As he has throughout the Iraqi war, Wretchard at Belmont Club offers up interesting analysis of how coalition forces will likely proceed now that the cease-fire in Najaf has broken down. An excerpt:
It is what must not happen next that matters. The tactical problem facing coalition commanders is how to kill or capture Sadr's forces with Iraqi personnel while avoiding unnecessary deaths and damage to the Shrine. That rules out the textbook solution of leveling it with fires. Because of the subdivided interior of buildings and the fact that Sadr may have wired the Shrine with demolitions a direct assault will probably be excluded for the present. The problem with an assault is that once friendly forces are in contact, one is bound to support them and that imperative will compel the scene commander to order the fires he sought to avoid in the first place. Besieging forces have traditionally used time to weaken resistance without applying direct force. In this case time can also work against the investing forces because Sadr will attempt to run countersiege operations by organizing marches and cavalcades by his supporters to Najaf. Given enough time, he probably reckons that the international media and possibly the United Nations will ride to his rescue. (Heritage site, blah-blah).
Without knowing what the operational commanders will do next, one can still surmise that they will attempt to compress the effects of time by applying unrelenting pressure on the garrison using disturbances, sniping and probes. They would be justified in using nonlethal agents such as CS (tear gas) to stir the pot. Things may still go wrong. Janet Reno's assault on Waco resulted in starting an accidental conflagration that turned the Koresh compound into a charnel house. What is important is to avoid building up the pressure to a climax, to avoid precipitating a self-inflicted Gotterdammerung by Sadr. I suppose one could set up loudspeakers and blast out Koranic verses at levels the EPA would rule illegal, etc. The whole idea is to make a day into an eternity until the days all run together in a jumble.
One hopes that the coalition forces will not vacillate as we seem to have done in Fallujah which has become a festering sore. Once Sadr falls or is taken, the insurgency will have lost a key to whatever legitimacy it still might have with the Iraqi people (although see here and here for Iraqi opinion on al Sadr), and it's disintegration will be accelerated.