One spark that has reignited the debate over gun violence in recent years was the 1998 publication of Yale economist John R. Lott Jr.’s provocatively titled book More Guns, Less Crime. In it, Lott challenges the conventional wisdom regarding gun violence by arguing that communities are safer when more people are allowed to own and carry guns. He and researcher David Mustard compared crime data from ten states and found that violent crime rates were lower in states that allow virtually all gun owners to obtain permits to carry concealed weapons in public. “Criminals are motivated by self-preservation, and handguns can therefore be a deterrent,” explains Lott. “When guns are concealed, criminals are unable to tell whether the victim is armed before striking, which raises the risk to criminals of committing many...