This Feb. 21, 2018 photo made available by Lex18 News, shows a group protesting school safety in Laurel County, KY. In the wake of a mass shooting at a Florida high school, parents and educators are mobilizing to demand more school safety measures, including armed officers, security cameras, door locks, etc. (Claire Crouch/Lex18News via AP)
This Feb. 21, 2018 photo made available by Lex18 News, shows a group protesting school safety in Laurel County, KY. In the wake of a mass shooting at a Florida high school, parents and educators are mobilizing to demand more school safety measures, including armed officers, security cameras, door locks, etc. (Claire Crouch/Lex18News via AP) Credit: Claire Crouch

Before the blood dried in the hallways and classrooms of Marjory Stoneman Douglas High School, Donald Trump blamed the massacre on poor security and urged the arming of America’s teaching force.

As the head of a school for 19 years, I’ve tried not to imagine that kind of tragedy. But one can’t be immune from or indifferent to the possibility that children in your care might be mowed down by a madman with a rapid-fire weapon.

When I read about Columbine, my heart ached. When I saw reports about Sandy Hook it burst. To a teacher or any member of a school community, these images are never far from the mind’s eye — small bodies covered with sheets, parents, caregivers and teachers frozen in unimaginable grief.

The response to arming teachers has been unambiguous. While a few anecdotes report teachers who are already packing heat, or are more than willing to carry, most teachers and administrators are outraged. Teachers didn’t join the profession in order to double as armed guards. The arguments against arming teachers are obvious and too numerous to fully explicate.

Trained police officers have an 18 percent success rate of hitting an armed target in a gunfight. The possibility of a teacher successfully using a pistol to stop a man armed with an assault rifle is between negligible and zero. Many assailants have worn body armor. When I was trained as an infantry soldier, neither my platoon-mates nor I could dependably hit a silhouette at 20 paces with a .45-caliber handgun — even with total calm and a stationary target.

Mishaps would be exponentially more likely than heroism.

No plausible scenario makes a gun readily available to a teacher and also keeps it secure from intentional or accidental mischief. It’s just irrational.

The psychological impact on children who know adults are armed is incalculable. While school shootings are real, and horrifying, the odds against a shooting in a particular school are astronomical. Why create emotional trauma through aggressive policies that are designed for the rarest exception?

For all these reasons, I would not allow my child to go to a school with armed teachers or administrators.

All of these arguments have been made and will, heaven help us, prevail. But one glaring reality has not entered the dialogue: Armed teachers and security guards cannot not keep our children safe, even if trained like Navy SEALS with expert marksmanship and unshakable confidence.

In my school in Manhattan, safety and security were constantly debated. At one point, after Sandy Hook, a few board members proposed armed guards. I had many objections, but one argument made the difference. What, I asked, makes you think a disturbed person with an assault weapon will try to penetrate the school?

Hundreds of students gather in groups outside before and after school. Our lower and middle school students travel to Riverside or Central Park in groups of 15 or 20, nearly every school day. A major part of our curriculum uses the city and its incredible resources. We take subways, buses and walk to nearby museums. Shall we just keep everyone inside and convert a vibrant school into an armed citadel?

None of this was intended then, or now, to take safety or security lightly. We had lockdown protocols, evacuation procedures, high-tech security cameras and careful control over who entered the building. But the arming of anyone went drastically beyond diminishing returns, to the point where the psychological damage and risk of mistake vastly outweighed any potential for added safety. Guns are simply too dangerous, whoever the bearer.

There are only two things that can prevent the mass murders that have become America’s shameful hallmark in the world.

Boys like Nikolas Cruz were not born evil or mentally ill. Seething anger that erupts in a spasm of blood is not a genetic or theological condition. It is often a product of neglect and abuse, bullying and humiliation. Every backstory of a man bent on extreme violence is a story of a boy bent by the indifference or cruelty of a milieu lacking love and compassion. It may happen at home or it may happen in a school where some boys are isolated in plain sight or taunted with no one paying attention. The one nearly universal factor is that these boys are desperately lonely. We must address that.

And, like an addict hoping for recovery, we must admit that our country loves its guns more than it loves its children. We must address that too.

All politicians or policymakers who kneel before the NRA, cite the Second Amendment or press ludicrous proposals like arming teachers have been complicit in the slaughter of innocent children. And they will be complicit in the next. And the next.

Steve Nelson lives in Boulder, Colo., and Sharon. He can be reached at stevehutnelson@ gmail.com.