Somehow, Emma González found the strength to be silent. At a March 24 rally in Washington, D.C.—in front of a crowd larger than any other that had assembled in the nation’s capital—the 18-year-old Floridian spoke passionately about the loss of 17 students and teachers at Marjory Stoneman Douglas High School, friends who would never joke or wave or hang out after school again. Cara Loughran would never. Chris Hixon would never. Luke Hoyer would never, she intoned, releasing each name into the air, one by one.

Then the young woman, who in just weeks had become the face of a national movement, offered the only response the dead could make: silence. As the crowd called out her name, as they broke into restless applause, as they chanted awkwardly to fill the void, she said nothing. When an alarm rang, six minutes and 20 seconds after she’d walked onstage—the same amount of time it took a broken young man to murder 17 people with an AR-15—the intrepid high school senior finished the powerful sermon she’d begun. “Fight for your lives before it’s someone else’s job,” she said.

If 2018 becomes the year that the United States finally begins to tackle its disease of gun violence—an epidemic that steals nearly 100 American lives every day—it will be due not to the good sense of elected officials, but rather to the courage, tenacity, and sheer eloquence of students like Emma González. It will be due to 11th-graders like Cameron Kasky, who along with Stoneman Douglas classmates Jaclyn Corin and Alex Wind launched the #NeverAgain crusade and helped plan the historic March for Our Lives rally in Washington, which was mirrored by gatherings around the world. It will be due to 11-year-olds like Naomi Wadler, who reminded millions of people on that same day of something that should never have needed a reminder: that young African-Americans who die in such overwhelming numbers from gun violence aren’t “simply statistics” but instead vibrant lives “full of potential.” It will be due to 21-year-olds like Columbia student Nza-Ari Khepra, who cofounded two efforts to bring attention to gun violence—Project Orange Tree and the Wear Orange campaign—which she hopes will inspire other young people to engage in a conversation about this scourge. (The idea of wearing orange came about because it’s the color hunters wear in the woods to protect them from becoming targets themselves.)

“These kids are articulating so forcefully and passionately the need for change, and it has sparked something well beyond just Marjory Stoneman Douglas,” says Kristin Brown, copresident of the Brady Campaign to Prevent Gun Violence. “You see it across the country with kids now wanting to get involved. And I think they’ve really claimed their voice—almost as a generation—around this issue. This has become their cause, and I think it’s a wonderful thing.”

On the legislative front, she says, the students have already driven substantive change. New Jersey, Vermont, and, yes, Florida, have passed various reforms to curb gun violence, says Brown, who has been fighting for reforms such as national background checks and limits on assault weapons since 1990. She thinks we may now be near a tipping point: “It has really caused an unprecedented number of bills to be introduced in many more states than we would have even had on our radar screen,” she says. “There’s something real here.”

This article is part of the World’s 50 Greatest Leaders feature, our annual list of world-changing leaders in business, government, philanthropy and beyond. Click here to see the other leaders on the list.