States that have weakened their firearm permitting system have experienced a 13-15 percent increase in violent crime rates.
Donohue J., Aneja A., and Weber K. “Right-To-Carry Laws and Violent Crime: A Comprehensive Assessment Using Panel Data and a State-Level Synthetic Control Analysis”. National Bureau of Economic Research. (2018). https://www.nber.org/papers/w23510.pdf.