Every leader in Russia's more than 1,000 years of history has faced the same problem: The unwieldy nation is inherently unstable, regardless of what type of system governs it. And for all his administration's bravado, President Vladimir Putin is no exception. The challenges he faces today, as he nears the end of his 17th year in power, are eerily reminiscent of those that heralded the collapse of the Soviet Union and the Russian Empire before it. But Putin is a savvy pupil of history. Drawing from his predecessors' failings, he may be able to defer his administration's demise, or forestall it altogether....