The Iran war exposed a long-simmering feud within the world’s most powerful oil cartel, boiling over this spring when it contended with the biggest oil supply shock in history. Now OPEC faces a fight for its existence. The Strait of Hormuz has started to reopen, and some OPEC nations are clamoring to ramp up oil production The ultimate decider will be Saudi Arabia Unlike Iraq and Kuwait, the Saudis don’t need production to ramp up . The country was able to keep its oil business afloat by bypassing the strait with pipelines that shipped oil to a port in Yanbu...