Reply #8: Many neighborhoods have already been ethnically cleansed and b/c of US patrols in Baghdad.

[Selatius]

Many vulnerable people have either been forced out or have moved into ethnic/sectarian enclaves, the insides of which are hard to penetrate from the outside by guerrillas/militiamen who belong to other enemy groups.

Simply put, many of the easy targets have been eliminated in the urban areas. It's the countryside that's turning into the war zone now.