What were the reasons for the reduction in politically motivated terrorism and the increase in religously motivated terrorism?

Let me answer with another few questions: Is there a qualitative difference between the two, and if so, to what degree? Can and should we distinguish political and religious motivation from one another? Do religious and political motives become blurred together so as to be inseparable? What happens when religiously motivated terrorists explicitly express a desire to emulate the Thermidorians of more than two centuries ago alongside their religious figureheads?

http://www.nytimes.com/2001/10/13/arts/the-deep-intellectual-roots-of-islamic-terror.html