From the series, "The Location of Justice: Systems", Urban Omnibus

In the past — or in schools with higher proportions of white students — a student acting out might garner an intervention by their principal, or a concerned teacher’s phone call to parents. But today, throughout the US, discipline in many schools has become a matter of law enforcement, rather than education. In New York, the majority of school guards — 5,000 School Safety Agents patrolling 2,300 public and private schools — are civilians employed by the School Safety Division of the NYPD; though unarmed, they can issue summonses and arrest and handcuff students. There are also roughly 200 armed, uniformed NYPD officers who are permanently stationed in schools and report to local precincts. But even in schools without permanently assigned cops, police officers working for local precincts may be summoned into the school at any point. For them, the school building is just another part of the beat.

In the 1990s, national anxiety about drugs and shootings in (mostly suburban) schools combined with cities’ growing emphasis on “order maintenance” policing to create a “zero tolerance” standard for school discipline. Federal funding hung in the balance, so states including New York agreed to adopt the standard, under which small infractions could bring law enforcement into schools. The NYPD absorbed the School Safety Division,