Baghdad, Iraq - American officials have been repeatedly stunned and frequently thwarted in the past three years by the extraordinary power of Muslim clerics over Iraqi society. But in the sectarian violence of the past few days, that power has taken an ominous turn, as rival hard-line Shiite clerical factions have pushed each other toward more militant and anti-American stances, Iraqi and Western officials say.
Abdul Aziz al-Hakim, right, head of the Supreme Council for the Islamic Revolution in Iraq, or Sciri, shown Feb. 12 with Adel Abdul Mahdi, an economist and Sciri member who lost his bid to become prime minister. More Photos >
Even Grand Ayatollah Ali al-Sistani, the paramount Shiite cleric to whom the Americans have often looked for moderation, appears to have been outflanked by younger and more aggressive figures.
After a bomb exploded in Samarra at one of Iraq's most sacred Shiite shrines on Wednesday, many young Shiites ignored his pleas for calm, instead heeding more extreme calls and attacking Sunni mosques and killing Sunni civilians, even imams, in a crisis that has threatened to provoke open civil war.
On Saturday, Iraqi political leaders from across the spectrum joined with Prime Minister Ibrahim al-Jaafari in a televised show of unity to try to quell the violence. President Bush telephoned several leaders to urge them to return to talks.
Earlier, as the critical moment of Friday Prayer approached, American officials and their allies were left almost helpless, hoping that Iraq's imams would step up to calm the crisis. But that hope gave way to the realization that the clerics could do as much harm as good, and for the first time since the toppling of Saddam Hussein, the Iraqi authorities imposed a daytime curfew to keep people from attending the sermons.
"Sectarian divisions are not new, and sectarian violence is not new," said a Western diplomat in Baghdad who spoke on condition of anonymity because he did not want to be seen as interfering. "What is different this time is that the Shiites, in a sign that their patience is limited, reacted violently in a number of places."
The violence and new militancy has come in part from a competition among Shiite factions to be seen as the protectors of the Shiite masses. The main struggle has been between the leading factions, both backed by Iran, and their spiritual leaders.
Many of the retaliatory attacks after the bombing were led by Mahdi Army militiamen loyal to Moktada al-Sadr, the Shiite cleric whose anti-American crusades have turned him into a rising political power.
His main rival, Abdul Aziz al-Hakim, a cleric and the leader of the Supreme Council for the Islamic Revolution in Iraq, or Sciri, defended the right of Shiites to respond to the bombing. He has shown a new willingness to publicly attack the American role in Iraq, once the preserve of Mr. Sadr, and he also commands a powerful militia, the Badr Organization.
"There are clerics who are very moderate and who understand what the current situation demands, and there are clerics who have political agendas and who marshal forces for their own gain," said Joost Hiltermann, the Middle East director of the International Crisis Group. "Those are the dangerous ones."
The more political clerics, Mr. Hiltermann added, "are quite willing to push their agendas no matter what it might lead to, including civil war and the breakup of the country."
The violence and escalating rhetoric among Sunnis and Shiites has left the mostly secular Iraqi leaders favored by the United States farther than ever from power.
"I think people are rapidly losing confidence in the political class, and I don't blame them," said Adnan Pachachi, a former foreign minister and a member of the shrinking secular alliance led by the former interim prime minister, Ayad Allawi.
Shiite clerics were not the only ones whose power was on display this week. As the violence escalated after the shrine attack, some Sunni Arab religious leaders tried to rally Sunnis in Iraq and other Arab countries to ever more aggressive stands. Members of the Association of Muslim Scholars, a hard-line Sunni group, have cast the violence as part of a broader struggle between Sunnis and Shiites across the region.
Most religious leaders condemned the violence. But some, including many who also play roles as leading politicians, continued to fuel their followers' sense of grievance about the shrine bombing and the reprisals.
The fact that many hard-line political leaders are also clerics complicates the situation. The Iraqi leaders, for instance, can say one thing to American officials while spreading a different message to a vast network of followers through mosques and militias. After Mr. Hakim on Wednesday accused the American ambassador to Iraq of being partly responsible for the Samarra bombing, he distanced himself from the statement and met with the ambassador, Zalmay Khalilzad.
But on Friday, clerics loyal to Mr. Hakim's political party, Sciri, repeated the accusation against Mr. Khalilzad, and it quickly spread to the street, with some Shiites rallying in the southern city of Basra to demand Mr. Khalilzad's removal.
To some, the crisis of the past few days has underscored a longstanding American failure to reach out effectively to moderate Islamists who might give them better access to the Iraqi masses.
From the earliest days of the occupation in 2003, American officials seemed to place most of their faith in secular figures like Mr. Allawi and Ahmad Chalabi, believing they had popular support. They also gave posts of authority to Mr. Hakim and other conservative religious figures, thinking they would play a lesser role in the new Iraq. But Mr. Hakim and others used their positions to help build their political base.
"The Americans knew what was coming, but they underestimated the power — they thought they could control the power of the clerics," said Hatem Mukhlis, a secular Sunni Arab politician who met with President Bush before the war.
Despite Iraq's relatively secular government over the past century, the country remains a part of the broader Islamic world, where bonds between religion and state are deep.
Iraqi Shiites in particular have rallied around their religious leadership before, most recently in the uprising against Saddam Husseinin 1991, but also earlier, as in the revolt against the British in 1920.
"What's happened over the last three years is that there has been an ongoing crisis," said Laith Kubba, a former adviser to Prime Minister Jaafari who is now out of politics. "Even many Iraqis didn't accurately foresee the situation, that in an Iraq so highly polarized, religious leaders would become the rallying points."
Clerics have never been as influential among Sunnis in Iraq, who lack the religious hierarchy of the Shiites. Partly for that reason, the Sunnis were unable to organize as effectively as the Shiites, who dominated the January 2005 elections.
But the example of the Shiites, who formed a powerful political alliance under Ayatollah Sistani's guidance, pushed Sunnis toward their own religious leaders in the December vote.
"In the last election, they saw themselves in danger, so they decided to elect a Sunni list," said Saleh Mutlak, a Sunni Arab leader whose secular party received far fewer votes than the Iraqi Consensus Front, a Sunni group with a strong religious bent.
To some extent, the American government did recognize a need to court moderate religious figures who could play roles in Iraq's future. Even before the 2003 invasion, American officials allied themselves with exiled clerics like Ayad Jamal Addin and Sheik Abdel Majid al-Khoei, a member of one of Iraq's most prominent Shiite families.
But the Americans seemed unaware of the complex and deadly rivalries among Iraq's religious factions. After being brought back to Iraq by the Americans in 2003, Mr. Khoei was stabbed to death in the Shiite holy city of Najaf by followers of Mr. Sadr. That killing led the American occupation authority to issue an arrest warrant for Mr. Sadr, which was dropped after he led two bloody uprisings in 2004 and became one of Iraq's most powerful figures.
Mr. Sadr's family has long been engaged in a rivalry with the Shiite religious establishment in Iraq, known as the Hawza. Under the rule of Saddam Hussein, Mr. Sadr's revered father, Ayatollah Muhammad Sadiq al-Sadr, was one of the few clerics to openly defy the dictator. He also expressed contempt for Ayatollah Sistani and other senior clerics, calling them the "Silent Hawza" for their complacent attitude in the face of tyranny. The young Sadr claimed his father's mantle after Mr. Hussein had the elder Sadr and his two eldest sons killed in 1999.
The militancy and growing power of Mr. Sadr and Mr. Hakim are upending the Shiite hierarchy, in which four grand clerics in Najaf are supposed to wield the most influence. When Mr. Sadr led his two anti-American uprisings in 2004, taking the city of Najaf hostage, Ayatollah Sistani initially watched helplessly from his home there.
The stridency of Mr. Sadr and Mr. Hakim has also contributed in pushing the older clerics to adopt a more aggressive tone toward Sunni militants, especially as the patience of the Shiite people wears thin in the face of relentless slaughter. After the shrine bombing on Wednesday, Ayatollah Sistani called on "believers" to defend religious sites if the government was unable to do so — exactly the same language that Mr. Sadr used in telling the Mahdi Army to defend places of worship.
The tensions between Mr. Sadr and Mr. Hakim have affected virtually every aspect of Iraqi society. Each man has staked out territory in the police and commando forces by swelling the ranks of those units with their militiamen. This month, Mr. Sadr played the role of kingmaker by throwing his support to Mr. Jaafari during a Shiite vote for the prime ministerial nominee, effectively blocking Mr. Hakim's candidate. Occasionally the rivalry explodes into violence, as it did last summer when Sadr militiamen stormed Supreme Council offices across the south.
Given all this, and amid the growing sectarian bloodshed, the voices of religious moderates like Ayatollah Sistani are increasingly falling on deaf ears. Shiite tribes "have put a lot of pressure on Sistani in the last year to go for revenge," said Mr. Hiltermann of the Crisis Group. "People are just not listening anymore in the face of these sick outrages."