The situation is poised to get much worse because Islamist activity is no longer isolated to the geographic periphery of the Russian Federation. Extreme fundamentalism is also on the rise in Russia’s heartland. In Tatarstan and Bashkortostan, both majority-Muslim republics near the Ural Mountains, moderate Islamic clerics have been targets of assassination attempts. Identification with al Qaeda and other radicals, meanwhile, is on the rise. Motorcades bearing the black banners of jihad are now a regular occurrence on the streets of cities in those regions.

Compounding this trouble is the fact that this sprawling nation is on the cusp of major ethnic and religious transformation. Russia’s population is constricting rapidly. A recent study by researchers at Russia’s Institute of Socio-Scientific Expertise predicted that under a “worst case scenario” the country’s population could shrink by nearly a third—to 100 million from roughly 142 million today—by the middle of the century.

Russia’s Muslims, however, are faring comparatively well. At some 21 million, they make up roughly 16% of the country’s current population. By the end of the decade, one in five Russians will be Muslim—and by midcentury, every other Russian might be.