California Gov. Gavin Newsom is sending letters to school districts, urging them to restrict smartphone use on campuses. In South Carolina, education officials are expected to approve guidelines to restrict student phone use. The efforts are part of a broader push by states across the country to address digital distractions in the classroom and the impacts of social media on the mental health of teens. Cellphone bans are already in place at many schools but are not always enforced. The issue has garnered renewed attention after the U.S. surgeon general called on Congress to require warning labels on social media platforms that address mental health risks for young people.