"Of course, no one seriously suggests that we should strip every last soldier from Europe, North Korea, and our other overseas deployments. Realistically, then, the maximum number of troops available for use in Iraq is probably pretty close to the number we have now: 300,000 rotated annually, for a presence of about 150,000 at any given time.
The only way to appreciably increase this is to raise the Army's end strength by several divisions, and this is exactly what Kagan and Sullivan think Rumsfeld has been too stubborn about opposing. But as they acknowledge, doing this would take a couple of years — and as they don't acknowledge, it would have made the war politically impossible. The invasion of Iraq almost certainly would never have happened if Rumsfeld had told Congress in 2002 that he wanted them to approve three or four (or more) new divisions in preparation for a war in 2004 or 2005."
I agree with most of what Kevin is saying except for this "if Rumsfeld had told Congress in 2002 that he wanted them to approve three or four (or more) new divisions in preparation for a war in 2004 or 2005" That sentence is predicated on Rumsfeld asking to increase the army's size. As this article suggests, we are currently increasing the Army's size without congressional approval.
"Top Pentagon officials say the Army will pay for a temporary increase in troop levels through emergency supplemental funds in fiscal 2004 and fiscal 2005... Historically, troop level increases are planned and funded with congressional approval through regular appropriations. But last week, the Army's top uniformed official announced an increase of about 30,000 soldiers over the next four years using emergency authorities granted to the administration, in an effort to lessen the burden on soldiers on protracted deployment in Iraq."
My point, that many of the criticisms of troop levels are predicated on the Idea that the US Army HAS NOT increased since the War on Terrorism began. I would not be surprised is the US army is Two divisions larger today, than it was on September 10th 2001.