A raid on a police station by British and Iraqi police will be the beginning of the end for al Sadr. Al Sadr had been teamed up with local thugs who infiltrated that local police force. The people in that area were terrified of them.
The point of this international story is al Sadr has made some bad alliances. His poor choices will lead to his downfall one way or the other. Either Coalition Forces and Iraqi troops will fight and defeat them, or Iraqis will simply move away.
Al Sadr has always been a pretender in the world of radical Islam, anyway. It was his father who was the respected Muslim cleric, not him. Al Sadr does not have the educational chops for his father's shoes. His actions imply that he does, though. That weakness will undermine him in the future.