In a new report, "Government Legitimacy, Social Solidarity, and American Homicide in Historical Perspective," for the Harry Frank Guggenheim Foundation, Professor Randy Roth writes, “When citizens believe their government is stable and legitimate, when they feel a strong bond with their fellow citizens, and when they believe that their society’s social hierarchy is just and that violence isn’t necessary for respect, homicide rates can fall.”

The report begins:

"Why has the homicide rate in the United States risen by 60% since 2014, from 4.9 to 7.8 persons per 100,000 per year? And why, more broadly, have homicide rates changed over time in human communities and varied from one community to another? Historians and social scientists can’t perform controlled experiments on societies that are changing in many ways at the same time. We can’t measure the impact of a specific change while holding everything else in the human experience constant. We can’t go back to the 1850s, for instance, and uninvent modern breechloading handguns to see if the United States would have the high rates of homicide and armed robbery it does today if its citizens were equipped with nothing more than single-shot, muzzleloading pistols. Our only hope is to engage in 'non-experimental empirical research'—to study societies across vast stretches of time and space, looking for deep patterns in human behavior."

Read the full report.