Charles Kenny looks at how lax American gun laws impact Mexico:
Mexico provides a case study of what happens when more guns meet weak institutions. In the four years following the lapse of America’s assault weapons ban in 2004, 60,000 illegal firearms seized in Mexico were traced back to the U.S. Luke Chicoine, an economist at the University of Notre Dame, estimates that the expiration of the federal assault weapons ban led to at least 2,684 additional homicides in Mexico. Similarly, a study from New York University researchers found that homicides spiked in Mexican border towns after 2004, particularly those most involved in narcotics trafficking. The spike was far less dramatic in towns that bordered California, which had a state-level assault weapon ban that remained in place after the U.S. ban lapsed. A survey of court cases reported in their paper found that 3 percent of trafficked guns came from California, vs. 29 percent from Arizona and 50 percent from Texas.