RIYADH, Saudi Arabia, May 24 — When he was a teenager issuing his own fatwas, Mansour al-Nogaidan ordered his followers to blow up a video store in downtown Riyadh because it was spreading Western corruption. Now, years later, a completely changed man has dropped a philosophical bombshell in the fervent national discussion swirling around the suicide attacks this month against residential compounds here. Mr. Nogaidan said in print that the Wahhabi doctrine prevalent in Saudi Arabia was the root cause of the violence fomented in the name of Islam here and around the world. "The main problem is that these...