Charleston, South Carolina. Lafayette, Louisiana. Roseburg, Oregon. Colorado Springs, Colorado. Although these towns have little in common, they will be forever linked. In each of them in 2015, an individual with a gun opened fire in public places where people gather: a church, a movie theater, a college campus, and a health clinic.

Because the perpetrators of these and other widely publicized mass shootings are often described in news coverage as mentally ill outcasts, many people and their representatives in Congress view improving mental health services as the key to reducing gun violence.