In the mid-2000s, a handful of writers started warning, in detail, about the risks a rapidly growing, unassimilated extremist current posed to Europe. Their books were largely dismissed as paranoid, xenophobic, or simply embarrassing to be seen reading.

What's striking, looking back, is what else was being published at exactly the same time: confident, celebrative books arguing that Europe's “soft-power” model was about to overtake America as the world's leading force in the twenty-first century. Those books got the enthusiastic reviews. The warnings got mocked.

Twenty years on, this day asks a simple question: which set of predictions actually held up? Not to gloat, but because getting the answer right matters for whoever's making similar predictions today — and for the communities who are living with the consequences of the warnings nobody wanted to hear.