Sam Dagher at the CSM has a good article on the potential detrimental effect of having large numbers of US troops in close quarters with Iraqi civilians. Invariably, in a counter-insurgency conflict, civilians are going to be killed by US forces. This is particularly true of a country like Iraq, in which the general populace tends to be quite heavily armed. The Surge exacerbates the regular problem of US-caused civilian deaths by putting troops who are less well trained and less well equipped than they should be in extremely dangerous situations. While it’s true that the Surge could reduce civilian deaths in Baghdad by making it more difficult for sectarian militias to operate, it’s not a 1-1 swap; every person killed by the US causes more damage than each person saved by US forces. Moreover, since much of Baghdad seemed to rely on the sectarian militias for defense, even their suppression is double-edged.
Oh, and the insurgents are very, very desperate. If they weren’t, a suicide bomber wouldn’t have just killed nine Americans and wounded twenty more in Diyala province.