In reflecting on the San Bernadino Massacre, what the shooters, Syed Rizwan Farook and Tashfeen Malik, appeared to have in common with other people driven to carry out such mass murders—in many cases white, male, American citizens—appears to be anger, alienation and easy access to semi-automatic assault weapons. Had those weapons and ammunition been harder to come by, perhaps they might have thought longer and harder about other ways to vent their rage.