I've found this paper quite informative so I'm posting it up here. It's by Toby Dodge, who is Senior Consulting Fellow for the Middle East at the International Institute for Strategic Studies, and a Reader in International Politics at Queen Mary, University of London. 'The Causes of US Failure in Iraq', Survivial, vol. 49 no. 1, Spring 2007. http://www.channel4.com/news/microsites/I/the_iraq_commission/pdfs/dr_toby_dodge_submission.pdf
