The generals on the ground don't want more troops:
MCCAIN: Did you note that General Zinny who opposed of the invasion now thinks that we should have more troops? Did you notice that General Batise, who was opposed to the conduct of this conflict also says that we may need tens and thousands of additional troops. I don’t understand General. When you have a part of Iraq that is not under our control and yet we still — as Al Anbar province is — I don’t know how many American lives have been sacrificed in Al Anbar province — but we still have enough and we will rely on the ability to train the Iraqi military when the Iraqi army hasn’t send the requested number of battalions into Baghdad.
ABIZAID: Senator McCain, I met with every divisional commander, General Casey, the core commander, General Dempsey, we all talked together. And I said, in your professional opinion, if we were to bring in more American Troops now, does it add considerably to our ability to achieve success in Iraq? And they all said no. And the reason is because we want the Iraqis to do more. It is easy for the Iraqis to rely upon to us do this work. I believe that more American forces prevent the Iraqis from doing more, from taking more responsibility for their own future.