BAGHDAD, Iraq — With three months left before a landmark election, a group of hard-line Sunni Muslim clerics may hold the key to Iraq's future.

The Association of Muslim Scholars, created only 18 months ago but now the most influential representative of Iraq's Sunni Arabs, is threatening to boycott the January balloting if U.S. and Iraqi troops storm the Sunni insurgent stronghold of Fallujah.

A large-scale boycott by the powerful Sunni Arabs — who make up 15 percent to 20 percent of Iraq's nearly 26 million people and are spearheading an increasingly vicious insurgency — would be disastrous for the vote's credibility and may push Iraq into even deeper disarray.

The association, which boasts an active membership of 3,000 clerics nationwide, has hardened its stance against the U.S. presence in Iraq recently as U.S. warplanes stage almost daily raids against suspected militant safe houses in Fallujah.

Sheik Abdul-Salam al-Kobeisi, a senior association official, said the group would call for a boycott if it determines the vote would prolong the American presence in the war-torn country.

"When we do, we will reject the elections, issue an edict declaring it illegitimate and not accept its results," he told The Associated Press. "We are capable of doing this, both in the so-called Sunni triangle and beyond."

The interim Iraqi government and its U.S. backers see the vote as a crucial step toward democratic rule in Iraq. It also is a major plank in Washington's exit strategy from Iraq, where it maintains about 140,000 troops.

In the election, which is supposed to be held by Jan. 31, Iraqis will select a 275-member assembly whose main task will be to draft a constitution. If adopted, it will be the foundation for a second election to be held by Dec. 15, 2005.

The Sunni association, which is suspected of maintaining links with some insurgent groups, has long been a staunch critic of the American presence in Iraq and of the U.S.-backed interim government of Prime Minister Ayad Allawi.

It has, however, been careful not to publicly condone armed resistance against American or Iraqi forces. Although no boycott call has been issued, al-Kobeisi hinted Saturday that the decision to oppose the ballot has already been made.

"Certainly, we have washed our hands of this election," he told AP. "Frankly, the association believes the election is a ploy to allow the Americans to stay."

A boycott call by the clerics would have resonance among Iraq's Sunni Arabs, who are angry and frustrated over the loss of power they enjoyed under Saddam Hussein. Many Sunnis fear domination by the long-oppressed Shiite majority.

Some Iraqi experts question whether a Sunni boycott would be universal. Nazim al-Jassour, a political scientist from Baghdad University, noted that some Shiite-led political parties, like Allawi's Iraq National Accord, have many secular Sunni members.