Friday marks the 25th anniversary of the Sept. 11, 2001, terrorist attacks. While al Qaeda leader Osama bin Laden is dead, the ideology he nurtured and cultivated is alive and well. Indeed, it is perhaps even more pervasive in Islamic societies than it was a quarter-century ago.

Saudi Crown Prince Mohammed bin Salman slips into the pattern of many predecessors. He seeks to balance reform at home with appeasing Islamists by supporting jihadi groups abroad. From Libya to Yemen to Sudan and Somalia, Saudi Arabia promotes the Muslim Brotherhood and other extremist groups. Turkey, Pakistan, and Qatar trade personal and business ties with senior politicians to buy immunity from accountability for terrorist financing.