A 30-year-old Saudi prince could jump-start the kingdom — or drive it off a cliff

The tensions unsettling the Saudi royal family became clear in September, when Joseph Westphal, the U.S. ambassador to Riyadh, flew to Jiddah to meet Crown Prince Mohammed bin Nayef, nominally the heir to the throne. But when he arrived, he was told that the deputy crown prince, a brash 30-year-old named Mohammed bin Salman, wanted to see him urgently