The House of Saud proclaims that it stands “in the face of those trying to hijack Islam ‎and present it to the world as a religion of extremism, hatred, and terrorism.” In Saudi Arabia, at least, it has increasingly stuck to its word. Afraid that jihadis will overthrow them, Saudi royals have promulgated strict rules for oversight of waqfs, or religious charities, that hitherto funded Islamists at home and abroad. Last October, Saudi citizens were forbidden by decree from supporting the so-called Islamic State (IS), and the kingdom is building a stout 600-mile security fence along its border with Iraq to keep those jihadis out.

But the monarchy’s actions are still largely limited to its own protection. Beyond its borders, Saudi Arabia remains the major source of Wahhabi ideology, which spreads outward to radicalize foreign Muslims. With the death of 90-year-old King Abdullah and the accession of his half-brother, 79-year-old Salman, to the throne, Saudi Arabia should change its ways. ...