According to the conventional view, President Vladimir Putin's growing authoritarian grip has brought stability and prosperity -- hence his sky-high approval ratings -- even as vast sections of the economy are effectively nationalized and the opposition and media are quashed. These developments create a stable, if overly confident Russia in the short term. But they are also a sign of the nation's underlying combustibility. More than any other country in the world, Russia faces a long-term demographic crisis: The population of ethnic Russians declines by more than one million every year. Meanwhile, the number of Muslims in the country, from the Caucasus, Central Asia and the Middle East, is surging through immigration and high birth rates. The response of many Russians is racist nationalism, in many cases encouraged by the state. The respected human rights group Memorial has linked Kremlin-supported youth group Nashi, which runs summer camps where white, Orthodox, ethnic Russians are encouraged to breed, to numerous hate crimes. As ethnic and religious minorities become majorities in a number of key neighborhoods, districts and towns, a counternationalist backlash brews. Putin and his possible successors know this, and the strengthening of central power is part of a bid to prevent the biggest potential combustion of all: the Balkanization of Russia's over 160 ethnic groups. Yet their clampdown could also exacerbate the tension. Local government restrictions, limiting the number of Muslim vendors at outdoor markets, for example, only serve to deepen minority frustration. Such an explosion in Eurasia would have profound implications for U.S. and European energy security, transnational crime and migration flows across the continent, not to mention the fate of Russia's poorly secured stockpiles of nuclear materials. The administration of U.S. President George W. Bush is wary of failed states, which is a justified concern. But combustible countries that could destabilize entire regions through their inbuilt instability should be the priority.