Beyond oil and reserves, Russia running on empty

MOSCOW (Reuters) - For all the sanctions Western leaders can throw at Russia, the biggest threat to President Vladimir Putin's ability to back separatists in east Ukraine is something beyond his or their control: the price of oil.

    With Russia's $2 trillion (1.19 trillion pounds) economy heavily dependent on crude exports, oil prices are always closely monitored by the Kremlin, but the government is particularly wary now as tensions with the West mount and sanctions ratchet up.