The scene in classrooms around the country is similar: Kids are on their phones, even when school rules forbid it. Teachers say they see students on Snapchat, listening to music and even watching Netflix in class, among countless other examples of how smartphones distract from teaching and learning. Increasingly, educators are speaking with one voice on the question of how to handle it: Ban phones during classes. A growing number of leaders at the state and federal levels have begun endorsing school cellphone bans and suggesting new ways to curb access to the devices.