The evidence is compelling.

In the most thorough study yet published on the effects of concealed carry laws, a team led by Stanford University law professor John Donohue found that state laws making it easy to carry concealed firearms lead to more violent crime. The Stanford analysis [https://onlinelibrary.wiley.com/doi/full/10.1111/jels.12219] follows a stream of previous studies reaching similar conclusions about so-called right-to-carry (RTC) laws. It’s the most definitive refutation of the “more guns, less crime” thesis promoted by the gun lobby — which, not surprisingly, remains hostile to peer-reviewed research on the causes of gun violence.

Using different statistical approaches, and operating with the most complete data yet compiled, the researchers tested the effects of right-to-carry firearm laws in 33 states that adopted them between 1981 and 2007 — tracking violent crime before and after, and controlling for other factors. The exact conclusions varied depending on the statistical method. The bottom line did not. No matter which model was used, the study found that in states that adopted RTC, “violent crime is substantially higher after 10 years than would have been the case had the RTC law not been adopted.”