BERLIN, Feb. 20 -- Over Christmas vacation, Secretary of State Condoleezza Rice took home a three-foot stack of reports written by the State Department historian on previous efforts by the United States to forge Middle East peace. Rice had read memoirs by her predecessors, but as she embarked on her own effort to help end the Israeli-Palestinian conflict, she decided she needed to study a day-by-day diplomatic narrative of what had gone wrong in the past.

Her conclusion: A diplomat needs to quietly build support behind the scenes in informal talks between the Israelis and Palestinians, seeking the right combination of leverage and circumstance to make an impact. In her mind, Rice and her aides say, the moment is now.

But the lackluster outcome of the Israeli-Palestinian summit brokered by Rice in Jerusalem on Monday suggests her optimism may be misplaced. Diplomats and Middle East experts applaud her willingness to invest her prestige in trying to solve an intractable problem, but some wonder whether her efforts are six years too late.

Rice is pushing the Israelis and Palestinians to sketch the contours of a Palestinian state, much as President Bill Clinton did before he left office. But diplomats say the prospects have dimmed with years of violence, weak leadership in both camps and the rise of the militant group Hamas, which is dedicated to Israel's destruction and won Palestinian legislative elections last year.

Palestinian Authority President Mahmoud Abbas on Tuesday described the summit as "tense and difficult," while the Israeli government ruled out discussions on the diplomatic endgame if Abbas goes through with plans to form a unity government with Hamas.

Rice -- who arrived here Tuesday night for talks with European officials after meeting earlier in the day with Arab diplomats and security chiefs in Amman, Jordan -- insists that the conditions have never been better for peace.

This confidence reflects her central role in developing and implementing U.S. policy toward the conflict for the past six years. "I think on paper there was a lot that was close" in 2000, Rice said last month. "But the underlying circumstances, I think, those conditions are better now."

The late Palestinian leader Yasser Arafat was never going to accept a peace deal, Rice argues, but he has been replaced by Abbas. She adds that the Likud Party was not going to support Clinton's proposals, but now much of the Israeli right accepts the idea of a Palestinian state after a Likud-led government, under Prime Minister Ariel Sharon, took the dramatic step of withdrawing from the Gaza Strip. "The breadth of the Israeli political system that is actually united behind a two-state solution is very different than in 2000," Rice said.

Rice's slant on the Middle East has been shaped in part by Israelis, first by Sharon and more recently by Foreign Minister Tzipi Livni, U.S. officials say.

Rice, for instance, adopted the phrase "political horizon" from Livni, which is intended to illustrate the endgame discussions, though it is not a new concept; then-Secretary of State Colin L. Powell used it in 2002. Rice's division of the region into "moderate" elements (Israel, Abbas, Egypt, Jordan and Saudi Arabia) and "extremist" forces (Iran, Syria, Hezbollah, Hamas) was also first articulated by Livni a few weeks before it became part of Rice's rhetoric.

Arabs and Europeans chafe at such clear-cut distinctions. "The Middle East is the Middle East," said Egyptian Foreign Minister Ahmed Aboul Gheit. "You have different trends, and you have different interests" that vary from day to day.

Aboul Gheit's view would explain why Abbas, supposedly a member of Rice's moderate camp, would join with the extremists. Abbas said the power-sharing arrangement is intended to stop Palestinian factional violence that has killed scores of people in recent months.

As national security adviser in President Bush's first term, Rice -- not Powell -- generally had control of Israeli-Palestinian policy because of a largely unpublicized back channel with Sharon's chief of staff, Dov Weisglass, according to U.S. and Israeli officials.

The most sensitive issues in the U.S.-Israeli relationship were handled through the Rice-Weisglass partnership. In a tense meeting with Weisglass in September 2002, Rice demanded that Sharon abandon an assault on Arafat's compound, U.S. and Israeli officials say. Rice, through the Weisglass channel, also encouraged in 2003 the development of Israel's plan to withdraw from Gaza -- in part to thwart European demands to push the two sides to begin final negotiations on a peace deal because the plan known as the "road map" was faltering.

Early in her tenure as secretary of state, Rice encouraged the Palestinians to hold legislative elections, even if Hamas participated, despite deep misgivings by Israeli officials. U.S. officials had assumed that Abbas's Fatah party would win, but Hamas unexpectedly prevailed. Rice then decided to push international donors to cut off all but humanitarian aid to the Palestinian government until Hamas renounced violence, accepted Israel and agreed to abide by previous Palestinian accords with Israel.

Although the Hamas victory halted peace efforts, Rice now says the election led to good because it forced the militant group to confront the challenges of governing. But U.S. officials concede that they were surprised when Abbas, with Saudi prodding, reached the unity accord with Hamas.

"She has a personal commitment to be involved now," said former Middle East envoy Dennis Ross. "But the nature of what she is involved in is in greater flux."

Rice's push follows a succession of administration initiatives that quickly faded, including a security plan by then-CIA chief George J. Tenet in 2001, the appointment of special envoy Anthony C. Zinni in 2002 and Bush's inauguration of the road map plan at a 2003 summit in Aqaba, Jordan. Within months, all were largely abandoned.

In one irony, the United States in 2003 had pushed for the creation of a powerful prime minister because it wanted a way to sidestep then-President Arafat; now, the administration wants to bolster the Abbas presidency as a way of undercutting the Hamas prime minister.

The administration has intervened in the Palestinian factional struggle, funneling money to bolster Fatah's image before the elections and now pushing a plan to train and supply security forces loyal to Abbas.

One Rice aide conceded that there is "diplomatic risk" to Rice forging ahead, but European officials are thrilled that she is now trying ideas they have long urged. A senior European official said Tuesday that just the fact that Rice did not cancel the meeting in the face of Israeli resistance was a signal, because the administration has had a pattern of halting peace efforts at the first sign of trouble. "To us, that is proof the United States is really engaged," he said, speaking on condition of anonymity.