Insurgent Defensive Plan
The insurgents are composed of a variety of groups with varying levels of coordination between them. This is the estimate of the US. With such a decentralized command structure, controlling a defense is impossible. Instead, you have to give very broad, general guidance to your personnel and hope they follow it. In this case, the defensive plan would make a series of nodes all over the city. Each node would consist of a weapons cache, or an excellent piece of terrain for firing at the invaders, or othe features that would make it ideal for a fighting position. Between these nodes would be multiple avenues of approach, all interwoven in a grid. These could be surface streets, tunnels, holes blown through the walls of buildings, sewers, etc. The plan would be for insurgents to attack, then displace very quickly to the next position, before the firepower of the US can be trained upon them. All of this could have been rehearsed so that fighters could get between positions even at night. This nodal defense would be more effective if a) insurgent forces could communicate as to which positions had been reduced by the Americans and b) insurgents waited until US forces bypassed them before attacking.