Book excerpt: Compares prior estimates of the size of an occupation force that the U.S. military can sustain in Iraq with the military¿s actual practice up to Oct. 2005. The DoD made policy decisions that increased its ability to sustain a larger occupation force compared with a previous estimate. That includes terminating the U.S. military mission in Bosnia, reducing the U.S. presence in NE Asia, and adopting more demanding goals for how rapidly U.S. forces should rotate through extended deployments. The major difference between the size of an occupation force in Iraq 2003-10/05 and the estimate of the size of a sustainable force derives from DoD¿s practice of deploying active- and reserve-component units at rates in excess of what are considered sustainable. Illus.