We all want safe and welcoming school environments where students can learn and teachers can teach. But two recent disturbing examples of extreme reactions to student conduct have brought the negative effects of such responses into sharp relief. That is why many of us have called for re-evaluating the zero-tolerance policies for student misbehavior adopted throughout the nation over the last two decades. These policies were promoted by people, including me, who hoped they would create safe learning environments for students by freeing them from disruptions by misbehaving peers. We were wrong.