Yet More Hidden Costs  So it now comes out that the surge isn't just 21,000 troops. From the AP:

Gates said that the request for extra MPs is in addition to the 21,500 combat troops that President Bush is sending for the Baghdad security plan and 2,400 other troops designated to support them.

Gordon England, the deputy defense secretary, told Congress earlier this week that the number of required support troops could reach 7,000.

So, that means, 21,000 + 2,200 MPs + 2,400 other troops = 25,600 extra troops...which could be 29,000. Go figure.