It is forgotten that Paul Wolfowitz told Congress that the US would be down to only a division (~20,000 men) in October of 2003. Then it is forgotten that the Pentagon announced a draw-down from 135,000 to 110,000 in spring of 2004 (just before the Bush administration decided in its wisdom to"kill or capture" Muqtada al-Sadr). That draw-down didn't happen. Why? The security situation didn't allow it.

So the fact is that Rumsfeld and Casey have no idea if the situation will permit the US to withdraw substantial numbers of troops by next summer.