Schools across the country are rethinking “zero tolerance” discipline policies under which children have been suspended, even arrested, for minor offenses like cursing, getting into shoving matches and other garden-variety misbehavior that in years past would have been resolved with detention or meetings with a child’s parents.

These reappraisals are long overdue. Studies have shown that suspensions and expulsions do nothing to improve the school climate, while increasing the risk that children will experience long-term social and academic problems. Federal data also indicates that minority students are disproportionately singled out for harsh disciplinary measures.

These policies date back to 1994, when Congress required states receiving federal education money to expel students for bringing guns onto school property. States and local governments broadened and distorted this mandate to expel children for minor infractions. At the same time, schools began stationing police officers in hallways, which also increased arrests for nonviolent behavior.

The scope of the problem became clear three years ago when the Council of State Governments Justice Center, a nonprofit policy group, issued a study of school discipline polices in Texas. It showed that nearly 6 in 10 public school students were suspended or expelled at least once between seventh and 12th grade. But only a tiny fraction of the disciplinary actions taken against students were for serious criminal conduct requiring suspension or expulsion under state law.