No Smoking Gun: The Brady Act, Medical Cannabis, and Violent Gun Crime

Cameron Ellis (University of Iowa), J. Bradley Karl (Florida State University), Rhet A. Smith (University of Texas at El Paso), No Smoking Gun: The Brady Act, Medical Cannabis, and Violent Gun Crime (2023):

Under the federal regulations of the Brady Act, individuals using medical cannabis are prohibited from legally purchasing firearms. However, 36 states permit medical cannabis use, compelling individuals to choose between legally possessing cannabis or guns, but not both. This backdoor ban allows us to utilize the differential timing of cannabis legalization to identify the impact of gun purchase restrictions on gun crime. Using difference-in-differences and triple difference-in-difference models on FBI Uniform Crime Reports data, we find medical cannabis reduces assaults and robberies with firearms by 5\%, relative to knife crimes. We find no impact on knife crimes alone, suggesting substitution away from crime instead of towards other weapons. Further analysis shows the effect is concentrated near cannabis dispensaries, supporting our mechanism.