The massive, overwhelmingly Muslim migrant onslaught on Europe is the most important event of 2015. Its proportions are staggering. The Babylonian captivity affected at most 75,000 Jews, and the Völkerwanderung of the late-Roman era numbered in the hundreds of thousands. It is greater, in numbers within the time frame, than the Moorish, Mongol, or Turkish invasions. It is unprecedented.
Over a million unassimilable, generally unemployable, and often hostile aliens—coming from the greater Middle East and all over Africa—have joined the sprawling Islamic diaspora in the European Union. That diaspora, now numbering over 20 million, has already created hundreds of exterritorial no-go areas—from Malmö in the north to Marseille in the south, from Bradford in the west to Berlin in the east. In Europe, this is the first example of the state-within-a-state phenomenon since Cardinal Richelieu personally commanded the siege and subsequent destruction of the Huguenot redoubt at La Rochelle in 1628.
Last November the E.U. blithely predicted that three million more may arrive in the 28-nation bloc by the end of 2016. Next spring, when sea crossing becomes relatively safe again, the invasion will resume—from Libya into Italy, from Turkey into Greece. This is a process of metahistorical significance: The post-Christian liberal West, which has lost...