"Throughout all this debate and conflict, Sistani tried to stay above the fray. He continued to keep his eyes on the big prize: delivering Iraq to the Shia and protecting Shia identity by ensuring its embodiment in the new constitution and the state arising from it. He did not get bogged down in debates over who was Iranian and who was Iraqi. Most Iraqi Shias were clearly Arabs, but that identity was surfacing in a new way, different from the way in which Arab nationalism and Ba'thism had always envisioned it.
The bombing of markeplaces, police stations, mosques, and open-air religious gatherings meanwhile occurred almost daily, generating a tale of sorrow and rage that would tear Shias and Sunnis apart. On August 31, 2005, about a million Shia pilgrims gathered at the shrine of Kazemiya in Baghdad to mark the anniversary of the death of the seventh imam, who is buried there. The crowd stretched from the mosque across the River Tigris to Sadr City, clogging the bridge over the river. A mortar attack on the crowd early in the day killed sixteen and injured many more. The crowd was on edge when some person or persons on the bridge spread a rumor – Shias believe deliberately – that there was a suicide bomber in their midst. Anxious and fearful, the crowd panicked. In the ensuing stampede, more than a thousand people died; some were trampled to death, while others drowned after jumping into the river. Most of the victims were women and children. The incident showed the extent to which the insurgency could disrupt Shias' lives and turn their commemoration of the death of their imams into a new occasion for mourning. It also underscored the inability of the Iraqi government to contend with the violence, and even more the extent to which the insurgency had succeeded in instilling fear in Shias' hearts and minds.
Urged by Sistani and his clerical network not to respond in kind, Shias showed tremendous restraint. Their patience was taxed, but their sense of distinct identity only grew under the onslaught of Sunni terror (a good deal of which was the work of non-Iraqis, such as the terror group run by Abu Musab al-Zarqawi, the Jordanian Salafi who masterminded the insurgency's most violent excesses). Attitudes on the street hardened, as did Shias' determination to stay in charge of their own destiny. Even where relations between Shia and Sunni neighbors remained friendly, distrust of Ba'thists and the Wahhabi influence on Sunni clerics intensified.
Increasingly, Shias saw Sunnis as vicious brutes and ridiculed their historical claims to grandeur. In Basra and other places in the south, Sunnis came under attack. Targeted killing of Sunni clerics and community leaders served notice to others to move away. These acts, which some blamed on the Badr Brigade, reflected the mood on the street. Anger and prejudice were rising on both sides of the sectarian divide. The manner in which Shia identity was taking for was directly tied to the intensity of the sectarian conflict.
This became clear when a bombing attack on the Shia Askariya shrine (where the tenth and eleventh imams are buried, and wherefrom the Twelfth Imam went into hiding) brought sectarian conflict into the open. Hundreds died as angry Shias and Sunnis attacked mosques, killed clerics, and abducted and murdered civilians. Despite calls for calm the violence continued to rage, exposing the deep sectarian fissures that were shaping Shia identity and politics."
-Vali Nasr, The Shia Revival