IT TOOK MORE than 30 years for BP, a British energy firm, to build its Russian business. It took less than four days to decide to dismantle it. As Vladimir Putin’s forces invaded Ukraine early on February 24th, the logic of BP’s 20% stake in Rosneft, Russia’s state-owned oil giant, began to collapse. BP’s board met to discuss the matter on February 25th; later that day Britain’s business secretary, Kwasi Kwarteng, expressed the…