"If the population is the sea in which the guerrilla fish swim (Mao's dictum), then the more fish the better (Robb)"Multiple car bombs were detonated in the Baghdad district of Kadhimiya, a half a mile from the Abu Hanifa shrine (Baghdad's most revered Shiite shrine). This is just the latest campaign to force more fragmentation of Iraq's social systems. The upshot being that in this type of guerrilla war, the more social division, the better.
There's safety in numbers...
Social systems disruption creates the fragmentation that promotes the growth of new guerrilla/militia groups. The more groups there are, the more difficult it is for US forces to focus on any given group (and given the number of attacks from Mahdi army splinter groups, that is working). It also promotes the development of more allies in the open source war, particularly due to a fear of violence from rival groups. This isn't a civil war, it's manufactured anarchy.