WITH awful, numbing regularity Americans use high-powered, high-capacity firearms to carry out mass shootings. And with awful regularity, efforts to reform America’s gun laws in the wake of such tragedies fail. (Indeed, a recent paper published by the Harvard Business School found that a mass shooting leads to a 75% rise in measures easing gun control in states with Republican-controlled legislatures.) More than 30,000 people die in shootings in America each year; no other rich country suffers anywhere near that level of gun violence.

Opponents of gun control argue that such figures have things backwards. In their view, widespread gun ownership deters crime, and thus benefits society. Advocates of tighter restrictions on gun ownership disagree: they believe the spur to gun crime from the ready availability of weapons far outweighs the deterrent effects. Social scientists have long struggled to adjudicate, since, on the surface at least, the data are ambiguous.

Pro-gun groups point out that rates of gun ownership tend to be highest in rural, sparsely populated states, where crime rates are low. By the same token,...Continue reading