* Isidor and Seville Sulzbacher Professor of Law, Columbia Law School, and Professor of Epidemiology, Columbia University.
** Paul J. Kellner Professor of Law, Columbia Law School. Huge thanks to Kyla Magun and Remy Grosbard for all their patience and help. Thanks to Darrel Stephens who generously shared recent data on city-level homicides. Patricio Martinez-Llompart provided excellent research assistance. Special thanks to Nathan Hess for excellent cartography. All opinions and errors are our own.