JERUSALEM — U.S. Secretary of State Condoleezza Rice ended her fourth Middle East shuttle in four months without announcing the dramatic breakthrough in Israeli-Palestinian peace talks she had planned.

Rice had hoped to proclaim accelerated negotiations for the establishment of a Palestinian state. But Israeli Prime Minister Ehud Olmert quashed the idea, arguing that the Palestinians were unable to deliver on basic Israeli demands — like an end to Kassam rocket fire and the release of captured Israeli soldier Cpl. Gilad Shalit — let alone on a full-fledged peace deal.

Still, efforts to achieve an Israeli-Palestinian breakthrough will be stepped up.

As part of a compromise formula, Rice announced at a March 27 news conference in Jerusalem that Olmert and Palestinian President Mahmoud Abbas will meet every two weeks, but will not tackle core issues like final borders, Jerusalem and Palestinian refugees.

Instead they will focus on two parallel tracks: dealing with pressing problems on the ground such as security for Israelis and greater freedom of movement for Palestinians, and discussing what Rice calls a “political horizon” — that is, the general contours of the final peace deal Palestinians can look forward to without going into details on the core issues.

What this boils down to is that over the coming weeks Israelis and Palestinians will be discussing the first and last stages of the international peace “road map” simultaneously, in the hope that progress on either stage will redound on the other.

That is a major concession by Israel, which had been insisting that the Palestinians first carry out first-stage obligations, like ending violence, before advancing the process. The thinking now is that if the Palestinians know what kind of state the talks are leading to, they might be more confident about ending violence and terror.

Rice will join the bilateral talks at frequent intervals to help the parties “overcome obstacles” and better define the “political horizon.” She also hopes to add a wider Arab dimension to help the Israelis and Palestinians move forward.

Rice said the Arabs should offer Israel “a political horizon” like the one Israel is offering the Palestinians: that is, give a clearer idea of how Israel’s position in the region would be enhanced once the Palestinian problem is resolved.

Over and above the Israeli-Palestinian negotiating structure now in place, Rice and others in the international community are looking to build an Israeli-Arab superstructure that could energize the Israeli-Palestinian track and create conditions for a comprehensive Middle East peace.

One of the ideas being considered is an international conference of major players attended by the diplomatic Quartet (the United States, European Union, Russia and the United Nations) and the moderate Arab quartet (Saudi Arabia, Egypt, Jordan and the United Arab Emirates), along with Israel and the Palestinians. Olmert has indicated his willingness to participate.

The trouble with all this is that although Rice has been able to put a negotiating mechanism in place — no small thing in itself — she has little to show on substance.

The moderate Arab countries have made it clear that they will not move on normalization with Israel unless there is significant progress on the Palestinian track, and that is unlikely unless the intractable Palestinian refugee issue can be resolved or deferred.

Where Israel and the United States are hoping that the wider Israel-Arab arena will energize the Palestinian track, the Arabs are saying that it is the Palestinian track that must move first. In the past, such differences have been enough to create immutable deadlock.

What is new in the current equation is the intensity of the American commitment. Rice has apparently won the argument in the administration with the neo-cons over the possibility of movement toward an Israeli-Palestinian peace.

Israeli analysts conclude that unlike the neo-cons, she believes that such movement is possible and that it could strengthen the axis of moderate Arab states around U.S. leadership in the critical standoff with Iran. They fear Rice may be prepared to pay for closer ties with the Arab moderates in Israeli coin.

Moreover, the analysts say, even if this leads to friction with Israel, America’s wider interests in the region will not be harmed. On the contrary, public differences with Israel could actually enhance Washington’s regional standing.

Rice’s new initiative was made possible by two recent developments: the establishment of a Palestinian national unity government and the resuscitation of the 2002 Saudi-initiated Arab peace plan.

Palestinians argue that Abbas will be able to negotiate a fair deal with Israel and the unity government, with its wide political spectrum, will be able to deliver the Palestinian people.

The Saudi initiative, which offered Israel normalization in return for full withdrawal from Arab territory captured in 1967, raised anew the possibility of a comprehensive Middle East peace.

In her eagerness to improve U.S. standing in the region, Rice is now building on both these developments, at a cost of some friction with Israel, Israeli analysts say.

The key indicators over the coming weeks will be whether Shalit is released and whether a formula on Palestinian refugees acceptable to Israel can be found.

In weekend interviews with the Israeli media, Abbas argued that both these problems could be solved if the two sides would just sit down and talk. He said he was doing all he could to secure Shalit’s early release, and as for the refugees, he pointed out that the Arab peace plan talks about an “agreed solution,” implying that Israel could veto any mass return of refugees to Israel proper.

“But if we don’t sit down and talk, we won’t solve the problem,” Abbas warned in an interview with the Yediot Achronot daily.

Rice is taking a similar view. She is clearly hoping that if the parties talk seriously and often, something will give.

“Very often what happens in international politics is that you put in the hard work up front, and then there’s an opening — an opening that perhaps you didn’t expect at the time that you started,” Rice said at her Jerusalem conference.

“You don’t really know when it’s going to come, and all of a sudden you can move forward much more quickly because a lot of the ground work has been done.”