http://www.time.com/time/world/article/ ... -4,00.html
There is another clock, not often mentioned, that sits in the Pentagon. It is the Broken Army clock, the service timeline for an exhausted force. Petraeus and his staff were deeply concerned when rumors of another tour extension, from the current 15 months for soldiers, spread in mid-June. "It would be a last resort," Secretary of Defense Robert Gates told reporters — but troop morale is so iffy that Petraeus quietly urged his commanders to "get the word out" to their soldiers that the extension rumors were false.
According to the Broken Army clock, troop levels will begin to wane in March 2008, no matter what Congress decides in September; the current 20 brigade combat teams will be reduced to 15 by August 2008. There is growing speculation in the military that Bush will try to pre-empt the Petraeus testimony by announcing a gradual drawdown from 20 to 15 combat brigades later this summer. "As if that isn't going to happen anyway," a senior officer told me. "But it may give us some political breathing space" — that is, it may subvert the Democrats' calls for a more rapid withdrawal — "if the President makes a big deal of announcing we're drawing down."