All week, events in Egypt had churned so rapidly it was hard to keep up, even for a U.S. secretary of state who travels with a phalanx of BlackBerry-wielding aides. When Hillary Rodham Clinton departed Washington late Friday for a conference in Germany, the Egyptian capital was peaceful and the government appeared to be moving toward negotiations with protesters. By the time the plane landed Saturday, the fragile progress had stalled.

The head-spinning pace of change prompted an acknowledgment by Clinton about the limits of the United States' ability to influence to shape of the government that will come after President Hosni Mubarak.

"Those of us who are trying to make helpful offers of assistance and suggestions for how to proceed are still, at the end, on the outside looking in," a weary Clinton told a European security conference Saturday.

Clinton's comment summed up the Obama administration's quandary as Egypt's unprecedented protest movement prepared to enter its third week. After days of efforts to nudge Mubarak off the stage, if not necessarily out the door, the White House was compelled to shift its approach last week after both the Egyptian president and his top aides made clear that he intends to stay.

Mubarak's defiance was followed by a convulsion of violence in Cairo, then a period of hopeful calm as progress toward negotiations appeared to gain momentum, then renewed uncertainty as that effort faltered while Clinton flew. With the Muslim Brotherhood's agreement Sunday to enter talks with Mubarak's newly appointed Vice President Omar Suleiman, optimism has reasserted itself.

While acknowledging that violence could erupt again, U.S. officials and Middle East experts credited the administration with establishing useful parameters - in essence, that the government must avoid violence and that Suleiman and the opposition must talk, and quickly - that have helped to prevent, for now, the country's slide into anarchy.

"We ought to be elated that they are, in fact, sitting down. That the army has restrained itself. That some semblance of order, even as there are protests, is being restored to the streets," Senate Foreign Relations Committee Chairman John F. Kerry (D-Mass.) said Sunday on NBC's "Meet the Press."

Once it was clear they were stuck with Mubarak, administration officials refocused their efforts on encouraging Egyptian government officials and opposition groups to begin work on a blueprint for a transition to a new government. Here, too, U.S. plans collided with the agendas of Egypt's fragmented opposition groups, some of whom balked at participating in any negotiations while Mubarak remained in power.

Administration officials, in interviews, described a diplomatic blitz that targeted scores of Egyptian government and military officials, urging an immediate halt to violent attacks against protesters by pro-Mubarak demonstrators. U.S. officials, with backing from allies in the region, also pushed to encourage opposition groups to agree to negotiations on power-sharing, even as Mubarak continued to cling to the presidency.

"It's not a great victory, but it's far better than where we were two days ago," said a senior administration official who helped lead the effort. Like others interviewed for this story, the official spoke on the condition of anonymity to discuss internal administration thinking.

The strategy takes shape

The Obama administration had been steadily ratcheting up the pressure on the Mubarak government since massive anti-government demonstrations began nearly two weeks ago. On Jan. 30, Obama convened a meeting of his national security team to hash out a strategy that balanced U.S. support for democratic reform with the need to preserve stability in a country that has been a key U.S. ally for decades. The administration drew up a list of short- and long-term policy goals. They hinged on channeling the country's growing street protests into a political process that would be accepted across Egypt's political spectrum and would lead to elections for new leaders.

The following day, Clinton appeared on five Sunday talk shows touting a catchphrase that she had coined: The United States would seek an "orderly transition" in Egypt that would lead to democratic reforms without destabilizing the country. Clinton and other administration officials said repeatedly that it was up to Egyptians to decide whether and when Mubarak would step down. But the White House's preference was implicit.

"Clearly, this would be easier if he chose to leave," said a second U.S. official who participated in the internal discussions.

But U.S anxiety over the trajectory of Egypt's crisis intensified in the wake of Mubarak's televised speech Tuesday, in which he vowed to remain in office until elections scheduled for September. While Mubarak ruled out running for office again, his refusal to leave immediately infuriated anti-government protesters and seemed to presage the two-day spasm of violence that followed.

Beginning Wednesday morning, thousands of Mubarak supporters poured into central Cairo and other major Egyptian cities and pelted protesters with rocks, sticks and fists. Security forces meanwhile launched a campaign of harassment against journalists and human rights activists, detaining dozens of them. State Department workers on Wednesday clustered around television sets watching surreal scenes of whip-wielding Mubarak supporters charging through crowds of anti-government protesters on horses and camels.

That morning, Clinton phoned Suleiman for what aides described as a frank 15-minute phone call.

"She expressed the very strong view that the violence we were seeing had to stop and security forces had a responsibility to protect peaceful protesters," said a U.S. official briefed on the exchange.

Suleiman "responded affirmatively," the official said. And yet, over the following 24 hours, more violence followed.

'Play of the day'

Already, the White House had settled into a pattern of daily meetings to deal with the rapidly evolving crisis. Each morning at 8:30 a.m., deputy national security adviser Denis McDonough convened a deputies meeting in the White House Situation Room to establish the "play of the day" - in West Wing jargon, a plan for responding to the day's unfolding events. Afterward, Obama would receive his daily intelligence briefing - dominated increasingly by news and assessments from Egypt - and the president would strategize with top aides on what steps to take that day to prevent the turbulence from spiraling out of control.

Obama, along with Clinton, Vice President Biden and Defense Secretary Robert M. Gates, had already been making daily calls to Egyptian leaders to sound now-familiar themes. But as the violence worsened on Wednesday, the pace of the diplomatic effort stepped up dramatically.

"We conveyed the message at every level of government that a crackdown does not get to a political process," the second administration official said.

Meanwhile, other State Department officials - including William J. Burns, undersecretary for political affairs; Jeffrey D. Feltman, assistant secretary for Near East affairs; and Margaret Scobey, U.S. ambassador to Egypt - were opening lines to a variety of other Egyptian political figures and opposition leaders while also reaching out to nervous allies in the region. Among those receiving multiple calls were Arab League President Amr Moussa and Mohamed ElBaradei, the former U.N. nuclear official and now a representative for several of the opposition groups involved in daily protests in Cairo's Tahrir Square.

"The administration had been effective in maintaining a public message, but now they strengthened their words and put more teeth into it," said Joel Rubin, a former Egypt Desk officer at the State Department and now chief operating officer for the National Security Network, a Washington think tank. "It became an all-hands-on-deck moment. They were applying pressure at every pressure point they had."

The strategy shifts

While Egyptian officials never acknowledged any involvement in the assaults on pro-democracy protesters, the attacks ended suddenly late Thursday. By Friday morning, army troops had moved into place to separate the opposing groups of demonstrators, and the detention of journalists and human rights activists all but stopped.

Administration officials attributed the Egyptian army's restraint in part to Gates's calls - four in all - to Field Marshal Mohammed Hussein Tantawi, head of the military. But while the violence ebbed, army officials refused to budge in their support for Mubarak, whose continuation in office has prompted some key opposition players to reject negotiations until he is gone.

The administration's essential Egypt strategy began to shift to focus less on Mubarak's departure, allowing that Egyptians "could get through this door another way," in the words of another senior administration official. The process, the official said, would include all key political parties and would probably involve discussions over the constitution and institutions that would have to be changed to ensure democratic elections.

"This is difficult because many of the opposition figures have made Mubarak's departure a precondition for talks," the official said. "The challenge is how do we get from this dangerous situation - daily protests, daily demonstrations - to a process."

Implicit in the White House's internal discussions was an acknowledgment that the administration could set parameters and offer advice, the official said, but ultimately had little influence over developments on the ground.

"We're dealing with a very dynamic situation that we do not control," the official said.

Staff writers Mary Beth Sheridan, traveling with Clinton, and Karen DeYoung in Washington contributed to this report.