illiterate, innumerate and pretty much incapable of meaningful participation in the modern economy.

So there is a word for the seat-time sham: fraud, pure and simple.

Among the victims are the kids who come to class and do the work, in the end being presented with shamefully degraded diplomas; the few remaining potential employers or college admissions officers who think the documents have value; and even the truants themselves. Most of those were willing participants in the double-dealing, of course, but doubtless many harbor high expectations anyway. Soon they will learn better.

The process began two decades ago, when the state Board of Regents began to degrade its gold-standard graduation requirements, the subject-specific Regents exams. (Those tests are about to be jettisoned altogether, as Albany continues to shirk its own duty to educate New York’s children.)

The point was to mask the fact that the state’s schools, particularly its urban schools, were increasingly unable to meet exacting standards. So, with the Regents leading the way, school districts everywhere began to cut performance corners.

In New York City, the process quickly produced thousands of youngsters who held diplomas but who couldn’t do even basic college-level work.

More or less in self-defense, the City University of New York — which receives the bulk of its undergraduates from city high schools — instituted rigorous remediation programs intended to keep unprepared students out of its senior colleges until they could perform to senior college standards.

This, unhappily for the deceivers, gave the game away. The standards activists at StudentsFirstNY ­began comparing the graduation rates of individual high schools with CUNY’s remediation enrollments — and discovered that a distressing number of high schools with high graduation rates also had disproportionately high numbers of grads in remediation.

The obvious culprit was degraded performance benchmarks, which produced high numbers of unprepared graduates. But rather than address the actual problem, attention was turned to CUNY’s ­remediation program.

The university began lowering its own standards, while pulling the shades on what once was a crystal-clear process. Now it is extraordinarily difficult to make the sort of comparisons StudentsFirstNY made to such clarifying effect — and few really believe that the program retains much value.

Today, the deceptions continue.

Rather than address the social, cultural and behavioral issues that contribute so heavily to public school underperformance, New York’s educational establishment increasingly blames bigotry.

New York City Schools Chancellor Richard Carranza may be the most egregious offender, with his implicit-bias obsessions and the enduring allegations of racially motivated hirings and firings. But he isn’t the only one. Certainly Mayor Bill de Blasio is complicit.

It’s a topic worthy of examination and discussion, of course. But one aspect of the controversy seems pretty much ­beyond dispute: When people are arguing about “implicit bias,” they aren’t talking about administrative incompetence, ­diminished standards, the shipwreck that passes for public education in so many of the state’s cities — or “seat time.”

So score one more for the obscurantists.

Twitter: @RLMac2