Once considered a schoolyard rite of passage, bullying has stoked a national conversation and captured the attention of lawmakers and courts. In the U.S., at least one in four students is bullied at school, federal statistics show. At least 70 percent of students say they have seen bullying at school. And the proliferation of social media — and cyberbullying — has intensified the scrutiny on how, how often, and how viciously students can taunt their peers.