#DOE’s rogue canceling of Columbus Day shows de Blasio isn’t in control

Mayor Bill de Blasio doubled down Thursday on his claim that he and Schools Chancellor Meisha Ross Porter were blindsided by the city Department of Education’s move to replace Columbus Day with Indigenous Peoples’ Day. If so (and that’s all too possible), then it flags how neither one of them truly controls the city’s public-school system.

And the mayor’s gambit of blaming ex-Chancellor Richard Carranza doesn’t change a thing: Even if Carranza started plans for the change, no functional system would keep Porter and de Blasio in the dark on so explosive an issue.

Clearly, the top ranks at DOE don’t care because the mayor and his chancellor are lame ducks: New leaders will take over in January. But will even they truly have control?

In reality, the bureaucracy answers more to a force that never gets replaced: the United Federation of Teachers, with all its power to “gum up the system” (as its president, Mike Mulgrew, once put it) and all its sway with the City Council and state Legislature.

Heck, all signs are that de Blasio wanted the public schools open sooner and wider than has yet to happen — but Mulgrew thought otherwise, and that’s what mattered.

De Blasio is the mayor. He has mayoral control over the schools and is the boss of the bureaucracy. When is he going to act like it?