Precisely. How do you keep crazy people from having guns when the only suitable definition of crazy is somebody that has done something terrible (which obviously is too late).

There are ways to intervene short of throwing someone in a sanitarium, and better causes for intervention than holding a fringe opinion.

> The Secret Service found that when youth plan targeted violence, they often tell at least one person about their plans [and] offer specifics before the event

> most attackers engaged in some behavior prior to the incident that caused concern or indicated a need for help

https://www.ojp.gov/ncjrs/virtual-library/abstracts/preventi...