As Marines step up preparations for military offensives on two major Iraqi cities, a number of Sunni Muslim leaders are forwarding a plan to establish the rule of law in those areas through peaceful means, with the promise of reducing the insurgency across a large swath of the country.

Some of the groups leading the bid have encouraged violent resistance in central, western and northern Iraq. The groups say they will withdraw their support for violence if Iraq's interim government can reassure Sunni leaders wary of national elections, which are scheduled for the end of January.

The Sunnis have proposed six measures, including a demand that U.S. forces remain confined to bases in the month before balloting. Such an ambitious demand, which some advocates acknowledge is not likely to be met and may be open to negotiation, represents a dramatic shift by Sunni groups opposed to the U.S. operation in Iraq.

Until now, groups such as the Association of Muslim Scholars, which supports the new proposal, had insisted that no election could be considered legitimate until Western troops left Iraq. The association has repeatedly threatened to call for an election boycott through the loudspeakers of Iraq's Sunni mosques, which the association represents.

"We took an initiative regarding the elections. It is being welcomed by the people on the boycott side," said Wamidh Nadhmi, a Baghdad University political science professor who is spokesman for the initiative. "They said that if such agreements could be met by the Americans, they could change to participation."

The U.S. Embassy in Baghdad offered no reaction to the proposal, which it received this week. A Western diplomat emphasized that any decision lay with Iraq's interim government.

In separate interviews, senior U.S. and Iraqi officials were privately skeptical of the overture and indicated it was unlikely to avert a military offensive on Fallujah and Ramadi, which commanders say could begin at any time.

"They don't seem to get it. The monopoly of power is over," said a senior Iraqi government official, referring to former President Saddam Hussein's Sunni-dominated government. "One wonders how representative these elements are of the mainstream Sunni population. They may represent nostalgia for the past, but for sure no realistic vision for the future."

Some former officials with experience in Iraq called the Sunni proposal a potential breakthrough that could avert not only an assault on Fallujah but also a violent aftermath, when insurgents might take the fight elsewhere.

"Most of what we've learned about insurgencies is that you don't defeat one through purely military means," said Larry Diamond, who served in the U.S.-led occupation authority. "When you try to do that, you may win the battle but lose the war. The insurgency in the Sunni heartland is now quite broad-based, and I don't think we're going to defeat the insurgency in this part of the country through purely military means. I think we're looking at a protracted insurgency which will get worse if we go through with elections" that many Sunnis boycott.

"These groups," Diamond said, "have to be given evidence that it's in their interests to participate in the electoral process."

U.N. Secretary General Kofi Annan, in a letter to President Bush disclosed Friday, warned that an assault on Fallujah "would be very disruptive of Iraq's political transition."

"Persuading elements who are currently alienated from, or skeptical about, the transition process to compete politically is key to creating a political and security context that will inspire confidence among all Iraqis," Annan wrote.

Iraqi and American officials also cite the impending election as a reason to take military action. Fallujah has been controlled by insurgents since April. They also move freely in Ramadi, the provincial capital, 30 miles to the west. In most of the rest of the country, voter registration began this week, and officials say the legitimacy of an ostensibly nationwide ballot will be undermined if residents of the Sunni Triangle area cannot take part.

Iraq's Sunni Arab minority, geographically concentrated in the country's midsection, was favored under Hussein. But Sunnis were markedly under-represented on the Governing Council put in place by the U.S.-led occupation and in the interim government that took power from the council in late June.

Elections could correct the imbalance, but many observers note that the country's majority Shiite Muslim population -- long disenfranchised and eager to claim elected office -- is better organized, larger, and pressing every advantage. On Thursday, the electoral commission announced that Iraqis who live overseas will be allowed to vote. The controversial decision is seen as benefiting Shiites who fled into exile under Hussein.

Nadhmi, the professor, emphasized that the groups behind the overture, who gathered under the umbrella of the Iraqi National Founding Conference, include Shiites and Christians. But the bulk of the conference represents Sunni interests. They include the Iraqi Nationalist Party, which has pan-Arab roots; the Democratic Reform Party, dominated by members of Hussein's Baath Party exiled to Syria; and the Association of Muslim Scholars, which claims to represent every Sunni mosque in Iraq and has frequently endorsed calls for resistance.

"This initiative is very significant," said an official involved in establishing the transitional government, who asked not to be identified because of the sensitivity of the issue. "They're no longer saying, 'We're not participating because the country is occupied.' They're saying, 'The government is not right. The only way we can make it right is by elections.'

"If you look at their demands, they're not impossible. They are things that can be discussed."

Several of the demands are grounded in skepticism about Iraq's newly minted election commission, a low-profile agency established by U.S. and U.N. officials. The Sunni group says it wants the panel reconstituted with prominent Iraqi judges "known for their honesty," and it wants the panel's work supervised by election monitors from other Arab and Islamic countries.

The group also wants the repeal of election regulations barring senior Baathists from standing for office, saying international norms call for bans only on people convicted of crimes. Ayad Allawi, the interim prime minister, has reversed some elements of the "de-Baathification" program put in place by L. Paul Bremer, the administrator of the U.S.-led occupation authority, but the bar on candidacy remains.

"There's a possibility of a Baathist slate," conceded Diamond, the former occupation official. "Now, these are nasty people. But I'd rather have them running peacefully in the election and winning a few seats in parliament than paying people to plant [roadside bombs] for our troops."

Most difficult for Iraqi and U.S. officials is the demand that American and other foreign forces remain outside major cities for the month of January. Insecurity is a profound problem across Iraq, and Iraqi police and other forces have not proven themselves capable of bringing certain areas under control.

The picture is further complicated by the presence of foreign fighters intent on carrying out violent strikes. Despite strains with Iraqi insurgents motivated by nationalism, Fallujah residents have said the foreign fighters continue to blend among the indigenous resistance. Negotiations between Allawi's government and Fallujah leaders broke down over the city's inability or refusal to eject the fighters.

One advocate of the new initiative said Iraqi Sunnis would persuade the foreigners to leave, though it may take time. He said attacks on U.S. and Iraqi forces would dissipate sooner if significant numbers of former Baathists feel they have a stake in the "new Iraq."

"Everyone agrees they are the spinal cord of the insurgency, and these groups have moral authority over them," said the official, who was formerly involved in Iraq.

Diamond acknowledged the proposal carried risks and may arrive too late to dissuade U.S. and Iraqi officials "who think it's time to go in and kick some butt."

But he added, "If there's a chance that this could be the beginning of political transformation that could change the situation on the ground, I think we've got to take it. Especially since many of the foreign fighters are said to have left Fallujah."

Sunni Muslims listen to a sermon during Friday prayers telling them to participate in upcoming elections. Many Sunni religious leaders had previously insisted that legitimate elections could not be held until the U.S. occupation ended.