It’s surprising how affecting a pair of shoes can be. Particularly when they’re empty, and when they’re one of 17 pairs representing the students and faculty killed at Marjory Stoneman Douglas High School in Parkland, Florida, on Valentine’s Day.

These empty shoes, bereft of those who normally wore them, were on the steps of my town’s high school as part of a student-led nationwide walkout to protest Congress’s failure to do anything to stop gun violence.

There have been 17 shootings on school grounds in the United States so far in 2018, 208 since Columbine. Including that initial 1999 rampage, which shocked the nation and defined the country today’s teenagers know, more than 200 have been killed. This does not count the additional 29 assailants who died, all but two of whom turned their guns on themselves. Far more have been injured and traumatized.

A dispassionate account of these incidents, most of which never rise to the level of national attention, makes for sobering reading. Most of the victims are young, but so are most of the attackers—too young to even be called gunmen (almost all are male). One six-year-old boy fatally shot his six-year-old classmate. So many of the incidents arise out of arguments, and have nothing to do with the usual false narratives of lone nuts, terrorists, and other bad guys. It’s easily accessible guns—not mental illness or monsters–that turn mundane hot-headedness deadly.

School shootings account for a tiny fraction of the 33,000+ (and rising) annual gun deaths in the United States, and schools remain among the safest places to be. Too many kids have more to fear in dangerous neighborhoods and volatile homes or, if they’re young men of color, from police. All mass shootings, including highly publicized tragedies in nightclubs, workplaces, churches, concerts, and Congressional ballgames and meet-and-greets, account for only two percent of firearm fatalities. Almost two-thirds of all gun deaths are suicides. Research by the Harvard School of Public Health and Everytown for Gun Safety consistently shows that guns in the home are far more likely to increase the risk of injury, especially but not exclusively when domestic abuse occurs. States that have more guns (and less restrictive gun laws) tend to have more gun injuries and deaths than states that don’t. Whether we’re talking about suicide, homicide, or accident, limiting access to guns saves lives,

When we widen the scope of gun violence beyond the school shootings that understandably horrify us, we see, if we care to, the grotesque number of casualties—38,658 gun deaths in 2016, the last year for which CDC data are available. That’s a lot of pairs of empty shoes.

But it is those kids in schools—the post-Columbine generation—whose grief and rage now galvanize a nation. They are not activists for arming teachers, turning schools into prisons, or rounding up the mentally ill. They want politicians to stop cowering before the NRA and commonsense gun safety regulations, and they won’t stop until they get them.

“We are only 24 percent of the population, but we are 100 percent of the future!” The girl leading the walkout I attended exclaimed through her tears.

Her fellow classmate urged everyone to vote. The students paid tribute to the lives that would never be lived, the contributions that will never be made by students just like them. Too many empty shoes. But the kids still here are stepping in and stepping up. It is our sacred duty to step, walk, march, run, speak out—and vote—alongside them.