Since 2016, Andrew Marantz has been reporting on how the extremist right has harnessed the Internet and social media to gain a startling prominence in American politics. One day, he was contacted by a woman named Samantha, who was in the leadership of the white-nationalist group Identity Evropa. (She asked to be identified only by her first name.) “When I joined, I really thought that it was just going to be a pro-white community, where we could talk to each other about being who we are, and gain confidence, and build a community,” Samantha told him. “I went in because I was insecure and it made me feel good about myself.” Samantha says she wasn’t a racist, but soon after joining the group she found herself rubbing shoulders with the neo-Nazi organizer Richard Spencer, at a party that culminated in a furious chant of “seig heil.” Marantz and the Radio Hour producer Rhiannon Corby dove into Samantha’s story to understand how and why a “normal” person abandoned her values, her friends, and her family for an ideology of racial segregation and eugenics—and then came out again. They found her to be a cautionary tale for a time when facts and truth are under daily attack. “I thought I knew it all,” she told them. “I think it’s extremely naive and foolish to think that you are impervious to it. No one is impervious to this.”

Samantha appears in Andrew Marantz’s new book, “Antisocial: Online Extremists, Techno-Utopians, and the Hijacking of the American Conversation.”