In almost every New York City public school the first person greeting visitors is a uniformed New York City Police Department employee. Currently 93,000 public middle and high school children in this city cannot get to class without passing through metal detectors, having their bags searched, and receiving pat-downs.

To be sure, our schools do have problem with disorder. Ask most parents what they are unhappy with in their children’s school, and out-of-control classrooms will be near the top of their list.

In the vast majority of schools, though, the problem is not gangs and violence, but troublemakers and unruly kids. Seventy-seven percent of police personnel interventions in schools are non-criminal incidents. These discipline problems should not be confused with criminal problems. Flooding our schools with police is not the answer.

The real solution is to give more authority to teachers and principals, professionals who are invested both in the success of individual students, and also the success of their school.

The NYPD was put in charge of maintaining discipline in New York City schools in 1998, replacing the Department of Education’s authority over the School Safety Division. Since that time, the police have been responsible for a host of disciplinary procedures, both in and out of the classroom.

Principals, too, lack the tools to address chronic misbehavior. They cannot suspend students for more than five days without a hearing and approval by the District Superintendent. This burdensome bureaucracy means that misbehaving students continue to disrupt classes when a simple disciplinary measure could have solved the problem.

To build a culture of respect and discipline in the classroom, principals and teachers need good, old-fashioned authority — authority to send students to detention, to suspend them and even to expel them when necessary. They don’t need to call in the cops. Just check out the nearest Catholic school. Parochial schools do quite well at maintaining order without a police officer in sight.

The necessity for this police presence is not due to a rash of criminal activity, but due to cumbersome procedures that prevent teachers from meting out immediate discipline to disrespectful or disruptive students. Many teachers are inadequately trained for discipline, and many schools lack the space and the resources to give teachers the practical ability to remove students from the classroom when necessary.

The city could begin by ensuring there are enough resources to adequately staff and supply detention rooms. A state statute, the Safe Schools Against Violence in Education Act, was signed into law seven years ago. It mandates that each school have rooms for kids serving detention or in-school suspension. Due to financing issues, though, many schools have not been able to adhere to these regulations. The presence of police detracts from a school’s learning environment. Moreover, students get arrested for infractions as minor as saying a curse word in the hallway, and scribbling a word on a desk — perhaps a detention is merited in these cases, but certainly not an arrest.

These run-ins with the police are not only inconvenient, and often unjust and unnecessary, but also inefficient and time consuming. In fact, over 50% of students reported they were late at least once in the last month because of long lines waiting to pass through metal detectors.

Having police patrol schools is not just a mismatch with the real discipline problem, but it is actually harmful to education. Their presence alone sets exactly the wrong tone for a school. Subtly, and not so subtly, it makes children, parents, and even teachers see schools as jails, not as places of excitement and opportunity. Our current approach to school discipline is both too lenient and too harsh. Schools need to implement specifically delineated policies on discipline and to toughen the day-to-day authority of teachers and principals. Then teachers can get back to the business of teaching and police officers can get back out on patrol and make arrest for real crimes.

Mr. Yassky is a City Council Member.