The unknown impact of a host of sensitive anniversaries threatens Vladimir Putin’s tight control of his country If any conclusion can be drawn about Vladimir Putin after his 15 years at the top of Russian politics, it is that he thrives on stress. Beset by uncertainties and difficulties, at least some of them self-inflicted – Ukraine for instance – he has rarely looked more in command or more cheerful than he does now.  To continue to thrive, however, he will need all the fortitude he can muster. And the politics will be at least as troublesome as the economics. This year and next confront him with two interconnected, challenges. The parliamentary (Duma) elections in September are the first. The second is the stream of centenaries, starting with that of Rasputin&rs