Since the cold war started and ended. In the early seventies we backed several monarchies in the middle east and when they were over thrown. We played a huge rolling in providing weapons and training to the freedom fighters when the USSR invaded Afghanistan and unfortunately helped create the very problem we are fighting. We also contradict much of there life styles and teachings which many of them believe we are corrupting their young. You can also look at it as the continuation of the crusades when the church ordered all Catholics of every nation to reclaim the holy land. Or the creation of Israel after WWII, which many Arab nations still to this day hate. I personally don't believe that peace will ever fully come to that part of the world, there are too many people with the own beliefs, religions and thoughts to allow peace to grow and flourish there.