going to iraq who were the key players?

Who were the key actors involved in the decision-making to go to Iraq and how did their ideas evolve?
Why were some actors involved and others excluded from the decision-making to go to Iraq and did the exclusion of some actors affect the decision that was made?
How did professional careerists and political appointees who opposed the war attempt to influence the thought about going to war and why did they fail?

should be 75 to 150 words, but may go longer depending on the topic.