Think of “nationalism,” and you might think of a country brainwashed to hate its neighbors. You might imagine thousands of people sacrificing themselves for a power-hungry dictator. You wouldn’t be alone. Albert Einstein himself called nationalism “an infantile disease, the measles of mankind.”

Political scientists blame it for civil wars and territorial ambitions, from Rwanda and Yugoslavia to Nazi Germany and Napoleonic France. Many economists view it as an irrational distraction from free-market principles, impeding growth and promoting corruption across the developing world. When war broke out in the past, nationalism was often automatically assumed to be a party to the crime, either as a tool that would allow leaders to seduce the masses into fighting, or as fuel that stoked popular outrage. There is no denying it: nationalism has got a bad name.

But this negative publicity confuses what is more often than not an innocuous sentiment. Nationalism is a feeling of unity with a group beyond one’s immediate family and friends. In and of itself, it is not conducive to disastrous wars. The bad rap on nationalism relies almost exclusively on cherry-picked exceptions. These conclusions were drawn without considering the far-more-common cases in which nationalism was not the root of some evil. Moreover, many previous studies on the causes of war lacked one key component: an adequate measure of nationalism. Absent this measure, it is impossible to tell if the brand of nationalism of, say, the Axis powers was more intense than others in the years leading up to 1939. Yet, scholars are quick to blame nationalism for a host of ills.