BAGHDAD - Maj. Arthur Vidal, a big, mustachioed soldier with the gusto of an operatic baritone, strides helmeted and flak-jacketed into the dingy foyer of the Sadr City District Advisory Council building, and sums up the scene before him. "Ah, welcome to Democracy 101!" booms the civil-affairs officer, before adding, "Make that Democracy 101 - Phase 2." On this recent afternoon, the US-created district council for Sadr City - a rundown section of Baghdad with exhausted infrastructure, 2 million people, and too few jobs - is to elect a new chairman. The previous chairman, Mohammed al-Kaabi, was shot and killed...