There is actually no simple correlation between states’ homicide rates and their gun-ownership rates or gun laws. This has been shown numerous times, by different people, using different data sets. A year ago, I took state gun-ownership levels reported by the Washington Post (based on a Centers for Disease Control survey) and compared them with murder rates from the FBI: no correlation. The legal scholar Eugene Volokh has compared states’ gun laws (as rated by the anti-gun Brady Campaign) with their murder rates: no correlation. David Freddoso of the Washington Examiner, a former National Review reporter, failed to find a correlation even between gun ownership in a state and gun murders specifically, an approach that sets aside the issue of whether gun availability has an effect on non-gun crime. (Guns can deter unarmed criminals, for instance, and criminals without guns may simply switch to other weapons.)

For good measure, I recently redid my analysis with a few tweaks. Instead of relying on a single year of survey data, I averaged three years. (The CDC survey, the best available for state-level numbers, included data on gun ownership only in 2001, 2002, and 2004. Those were the years I looked at.) And instead of comparing CDC data with murder rates from a different agency, I relied on the CDC’s own estimates of death by assault in those years. Again: no correlation.