On the dust-blown plains of central Iraq, Qawliya had long held a notorious reputation as a haven for prostitution, drug dealers and gun runners - until the village was reduced to rubble and its population driven from their homes. The attack that destroyed Qawliya was launched by the Mahdi Army militiamen of Moqtada al-Sadr, the young clerical firebrand who has become the voice of anti-American discontent for many of the country's Shia Muslim majority. It was this brutal display of Mahdi Army muscle last month - combined with the increasing power wielded by its Islamic sharia law courts - that...