I'm sure this will be studied for years to come, and people will come to the same conclusion the studies after Vietnam came to. The failure of the policy in Iraq was one mans failure and that man is Donald Rumsfield. Just like the failure in Vietnam was Robert McNamara's. It's easy to blaim the generals, but remember the generals were advocating a different approach prior to the invasion. Then Rumsfeld replaced all the generals with his "yes men". Now they blame the generals. The solution to the Iraq war only occurred after President Bush replaced Rumsfeld.
I like President Bush, but I do fault him for not replacing Rumsfeld sooner. History will show Iraq as a great success and people who thought a democracy in the Middle East an impossibility will be proven wrong. However, the US and President Bush will never receive the credit because of the failures of Donald Rumsfeld. People have called McNamara a murderer for his willingness to sacrifice American lives to support his failed policies and refusal to either step down or reverse course. Rumsfeld if far worse because he not only did the above, but did it with such arrogance.