GFor much of European history, empire was the normal political arrangement: Large, polyglot, multiethnic and eventually multireligious, with a monarch on top and a jostling confederation underneath.
Then came modernity, democracy and nationalism, and the “nations” of Europe — half-real, half-invented — demanded self-determination and self-rule. 

Between 1914 and 1945 (with a final act in the Balkans in the 1990s), this led to world-historical disaster, mass exterminations, ruthless wars for mastery. But out of those conflicts came a new kind of hybrid order. The nations would have self-rule, within borders redrawn by war and ethnic cleansing. But they would be supervised by a kind of postmodern empire, an imperial bureaucracy without the emperor — the European Union.

The outlier, as always, was Great Britain. Like its rivals, the United Kingdom lost its overseas colonies, but it kept much of its domestic empire, the several nations — English, Scottish, Welsh and Ulster Irish — that still share a flag and crown. And as befits its anachronistic status, Britain has held itself somewhat aloof from the European Union’s postmodern imperium, joining the union but not its common currency.

These distinctive arrangements have been good for the U.K. overall. Remaining a united kingdom has magnified its global clout, and being in the E.U., but not fully of it, has spared it the worst of the continent’s Euro-driven woes. 

But neither arrangement may last much longer. In the headlines, last week’s British elections were a big victory for David Cameron’s Conservatives. But the deep winners were the forces of nationalism, Scottish and English, which suddenly have the United Kingdom as we know it on the ropes.