In 2017, Brandi Levy, a junior-varsity cheerleader at Mahanoy Area High School, in Pennsylvania, was denied a spot on the school’s varsity squad. That weekend, off campus, Levy posted a furious, profanity-filled photo and message about the decision on Snapchat. A student who saw the message showed a screenshot to her mother—the cheer coach. Levy was barred from cheerleading for the rest of the year. The A.C.L.U. helped Levy’s parents file suit against the school in federal court, claiming that Brandi’s First Amendment right to free speech had been curtailed. Last week, four years after that pivotal snap, the U.S. Supreme Court heard oral arguments in the case of Mahanoy Area School District v. B.L. Jeannie Suk Gersen joins Dorothy Wickenden to discuss this contentious case and what it means for free speech in the digital age.