On June 23, millions of United Kingdom citizens will vote to leave the European Union. And millions of others will vote to remain. If the leavers win, the UK and EU will begin a methodical divorce that many analysts expect to destabilize the nation and the continent.

All of which might happen eventually, no matter what the UK decides. The so-called Brexit vote is the culmination of years of growing disillusionment—mostly from older and working class Britons—with the European Union's trade agreements and open border policies. It is also part of a larger trend. Across Europe, populist parties have been fighting to regain sovereignty from the EU. The problems of each country, and of the European Union itself, are contemporary, specific, and complicated. But they fit into a model that some scientists have recognized as symptomatic of a civilization on its way towards disintegration.

The European Union began after World War II as set of trade agreements between five countries. Nations with close business ties, the thinking went, would probably be less likely turn squabbles into wars. Over 60 years, the compact has grown into a proper government across 28 member nations, regulating all those things that governments regulate: economy, labor, environment, migration. "I think of the European Union as an empire," says Peter Turchin, an evolutionary anthropologist at the University of Connecticut. "The EU is unusual because it was constructed without conquest, but in terms of functionality it is not unlike other historical examples."

Turchin describes historical empires as large-scale, multi-ethnic conglomerations—ones that wouldn't come together except under a mighty ruling class. And across those different empires, Turchin and his anthropology colleagues look for commonalities. How do policies developed by the ruling class, for example, affect the general population's ability to weather recession or disease? Then they develop mathematical models that strive to explain how civilizations rise and fall.

"Large empires are groups of states glued together by cooperation," Turchin says. In a successful civilization, the ruling class cooperates among itself to create functional rules. It also cooperates with the general population to make sure those rules keep everybody reasonably happy, employed, and safe from harm. In turn, the general population cooperates by not rising up and overthrowing The Man. "One of the signs you see in civilizations going the wrong direction is where the elites make policy choices that bring about increasing inequality," says Turchin. When these unequal policy choices meet some kind of spark—say, an economic recession—they turn into torches for the disaffected general population. The civilization then shakes itself apart, or is toppled by a suddenly stronger external force.

Scholars often argue about the specifics. But Turchin thinks a wide view of world history will show that lack of cooperation between rulers and ruled helped bring bring about the end of the Russian Tsars, the French Monarchy, the British Empire, and many others.