The battle in southern Iraq between government forces and Basra militiamen not only demonstrates how fragile are the security gains of the US troops “surge” of the past year. It could be the prelude to a deadly new phase in Iraq’s multi-cornered civil war, sucking American (and residual British) forces into the struggle for power within the majority Shia community.

Ostensibly, the Iraqi national army offensive is to regain control of Basra, the gateway to the Gulf for Iraq’s oil industry, which fell into the lawless clutches of competing Shia militias while under British occupation. In that sense, the Basra push would seem unobjectionable: it is not only the right but the duty of any national government to extend the rule of law to all its citizens. This is, furthermore, the biggest operation mounted by Iraqi forces on their own.