Winston Churchill once famously called Russia "a riddle wrapped in a mystery inside an enigma." Viewed from Washington, or any Western capital, Churchill's observation still rings true in today's post-Soviet era. On May 7, Dmitry Medvedev became Russia's third president. But no one knows how much clout he'll exercise, given that he appointed his powerful predecessor, Vladimir Putin, as prime minister, a post that until now has been only marginal. Medvedev vows to fight corruption, strengthen the judicial system and reduce the vast country's bloated, entrenched bureaucracy, but so far his power base remains a mystery, as does his future relationship with Putin. Also a mystery: who the next U.S. president will be and how he will deal with the Kremlin's new power-sharing arrangement.