Republican Rep. Dusty Johnson of South Dakota has decided to sleep with a loaded pistol near his nightstand after the deadly shootings targeting Minnesota state lawmakers and their families over the weekend.

The assassination of a Minnesota state lawmaker and her husband, and the shooting of another lawmaker and his wife, are the latest additions to a long, horrifying list of incidents where politics and violence merged in the United States.

Q&A with Jillian Peterson, professor of criminology and criminal justice at Hamline University and co-founder of The Violence Project