From a modest home in this holy city, Iraq's top Shiite cleric is projecting increasing political influence that has jeopardized Washington's plan for transferring power to Iraqis.

The rapid rise of the 75-year-old Grand Ayatollah Ali al-Husseini al-Sistani (search) as a dominant voice in politics reflects the emergence of the Shiite (search) majority after decades of suppression by a Sunni Arab minority.

The United States already has dropped one political plan for Iraq after al-Sistani's insistence that elected rather than appointed representatives draft the new constitution prompted the Americans to speed the timetable for handing over sovereignty and to delay the drafting of a new national charter.

U.S. officials now say a substitute formula announced Nov. 15 also may have to be modified to accommodate al-Sistani's demands that an interim legislature be elected, and not selected from regional caucuses as called for in the latest plan.

Iraq's U.S. administrator, L. Paul Bremer, and the current president of the Iraqi Governing Council, Adnan Pachachi (search), were to meet Monday in New York with U.N. Secretary-General Kofi Annan to discuss a broader U.N. role here and a way out of the impasse with al-Sistani.

The American plan sets a June 30 deadline for the formal end of the occupation and establishment of a sovereign Iraqi government. It also calls for legislators to be chosen in 18 regional caucuses, which Shiites fear could be manipulated to promote U.S.-favored candidates.

Supporters of the ayatollah, who was virtually banned from public appearances by Saddam Hussein, insist he is only trying to protect national interests at a crucial stage in Iraq's history.

The Iranian-born Al-Sistani, believed suffering from a heart condition, has not left his house on a dusty alley in this city, 100 miles south of Baghdad, in nearly a year and refuses to meet U.S. officials or grant media interviews.

His political pronouncements are few but they carry enormous weight and he has become a symbol of Shiite power, despite proclaiming that his spiritual calling takes precedence over politics.

Meanwhile, the Sunnis — who also dominated the nation's political establishment under former Ottoman and British colonial masters — are unable to find an effective and unified leadership to play a meaningful political role after the ouster of Saddam's Baathist regime.

"It is inevitable that after the Baath is gone, the clerics will step in to fill the vacuum," said Juan R. Cole, a University of Michigan expert on Iraqi Shiites.

Unlike followers of the mainstream Sunni sect, Shiites revere their top clerics as saints and look to them for guidance on everything from the mundane matters of everyday life to complicated theological issues.

While ruling out an Iranian-style theocracy, Cole and other experts suspect Iraq will end up with a government in which Islam provides the basis of legislation and clerics play a direct role in social issues.

This scenario already is taking shape, at least in part.

Al-Sistani uses the Internet to answer queries from his followers. His Web site contains his replies to questions ranging from the Shiite religious tax known as "khoms," or "fifth," rituals of the annual pilgrimage, or hajj, to Mecca in Saudi Arabia and even guidance on sexual relations between married couples.

Inside Najaf's Imam Ali mosque, Iraq's most sacred Shiite shrine, banners declaring absolute loyalty to al-Sistani are hoisted over the walls. Portrait posters of the silver-bearded cleric are plastered on many walls in the city and sold on the street.

Supporters say al-Sistani is revered by Shiites as far afield as Lebanon, Pakistan, India and Bahrain.

Reflecting the cultural and linguistic diversity of his followers, information on al-Sistani's Web site is available in five languages — Arabic, Urdu, French, Farsi and English.

Al-Sistani began his formal religious studies in Iran's holy city of Qom after he began learning the Quran by heart when he was 5. He moved to Najaf in 1952, where he became a "mujtahid," or a senior scholar knowledgeable enough to rule on religious issues, at the relatively young age of 31, according to an official biography.

His rise to prominence in the Shiite world outside Najaf began with the 1992 death of his mentor, the late Grand Ayatollah Abul-Qassim al-Khoei. Al-Khoei's opposition to attempts by Iran's Ayatollah Ruhollah Khomeini to dominate Iraq's Shiites and his resistance to Saddam's demands for a fatwa, or edict, in support of the 1980-1988 war against Iran left a strong impression on al-Sistani.

Experts believe the "quietest" approach of senior Shiite clerics like al-Khoei and al-Sistani was a necessity under Saddam's Baathist regime, which saw robed Shiites as Iranian agents and deported tens of thousands of Shiites to Iran.