Not everyone in the Mamdani administration is deluded: Schools Chancellor Kamar Samuels just told the ugly truth about two sacred cows of the local education establishment — the state-imposed class-size mandate and the lunatic “hold harmless” policy.

Testifying Monday before the City Council Education Committee, Samuels warned that it’ll be “very difficult” for the city to meet the mandate of no more than 20-25 students per class, depending on grade level.

Compliance now stands at 64%, he says, but the city won’t even hit the 80% mark by September. 

It’s not just the cash needed; the city has to find more classrooms and hire more teachers; both take time.

State Sen. John Liu has teased his openness to granting more time, and even some state aid, so the city can reach 100% compliance by fall 2027.

Liu and others had blamed the last mayor, but even in the Mamdani era the city Department of Education finds itself unable to move fast despite fast-declining enrollment.

Now that the temporary “bump” from the influx of migrant kids has passed, the DOE is responsible for just 844,400 students, a huge drop from the 1.1 million as recently as 2012.

The chancellor’s other surprise was dropping shade on the “hold harmless” policy, which insists on giving every single school at least as much funding as the year before, even when its enrollment keeps plummeting.

All of this risks the rage of the United Federation of Teachers, which got the Legislature and gov to impose the class-size mandate to ensure its active ranks would grown even as enrollment shrinks — and which burns in fury at any talk of cutting even blatantly wasteful school spending.

Perhaps Mayor Zohran Mamdani realizes he doesn’t need the UFT’s love — especially when he faces multibillion-dollar deficits and when a full 29% of the city’s budget, an obscene $39 billion, goes to a school system where enrollment is down, truancy is up and achievement is stagnant.

Mamdani’s schools chief has the opportunity to align budget priorities, per-pupil spending and academic performance across all public schools.

Maybe, just maybe, sane voices at City Hall are whispering that finding basic efficiencies at DOE (and getting Albany to relax the UFT’s mandate) are a practical way out of the budget mess.

Or the mayor doesn’t dare cross the union, and Samuels is truth-telling his way out of his job.