This article was reported by Mark Mazzetti, Helene Cooper and Carlotta Gall, and written by Mr. Mazzetti.

WASHINGTON, Aug. 15 — The Bush administration, struggling to find a way to keep Gen. Pervez Musharraf in power amid a deepening political crisis in Pakistan, is quietly prodding him to share authority with a longtime rival as a way of broadening his base, according to American and Pakistani officials.

General Musharraf, an important ally since the Sept. 11, 2001, attacks, has lost so much domestic support in recent months that American officials have gotten behind the idea that an alliance with Benazir Bhutto, a former prime minister, would be his best chance of remaining president.

The two met in an unannounced session in Abu Dhabi on July 27, but neither has publicly admitted to the meeting. Since then, many in Pakistan have heard the rumors and voiced their doubts about the workability and political wisdom of such a deal, and American officials concede that the proposed power-sharing could come with problems as well as benefits.

But after weeks of unrest in Pakistan, the American officials say a power-sharing agreement that might install Ms. Bhutto as prime minister could help defuse a confrontation in which General Musharraf has already flirted with invoking emergency powers. Administration officials have said they fear that General Musharraf could eventually be toppled and replaced by a leader who might be less reliable as a guardian of Pakistan’s nuclear arsenal and as an ally against terrorism.

Even if General Musharraf were to insist on remaining as the country’s military leader, American officials say that sharing power could bring a more democratic spirit to Pakistan, which has been a quasi-military dictatorship since 1999, when General Musharraf seized power and ousted Ms. Bhutto’s successor, Nawaz Sharif.

Even in supporting a power-sharing agreement, the American officials say they worried that any diminution of General Musharraf’s power could only complicate American counterterrorism efforts at a time when Al Qaeda is believed to be rebuilding in Pakistan’s tribal areas. They also say that Ms. Bhutto’s return could fuel Pakistani nationalism and kindle new calls for Pakistan to distance itself from Washington.

Ms. Bhutto has been holding talks in recent weeks with senior Bush administration officials, including Zalmay Khalilzad, the United States ambassador to the United Nations, with whom she met privately late last week. Administration officials have taken pains not to endorse a power-sharing agreement publicly, so as not to seem as if the United States is trying to influence Pakistani politics.

But Secretary of State Condoleezza Rice did discuss the idea of a power-sharing arrangement when she called General Musharraf last week at 2 a.m. in Pakistan to warn him not to declare emergency powers, American and Pakistani officials said.

Ms. Bhutto and General Musharraf have a personal history going back many years. He was her chief of military operations when she was prime minister, yet he has said repeatedly that she would not be allowed to return before the coming elections. In fact, one of the biggest obstacles to any possible deal is whether Ms. Bhutto would demand that General Musharraf relinquish his post as army chief of staff before agreeing to a power-sharing deal. Ms. Bhutto has said in the past that she would demand this, but there have been suggestions in Pakistan in recent days that in order to salvage a deal, she may be willing to concede that point.

Several Bush administration officials agreed to talk about the American role in the discussions but refused to speak for the record because of the delicacy of the talks.

American officials say that the complexity of Pakistani politics makes it difficult to predict what shape a political deal could take. But a first step could be a decision by General Musharraf to allow open parliamentary elections next month, because Ms. Bhutto’s party now appears poised to win the largest share of the vote.

A victory by her party could pave the way for Ms. Bhutto to become prime minister, but she would probably need General Musharraf’s support to overcome further obstacles, including a law prohibiting former prime ministers from returning to that office. In turn, Ms. Bhutto’s support could be crucial to helping General Musharraf to victory in subsequent presidential elections that would allow him to stay in his current job.

Both leaders have faced a backlash within their parties as they explained the details to members. Members of the governing party, the Pakistan Muslim League, which backs General Musharraf, are furious at the possibility that, after attacking Ms. Bhutto for nearly eight years, the general is considering dropping court actions against her and offer her a share in power.

In an interview with The New York Times on Monday, Ms. Bhutto said that she was aware that an alliance with the now-weakened General Musharraf could hurt her politically.

“We want to avoid a situation where we are seen as bailing out an unpopular military dictatorship,” said Ms. Bhutto, who has been living in London and Dubai. She said the pace of the talks between General Musharraf and her Pakistan People’s Party was too slow, with him making promises that he has not kept.

“When we are doing this for a level playing field, when we’re doing this for a higher cause, which is the restoration of the people’s right to elect a government of their choice, that should translate into tangible measures,” Ms. Bhutto said. “And if it doesn’t translate into tangible measures, then it can be misinterpreted by the people at large.”

The daughter of a Pakistani prime minister who was executed by the military, Ms. Bhutto captivated the Muslim world when she became the first woman to serve as prime minister of an Islamic country. Her government was dismissed in 1996 amid accusations of corruption, and she has lived in exile since 1999 to avoid prosecution, although she denies wrongdoing.

State Department officials have told General Musharraf for months that he needed to broaden his political base and become less beholden to the Islamic groups that he has courted to shore up his power in the western part of the country. Asked about American support for a power-sharing deal, Sean McCormack, the State Department spokesman, said on Tuesday: “We have met with all parties, and have expressed our support for open and fair elections. We have encouraged the parties to strengthen the moderate center of Pakistani politics in order to better deal with the problems of extremism.”

Teresita C. Schaffer, a Pakistan expert at the Center for Strategic and International Studies in Washington, said that American officials saw a deal between General Musharraf and Ms. Bhutto “as a potential lifeline and one that would get him less deeply involved with the religious parties.”

Ms. Schaffer said she was skeptical that any alliance between the political heavyweights was manageable over the long term. In Pakistan, the general view is that General Musharraf needs the deal to stay in power, that Ms. Bhutto needs it to quash corruption cases against her in the international courts and that there is nothing in it for the people, said Talat Massood, a retired general and political analyst.

The Bush administration has had its own stormy relationship with General Musharraf. He sided with the United States against the Taliban after the Sept. 11 attacks, and has continued to provide what American intelligence officials say has been crucial support to counterterrorism efforts. But American officials have also become frustrated at what they see as passivity in efforts to root out Qaeda operatives in Pakistan.