Given the continent’s record, such an influx would doom any chances for effective assimilation. The only way to avoid both massive Muslim immigration and the collapse of European welfare states would be to raise the retirement age—now as low as 56 (women) and 58 years in Italy and 60 years in France—to 75 years and to create impenetrable borders. The second action is impossible; the first one is (as yet) politically unthinkable. But even if a later retirement age were gradually adopted, mass immigration, legal and illegal, is unavoidable. The demographic push from the southern hinterland and the European Union’s economic pull produce an irresistible force.

Two dominant scenarios implied by this reality are mutually exclusive: either full integration of Muslim immigrants into European societies, or a continuing incompatibility of the two traditions that through demographic imperatives will lead to an eventual triumph of the Muslim one, if not continent-wide, then at least in Spain, Italy, and France. I do not think that the possibility of a great hybridization, akin to the Islamo-Christian syncretism that prevailed during the earliest period of the Ottoman state (Lowry 2003), is at all likely. The continent’s Christians are now overwhelmingly too secular-minded to be partners in creating such a spiritual blend, and for too many Muslims, any dialogue with “nonbelievers” is heretical.

Other fundamental problems will prevent Europe from continuing to act as a global leader. Europe cannot act as a cohesive force as long as its internal divisions and disagreements remain as acute as they have been for the past three decades despite the continent’s advances toward economic and political unification. Yet the ruinous agricultural subsidies, national electorates alienated from remote bureaucracies, Brussels’s rule by directive, and inability to formulate common foreign policy and military strategy are, in the long run, secondary matters compared with the eventual course of the EU’s enlargement. Even an arbitrarily permanent exclusion of Russia from the EU leaves the challenge of dealing with the Balkans, Ukraine, and Turkey. The EU’s conflicting attitudes toward Turkey—among some leaders an eager or welcoming, economics-based embrace, among others a fearful, largely culture-based, rejection—capture the complexity of the challenge.