Underlying the popularity of Muqtada al-Sadr is a phenomenon of mobilization and politicization amongst the Shi'i disinherited classes. While there have always been fractures in the jaysh al-mahdi, Muqtada has been more-or-less in charge of this lower class movement. The fragmentation of the movement augurs for more violence and confusion. For me, the parallel would be the Shi'i community in Beirut from 1984 or so until the late 1980s. American officials who sometimes dreamed of a world without Muqtada never quite understood the cohesive role that he plays.
Shiite militia may be disintegrating - Yahoo! News