With much of the world’s oil supplies out of action, Russia could step in to meet demand in China and IndiaA prolonged energy crisis triggered by the widening war in the Middle East could offer an economic lifeline to Russia’s war machine at a moment when it was beginning to show signs of strain.The sharp weakening and possible collapse of the regime in Iran would deprive the Kremlin of one of its closest regional partners. But that setback could be outweighed by an economic windfall if disrupti...