The first thing I thought about when I saw the news of the latest school shooting, which left four teenagers dead in Michigan, was my younger kid. He is joyful and thoughtful, and he worries. This child was excited to go to middle school because: It has metal detectors!

In his beautiful mind, metal detectors = a promise that he won’t die if another child wants to pull out a semiautomatic weapon that his dad allegedly bought at a store nearby, maybe during a Black Friday gun sale.

How would I explain away this one, like I had tried before? How could I help him feel like his mother was doing her job — protecting him — when I knew I couldn’t, really?

Some might point out that it’s a very small population of kids who have been privy to the particular horror of school shootings. Well, sort of. This week, four (so far) children out of 7 million in this nation are dead, and a handful are grievously injured. But the ripples go far and wide. Our kids are traumatized. We parents are traumatized. People without kids are traumatized.

The prosecutor in the Michigan shooting acknowledged the wide-ranging impact with the charges against the 15-year-old suspect: Not only was he charged with murder, assault and weapons charges, he was also charged with terrorism. Because that is the definition of what was done. A shooter terrorized not just the children killed, but the thousands of others who can’t sleep tonight.

When my child looks at me and says he wants to go to a school with a metal detector, he is saying what I already know: It could happen here.

School shootings, however statistically rare, cast a long shadow. They have created an incredible amount of trickle-down trauma among our kids and their caretakers. Schools have installed metal detectors, hired armed guards and created new (to this generation) macabre drills.

Our kids have been playing “shooter drill” since they were babies, and the result is just more trauma.

A white paper, published last year by Everytown for Gun Safety, the American Federation of Teachers and the National Education Association, showed mounting anecdotal evidence that the shooter drills are inflicting trauma on kids and leaving them anxious and unable to focus on school.

Drills vary from school to school, but some include actors who are masked gunmen. At Lake Brantley High School in Altamonte Springs, Fla., students were not told that a “code red” drill was a drill. According to the paper, one student said, “No one really talked about the emotional impact, which I feel like is more longer lasting. I feel like [administrators] never really recognized that people had panic attacks.”

In another instance, noted in the paper, there was a poster hanging in a kindergarten class, to be sung to the tune of “Twinkle, Twinkle, Little Star”:

Lockdown, Lockdown. Lock the door.

Shut the lights off, Say no more.

Go behind the desk and hide.

Wait until it’s safe inside.

Lockdown, Lockdown, it’s all done.

Now it’s time to have some fun!

My child was told during a drill in first grade that they were hiding from a panda that had escaped from a zoo. Yet he somehow knew that it was something much more nefarious that he was preparing for, and it impacted him deeply.

It’s unclear how helpful these drills are, though some this week have said they saved lives at Oxford High School in Michigan.

Drills or not, our kids take notice, maybe before we ever want them to. When the Sandy Hook babies were murdered, my older child, the same age as the 6- and 7-year-olds killed, noticed his school’s flag “wasn’t all the way to the top,” and he asked me why, every day. How, I wondered, how did he notice this? How will I ever explain?

I can’t explain away the lives and deaths of four teenagers, and how maybe they argued with their mom that morning because they had spent too much time on TikTok. Or hugged their dad just because. Their shampoo is still on the edge of the tub. Their bed is unmade.

And now they just … aren’t.

I think about all the times I tried to protect this child of mine from the dark knowledge that kids with guns kill kids. I’d like to tell him it wouldn’t happen at his church or in a prayer group. That this couldn’t happen at his school, his movie theater, his concert. I’d like to believe what so many believe: It’s such a small number, it can’t happen here.

But it happened at a synagogue near my hometown. A close high school friend lives in Parkland with her sons, one of whom was just a year shy of sitting in that high school during that particular massacre.

It’s far away, and a minute possibility. Except it isn’t. It’s always right here.

And today’s teenagers know it. A majority of teenagers said they feared a school shooting could happen at their school in a 2018 survey by Pew Research, conducted after the Marjory Stoneman Douglas High School shooting that left 17 dead. Other research has showed a massive increase in antidepressant use among youths who were exposed to local school shootings.

“It’s important to recognize that there are many other students who aren’t directly hurt, but they nevertheless experience these large costs that follow them in to adulthood,” said Maya Rosin-Slater, lead author of the antidepressant study and associate professor at Stanford. “These events not only shake up communities and generate deaths and injuries and all the tragedy that comes with that, but they also have these long-term consequences.”

I’m not scared of guns, per se. My boys know how to shoot (they don’t like it). We had the first day of deer season off from school where I grew up. My grandfather, a hunter who kept his guns carefully locked away, had a jolly sign on his door that read: “This house is protected by a shotgun three nights a week. YOU guess which three.”

Yet the specter of guns and the horror they inflict always lurked in the background. The potential evil of them became clear to me, starting with the day my brother’s friend, a sweet boy who shared the back of our station wagon when we saw “Ghostbusters” at a drive-in, fatally shot himself before he could even drive. A few years later, a friend’s brother who I had known since I was 4, did the same.

Those childhood nightmares haunt me today, yet they feel small compared to the collective nightmare our kids are living through now, when they can rattle off places like Parkland and Sandy Hook and Columbine as easily as state capitals.

My son has already heard about this recent shooting. He will surely hear about it from his friends this week. Friends whose lunches are taken by the supposed bully, who I suspect is lonely and sad. Friends who have gotten into fights because someone cut in line. Friends who are big but have innocent hearts. Friends who, in generations past, would have fought the bully, told on the line cutter, punched back without fear that someone would shoot them the next day.

But now that fear is there, every day.

“It’s okay. I’m not as scared as I used to be,” my son said to me last night, when I caught him looking over my shoulder as I read a story about the shooting. “I feel better, because our metal detectors are working again.”