R ussia is in the throes of a full-blown currency crisis, with profound implications for its economy, its political system and its relations with the outside world. Even by the standards of emerging market currency meltdowns, the rouble’s gyrations this week have been extreme, plumbing record lows that days — even hours — earlier would have seemed unthinkable. The rout is caused by the plunge in the price of oil, Russia’s major export, and exacerbated by western sanctions imposed in response to Vladimir Putin’s military intervention in Ukraine . But the depth of the […]