Roots of terrorism
The causes of terrorism--at least the predominant Islamist version--are rooted in a radical Muslim philosophy that is being widely taught in many Muslim nations, and more than a few non-Muslim ones. You can't suppress these teachings any more than you can bail water with a sieve, but you can try and encourage more prosperous and democratic institutions in these nations that would help reduce the fertile ground such teachings grow in.
This may be the prime goal in Iraq.