As written by Juan Cole

The complexities of Iraq are underlined by the increasingly flourishing condition of the holy Shiite city of Najaf south of Baghdad, which is fairly secure and peaceful. Its pharmacies have medicines, it has 20 hours of electricity a day, and US troops withdrew last September to a base well away from the city, reducing the chance of provocations. Plans are going forward for an airport. Some 3 million pilgrims a year are already coming, mostly from Iran but also from Lebanon, Kuwait, Pakistan and elsewhere, to visit the shrine of Imam Ali. The combination of resources from Iran and from the wealthy merchants and shopkeepers of the city, the calming influence of Grand Ayatollah Sistani, who resides there, the loyalty of the tribal levies to Sistani, the induction of members of the Badr Corps paramilitary into the provincial police and government military, and the defeat of the radical Mahdi Army of Muqtada al-Sadr in August 2004 by the joint efforts of Sistani, the other grand ayatollahs and the US Marines, have all contributed to this current flourishing situation. Ironically, Najaf's success is a rebuke to Paul Bremer, who once cancelled an election there because he feared Iranian influence in the city. In the end, Iran wins this one.

AP explains the long relationship between the Iraqi Shiites and their Iranian co-religionists.