Many Iraqis look to gunmen as protectors
What most are missing, I think, is that no one is in control of Iraq. Not the US, not the militias, not the insurgents. Moreover, the militias and insurgents probably have some interchangeable members and morph into coalitions and splinter groups constantly.
Sooner or later, groups will morph into larger groups, and then one will become dominant. It is a given they will be unfriendly to the U.S. Nor does the U.S. have the power to partition Iraq and it is delusion to believe they do.