In what amounts to a top-down revolution in the House of Saud, an aging king and his son are shattering the monarchy’s long-held tradition of ruling by consensus and accelerating a crackdown on corruption that has caught up scores of royals. The wave of arrests offers the clearest sign yet that the world’s largest royal family is gradually being whittled down to two who matter: King Salman and his 32-year-old son and heir, Crown Prince Mohammed bin Salman, who has ascended to a position of unrivaled power since his father assumed the throne nearly three years ago. Under King Salman, senior princes once thought untouchable have been sidelined from power, silenced—and now also detained. As part of the government’s ongoing corruption investigation, many more royals have had their bank accounts […]