War In Baghdad And Basra

It is very hard to know what to make right now of the clashes in Basra and Baghdad between US and Maliki government forces and various Shiite militias. It is not hard to figure out that this is an extremely significant development:

Sadr City, the Baghdad neighborhood that is the center of the Mahdi Army’s power, was sealed off by a cordon of Iraqi troops and what appeared to be several American units. A New York Times photographer who was able to get through the cordon found more layers of checkpoints, each one run by about two dozen heavily armed Mahdi Army fighters clad in tracksuits and T-shirts. Tires burned in the city center, gunfire echoed against shuttered stores, and teams of fighters in pickup trucks moved about brandishing machine guns, sniper rifles and rocket-propelled grenade launchers.

The great question these past few months has been how long the Shiite calm would last. I guess we're beginning to find out.