I don’t know any teacher who doesn’t think they are making classroom education nearly impossible. It is a crisis: Social media, the U.S. surgeon general wrote in an advisory this year, might be linked to the growing mental health crisis among teens. And even if this link turns out to be weaker than some recent research suggests, smartphones are undoubtedly a classroom distraction. Understandably, individual schools and school districts — in Florida, Virginia, Pennsylvania and elsewhere — are trying to crack down on smartphones. Students are required to store the devices in backpacks or lockers during classes, or to place them in magnetic locking pouches. In 2024, these efforts should go even further: Impose an outright ban on bringing cellphones to school, which parents should welcome and support. In educational settings, smartphones have an almost entirely negative impact: Educators and students alike note they can fuel cyberbullying and stifle meaningful in-person interaction. A 14-country study cited by UNESCO found that the mere presence of a mobile phone nearby was enough to distract students from learning. It can take up to 20 minutes for students to refocus. Education Department data suggest that a majority of schools prohibit nonacademic cellphone use during school hours, but the enforcement of those policies is often lax — teachers can’t confront every student or confiscate every device; some report students request bathroom breaks to check their notifications in the stalls. Phones are still in hand between classes, at lunch and recess, and often during instructional time despite putative bans — 97 percent of teens report using their phones during…