As Dr. jeffery Record wrote in an Army War College report less than a year after the invasion of Iraq:
"In the wake of the September 11, 2001, al-Qaeda terrorist attacks on the United States, the U.S. Government declared a global war on
terrorism (GWOT). The nature and parameters of that war, however, remain frustratingly unclear. The administration has postulated a
multiplicity of enemies, including rogue states; weapons of mass destruction (WMD) proliferators; terrorist organizations of global,
regional, and national scope; and terrorism itself.
It also seems to have conflated them into a monolithic threat, and in so doing has subordinated strategic clarity to the moral clarity it strives for in foreign policy and may have set the United States on a course of open-ended and gratuitous conflict with states and nonstate entities that pose no serious threat to the United States. Of particular concern has been the conflation of al-Qaeda and Saddam Hussein’s Iraq as a single, undifferentiated terrorist threat. This was a strategic error of the first order because it ignored critical differences between the two in character, threat level, and susceptibility to U.S. deterrence and military action.
The result has been an unnecessary preventive war of choice against a deterred Iraq that has created a new front in the Middle East for Islamic terrorism and diverted attention and resources away from securing the American homeland against further assault by an undeterrable al-Qaeda. The war against Iraq was not integral to the GWOT, but rather a detour from it."
http://www.strategicstudiesinstitute.army.mil/pdffiles/PUB207.pdf