Over at Abu Maq's best COIN related blog ever, Dr. iRack looks at recent reporting on stepped up Iranian support to Shiite militias, particularly those involved in the current battles in Sadr city:
[E]mphasizing Iranian involvement provides a useful public "explanation" for the difficulty U.S. and Iraqi forces have had, thus far, in quelling violence in Sadr City. Blame it on Iran, not Sadr/JAM. Why go this route? Because it allows the United States to maintain the fiction that it is only the "special groups" that are fighting the coalition instead of rank-and-file JAM, thus preserving the illusion that the Sadr "freeze" declared last August--a major (perhaps the major) reason for declining violence during the later part of the "surge" period in 2007--has not collapsed. Maintiaining this public--but almost certainly factually incorrect--stance is important to give Sadr a way to save face and back down.