A miter saw having a base and an arm that pivots toward the base is disclosed. A blade is supported by the arm, and is designed to cut workpieces resting on the base when the arm and blade pivot downward. The saw includes a detection system configured to detect one or more dangerous conditions between a person and the blade, such as when a person accidentally touches the spinning blade, and the saw includes a reaction system to urge the arm and blade away from the base when the dangerous condition is detected.