Powell, in repeated appearances Thursday, said that the U.S. had not abandoned its role as an honest broker for peace. He insisted that the Sharon plan offered "an opportunity, for the first time in 37 years, to see settlements being emptied. And this is the beginning of a process. It is not the end of a process."
Powell noted that Sharon had committed himself to withdrawing Israeli troops from the Gaza Strip and removing all settlements in Gaza and four settlements in the West Bank.
He argued that Bush, in allowing Israel to keep other major West Bank settlements and resettle Palestinian refugees from Israel into a new Palestinian state, was "merely commenting on the reality, and it's a reality that people have known for years and years and years."
Repeating a long-held U.S. position, Powell pledged that the final settlement was for Israelis and Palestinians to work out, not for the United States to dictate.
Other officials noted that the deal included an unequivocal commitment from Sharon to the U.S.-backed peace initiative, or "road map," for side-by-side Israeli and Palestinian states, as well as a reaffirmation that a fence Israel is building does not represent a permanent border.
"It's going to certainly roil the waters and create more problems for the credibility of the United States in the region," said Edward S. Walker Jr., president of the Middle East Institute and a former ambassador to Egypt, Israel and the United Arab Emirates.
"In [the Arab] view, we have tilted so far to Sharon that we can't be a mediator anymore. So it's going to make it very difficult to move the road map process along, even if we want to -- which I'm not sure we do," Walker said, reflecting widely held skepticism that Bush would impose a solution on Sharon.
Powell on Thursday spoke by phone with Mubarak, Egyptian Foreign Minister Ahmed Maher, Palestinian Authority Prime Minister Ahmed Korei and King Abdullah.
On Wednesday, Mubarak had warned Israel against imposing its "disengagement" plan instead of negotiating with the Palestinians.
Walker said he doubted that Mubarak had been informed of details of the U.S. deal during his visit with Bush on Monday, "because he wouldn't have stood stolidly like that" next to the president in Texas in apparent support of what he understood to be Bush's Mideast agenda.
Egyptian diplomatic officials, still in Texas, did not return telephone calls for comment.
Some Arabs accused Bush of campaign-season pandering to Jewish voters.
"President Bush continues to reconfigure international law to suit his presidential campaign needs, and this is very dangerous," said George Jabbour, a Syrian lawmaker.
Lebanese President Lahoud in a statement called Bush's decision "illegitimate" and urged Arab leaders to call for an emergency session in the United Nations to oppose the newly articulated U.S. policy.
Efron reported from Washington and Stack from Cairo. Times staff writer Paul Richter in Washington contributed to this report.