Muqtada al-Sadr and the Army of the Mahdi.

• Author: Rosen, Nir

M'uqtada al-Sadr wants to become "the third martyr," if he is not already by the time you read this. His great-uncle, Muhammad Baqir al-Sadr, is known as "the first martyr." A leader of the Shiite movement, Baqir al-Sadr wrote books about Islamic politics and economics to prove that Islam provided solutions to all social questions. He was killed in 1980 for opposing the regime of Saddam Hussein.

The legacy of the first martyr was inherited by his nephew Muhammad Sadiq al-Sadr, who declared himself the wali, or leader of the faithful, a position higher even than Ayatollah Khomeini's. Sadiq al-Sadr focused on the Mahdi, or Shiite messiah, who is expected to return on judgment day. Sadr established a network of followers in towns and villages throughout Iraq during the 1990s. He and his two eldest sons were assassinated by the regime in 1999 for opposing Saddam. So Muhammad Sadiq al-Sadr became known as "the second martyr," and his serene black-turbaned visage dominates the walls of Shiite neighborhoods alongside posters of his uncle and other radical figures like Khomeini.

Immediately following the collapse of the Ba'ath regime a year ago, Sadr's last remaining son, Muqtada, who had been living in hiding, used his father's network to establish offices throughout the country, seizing mosques, religious centers, former Ba'athist headquarters, and even hospitals. Muqtada's representatives provided security and social services, filling the power vacuum. They even changed the name of Saddam City, the vast Shiite slum of eastern Baghdad that is home to about three million people, to Sadr City.

Muqtada attracts alienated and angry Shiites, pitting his movement against the American occupiers and more traditional clerics such as Ayatollah Ali al-Sistani who eschewed political activism. Tens of thousands of devout Shiites attend the Friday prayers in hundreds of mosques throughout the country affiliated with Sadr, listening to sermons unanimous in their hostility to American plans for Iraq.

Muqtada dresses in a black robe and a black turban. He tries to maintain a permanent scowl to give himself more gravity. Unlike other Shiite leaders, whose education bestows upon them a rich vocabulary and an eloquent fus-hah, or classical Arabic, Muqtada speaks in a strong colloquial Arabic, replete with slang and street expressions. His associates are young like him and have the same arrogance when dealing with others. An Iraqi judge issued an arrest warrant for Muqtada last April after his followers allegedly murdered a rival cleric. He is very aggressive and tactless, which is highly unusual for a Shiite leader.

Last June, when Muqtada's name was proposed as a possible member of the American-appointed Iraqi Governing Council, other Shiite members rejected the idea. This snub radicalized Muqtada and his constituency. He gravitated toward Ayatollah Kadhim al-Haeri, his father's top student and intellectual heir, who was living in Iranian exile. Though Muqtada's politics were inchoate, lacking ideology, and seeking only inclusion and power, Haeri was a rigid Khomeinist.

At first viewed by the Shia establishment as...