The Bush administration has said that it's sending 21,500 more combat troops to Iraq, but a new report from the Congressional Budget Office suggests that the actual escalation of the war will be much larger than that.
From the CBO report:
"Over the past few years, [the Department of Defense's] practice has been to deploy a total of about 9,500 personnel per combat brigade to the Iraq theater, including about 4,000 combat troops and about 5,500 supporting troops.
"DoD has not yet indicated which support units will be deployed along with the added combat forces, or how many additional troops will be involved. Army and DoD officials have indicated that it will be both possible and desirable to deploy fewer additional support units than historical practice would indicate. CBO expects that, even if the additional brigades required fewer support units than historical practice suggests, those units would still represent a significant additional number of military personnel.
"To reflect some of the uncertainty about the number of support troops, CBO developed its estimates on the basis of two alternative assumptions. In one scenario, CBO assumed that additional support troops would be deployed in the same proportion to combat troops that currently exists in Iraq. That approach would require about 28,000 support troops in addition to the 20,000 combat troops -- a total of 48,000. CBO also presents an alternative scenario that would include a smaller number of support personnel -- about 3,000 per combat brigade -- totaling about 15,000 support personnel and bringing the total additional forces to about 35,000."