Jackie Corin helped create #NeverAgainMSD, which evolved into MFOL. She will never command a stage like Emma González, match the fire of David Hogg’s Twitter feed, or keep the faithful giggling like Cameron Kasky, who delighted in telling reporters that he thought up the name #NeverAgain while sitting on the toilet in his Ghostbusters pajamas. But Jackie is a natural implementer and a driving force behind the scenes.

In its effort to make gun control a priority for midterm voters, MFOL has mobilized on two fronts: inspiring a massive following, and then building a network across thousands of high schools and colleges to drive young people to the polls. The first half was widely publicized—Emma alone has 1.6 million Twitter followers. But while she, David, and several others light up the Internet, Jackie tackles the logistics. Movements are born from hope, but they are built brick by brick. That’s Jackie’s department. If these kids rock the vote on Election Day, Jackie Corin will be a crucial reason why.

The Parkland uprising seemed to erupt out of nowhere, but it had been two decades in the making. The school-shooter era began at 11:19 A.M. M.D.T., on April 20, 1999. I arrived at Columbine High School, in Littleton, Colorado, a little after noon that day to cover the aftermath. The pain I witnessed is seared into me, but nothing prepared me for the next morning, when I saw the faces of the kids who had survived. Their eyes were dry, their faces slack. Their expressions had gone vacant. That’s why I’m still on the story two decades later. I never wanted to see that look again, but what we see today is worse: unsurprised survivors, kids who expected something like this.

The media coverage of Columbine was unprecedented. CNN logged its highest ratings ever, and The New York Times covered the story on its front page for 11 straight days. It was an exceptional moment, demanding exceptional action. Law enforcement and the education system responded with some important changes, including the “active shooter protocol,” and then . . . we came to accept it.

There were no vacant stares from the Parkland survivors. This generation grew up on lockdown drills, and they were primed for action this time. Jackie Corin and her friend Cameron Kasky crouched in lockdown for three and a half hours, getting updates on the carnage by text and Twitter, as 17 students and staff were killed around them—long enough to ride the waves of fear to simmering anger. Jackie and Cameron went to bed that night nursing notions that would give birth to a movement.

Speed. That was the first answer to the question on everyone’s lips this spring: Why is this time so different? Jackie, Cameron, and David Hogg started simultaneously, in the hours after the attack, on three separate and distinct paths. That was Wednesday, February 14. By Saturday, they had joined forces with Emma González and other emerging leaders to launch the #NeverAgainMSD movement.

Their efforts have upended the gun-control conversation in the United States, giving two decades’ worth of survivors new hope. “I am in awe of what is happening,” Coni Sanders told me in March. Her father, Dave, was the Columbine teacher who had remained in the building, saving hundreds of students, until he came face-to-face with the killers. He was shot and, hours later, died of his wounds. “It’s working,” Coni told me. “All these years and it’s working.”

“We could very well die trying to do this,” Emma González told me.

It was speed, then it was candor. Shortly after dawn on the morning after the attack, David Hogg was on CNN, calling out adults for failing his classmates. “We’re children. You guys are the adults,” he said. “You need to take some action and play a role. Work together, come over your politics, and get something done.”