Lewis Mizen is your typical teen. He goes to school, hangs out with friends and participates in nearly a dozen extracurricular activities. But Mizen never imagined he’d take on a new role in his senior year at Marjory Stoneman Douglas High School: the role of an activist. After the Parkland shooting that killed 17 people, including his own classmates and friends, Mizen is calling on Americans — both Republicans and Democrats — to have a meaningful conversation about what he calls commonsense gun control.