The restart of fully in-person public school classes in less than a month will bring the return of nearly a million students — along with more than 4,000 school safety agents.

That’s reignited a raging debate over what role, if any, cops should have in classrooms, at a time when many children are especially vulnerable and anxious as the city slowly emerged from the COVID crisis.

Last summer, following mass protests against over-policing, Mayor Bill de Blasio promised to shift oversight of school safety agents from the NYPD to the Department of Education by June 2022 — a move opposed by the agents and decried by advocates who want them removed altogether.

Now, two years since the last “normal” first day of school, the argument over what keeps kids safe is being heated by physical-distancing and pandemic-related mental-health concerns, a historic reckoning on police brutality and a spike in shootings as the economy and social programs falter.

“We’re really concerned about the emphasis on return to ‘normal,’ because what was considered normal really wasn’t working well for a lot of kids,” said Johanna Miller, director of the New York Civil Liberties Union’s Educational Policy Center, which has long fought to remove police from schools.

“We’re really worried that there’s not enough energy spent on thinking about how to make the system safer, better, kinder for every kid,” said Miller.