"ignoring the uncomfortable fact that most of the worst Islamic extremism and terrorism of the past two decades has tracked back, through funding and religious influence, ultimately, to Saudi Arabia." "Many would agree that the extremist Sunni ideology of Isis is merely a step on from, or the application of, the Wahhabi Islam that is the basis of Saudi Arabia. It is this extremism that is driving the burgeoning sectarian conflict between Sunni and Shia, potentially disastrous on a hitherto undreamed-of scale." (thanks Amir)