With a big push from Governor Cuomo, the New York State Legislature passed a law this week requiring psychotherapists to report any client thought "likely to engage" in violent behavior, so authorities can confiscate weapons. That has produced a backlash from some practitioners. President Obama and Congress are looking for ways for mental health agencies to share information so law enforcement can take action. Is the next step preventive detention for people who've never committed crimes? Is prediction possible, or is there no choice but to wait for violence to happen? We hear about the scientific, legal and ethical controversies provoked by outrage over a rash of mass killings.