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This week, America got another reminder of the fear that its schoolchildren must make sense of every day. On Tuesday afternoon, nine students were shot—one of them fatally—at STEM School Highlands Ranch, near Denver.

Though the two suspects are teenagers, STEM School Highlands Ranch is K–12, meaning that some young children were exposed to the violence. Among them was a second grader who told a New York Times reporter that he’d gone through lockdowns and active-shooter drills since kindergarten. That’s close to half his eight years of life.

His familiarity with potential crisis scenarios makes him part of an enormous group: In the 2017–2018 school year, more than 4.1 million students participated in a lockdown or lockdown drill, according to an analysis by The Washington Post.

These lockdowns can be scarring, causing some kids to cry and wet themselves. Others have written letters bidding their family goodbye or drafted wills that specify what to do with their belongings. And 57 percent of teens worry that a shooting will happen at their school, according to a Pew Research Center survey from last year. Though many children are no strangers to violence in their homes and communities, the pervasiveness of lockdowns and school-shooting drills in the U.S. has created a culture of fear that touches nearly every child across the country. In postwar America, have kids ever been so afraid and so regularly prompted to imagine their own suffering?

When I put that question to Paula Fass, a historian at UC Berkeley and the author of The End of American Childhood: A History of Parenting From Life on the Frontier to the Managed Child, she brought up two eras as analogues. The first was the early stages of the Cold War—the 1950s in particular—when fears of nuclear bombs had schoolchildren across the country doing duck-and-cover drills underneath their desk.

Surveys of children who grew up in this era indicate that 60 percent of them reported having had nightmares about atomic bombs. Fass herself lived through nuclear-prep drills, and while she said that they weren’t all that scary for her—they became rote, like reciting the Pledge of Allegiance—she recalled one night during the Cuban missile crisis, in 1962, as particularly anxiety-inducing for a high schooler: “I remember going out that evening on a date, and as we parted ways on the New York subway, we said to each other, ‘We may never see each other again.’”

The second period when families felt a looming threat, Fass said, was the 1980s and ’90s, when there was a “pervasive fear” of kidnapping among parents and kids alike. They received constant reminders of children who had disappeared—their faces were on TV, billboards, mailed flyers, and milk cartons. Some of the missing were from small towns, and others were from big cities. “It didn’t seem that there were any protected places,” Fass told me.

Fass, who wrote a book about child abductions called Kidnapped in 1997, said she heard of police officers showing up at schools in a push to record kids’ fingerprints, “not because they would be able to locate them that way, but because if they located their bodies, they’d be able to identify them.” All this scared children: A 1987 poll found that their most common fear was being kidnapped.

These widespread panics took a psychological toll—were they proportional to the actual risk? In the case of the Cold War, it’s hard to say, because while the United States never experienced a nuclear attack, there was a real sense that one might occur. (And some evidence indicates that ducking and covering might actually have been a wise tactic for these kids, at least compared with doing nothing at all.) The kidnapping panic, meanwhile, seems overblown in retrospect. In 1997, for instance, only about 100 of the 71 million children in America were abducted by strangers.

This isn’t to say that kidnappings and nuclear blasts wouldn’t be devastating—just that they are exceedingly unlikely. Shootings, too, seem to fall under this category of threat. Starting with Columbine, according to the Post, school shootings have claimed some 150 lives, including both children and adults. That’s 150 too many, but as a percentage of all the students and teachers who have been in a school in the past 20 years, it’s quite small. (The number of children estimated to have experienced gun violence at school during that period—roughly 230,000—is also much too high, but still a tiny minority of the tens of millions of American children in school at any given time.) Lockdown drills are schools’ attempt to protect kids from an unpredictable threat. But, across the country, children are being trained to anticipate an outcome that is both terrifying and extremely unlikely to happen to them.

While all of these threats—bombs, kidnappings, and shootings—are existential, what has changed over time is by what means people perceive the danger. In the 1950s, Fass said, television wasn’t yet pervasive—news typically came in 15-minute, once-a-night installments (and, of course, via radios and newspapers). “Certainly anyone who was awake knew about the Cold War, but they might not have been reminded of it in a daily way on television,” she noted.

The ’80s and ’90s were much different. By then, reports of missing children were omnipresent. “If you didn’t watch television,” Fass said, “I suppose it’s possible that you didn’t imagine this was going on. But if you had a TV, as 95 percent of all Americans did, it was impossible to escape from.”

A few decades later, news of school shootings is similarly inescapable. The latest tragedy is delivered not via milk carton but push notification. Parents and children in previous generations also feared for what might happen during the school day, but today, reminders of the danger come at an unprecedented volume and pace. When the news of another lockdown or another shooting could interrupt kids’ days at any moment, is it any wonder they’re so afraid?

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