Americans have long considered Saudi Arabia the one constant in the Arab Middle East—a source of cheap oil, political stability, and lucrative business relationships. But the country is run by an increasingly dysfunctional royal family that has been funding militant Islamic movements abroad in an attempt to protect itself from them at home. A former CIA operative argues, in an article drawn form his new book, Sleeping With the Devil, that today's Saudi Arabia can't last much longer—and the social and economic fallout of its demise could be calamitous