THE Palestine Liberation Organization emerged this weekend from a fierce debate in its exiled parliament to cast itself on the mercy of its longtime foe, the United States.In a clear victory for PLO Chairman Yasser Arafat and moderates, the Palestine National Council (PNC) effectively committed the Palestinians to attending the planned Middle East peace conference. But it asked Washington to press Israel harder for a better deal out of the talks. With an overwhelming majority of delegates wanting to see Palestinians join the conference, their hope now is that Washington can save them from humiliating terms for participation. The PNC made it clear it was attaching no preconditions to Palestinian attendance, and PLO leaders stressed their flexibility. The PNC final declaration, approved Saturday, said merely that the success of "endeavors to convene the peace conference requires pursuing efforts with the other parties to realize" a set of six "bases," or demands. It asked the PLO executive committee to "continue the current efforts to provide the best conditions" for Palestinian participation in the talks, and to report to the 80-member PLO central council for a final decision. The aim, explained PLO Information Department chief Jamil Hillal, was to "emphasize what the PLO would like to happen ... without necessarily saying that unless all the points are fulfilled, we will not take part." The key points are that the conference should be convened on the basis of United Nations Resolutions 242 and 338, which call for a full Israeli withdrawal from occupied territories; that Arab East Jerusalem be considered part of the occupied territories; that Jewish settlement end before talks begin; and that the PLO has the right to form the Palestinian delegation. Now, PNC members say, it is up to the US to use its leverage with Israel to enforce these demands and make it possible for Palestinians to attend the conference. "We have to wait and see what Bush and Baker will do," said Assad Abdul Rahman, an independent member of the PLO central council. "Everything is in the Americans' court." "Now it is up to the United States to give some new elements encouraging the Palestinian people to engage in this process," added Daoud Talhami, a leader of the Democratic Front for the Liberation of Palestine (DFLP). Palestinian leaders appear to be putting unusual trust in Washington to work on their behalf, arguing that the US position on most of the key points is closer to their stand than to Israel's. The United States, they point out, agrees that UN Resolutions 242 and 338 imply a land-for-peace solution and require Israeli withdrawal from occupied territories. Washington has also condemned Jewish settlement in the territories as illegal and regards East Jerusalem as occupied territory, despite Israeli insistence that since annexation in 1981 it is a part of the Jewish state. Talking to reporters on Saturday, Mr. Arafat drew special comfort from President Bush's reference last week to "the Palestinian people," rather than "the Palestinians," which the PLO leader saw as implying "national rights" such as self-determination. "The best guarantee [for Palestinians] is that the United States remain involved and committed to the peace process," said Arafat aide Bassam Abu Sharif during the meeting. Though radical groups such as George Habash's Popular Front for the Liberation of Palestine were unhappy with the PNC outcome, most delegates, particularly the more pragmatic figures around Arafat, expressed themselves delighted with the results. Having gone into the PNC with its back against the wall, faced with a choice between surrender and inviting international condemnation by boycotting the conference, the PLO "avoided catastrophe," said delegate Faisal Hurani. "We did not give others a reason to trap us." Although a final decision on whether terms of participation are satisfactory has been left to the central council, Arafat advisors seemed happy with the margin for maneuver he has been left. If the PNC's "bases" are to be fulfilled, however, US Secretary of State James Baker III still has a huge task ahead of him to persuade the Israelis to cooperate. One of the most irksome issues - and the PLO demand that comes closest to a precondition - is the PNC call for "an end to settlement of the occupied territories, including Holy Jerusalem, as an indispensable necessity to start the peace process." Although Arafat refused to be drawn by reporters into saying Palestinians would not attend the conference without a prior freeze on settlements, one of his top aides, Nabil Shaath, said later he thought "without that it would be very, very difficult" for the central council to approve participation. The exact nature of the PLO's role in the conference is also still thorny, given Israel's refusal to negotiate with PLO representatives and the PLO's insistence on its right "to form the Palestinian delegation" and "to ensure the PLO as the reference authority" for any Palestinian delegates. The Palestinians' strategy, it appears, is to insinuate the PLO into the process step by step, drawing ever closer links between the organization and Palestinian figures in the territories who might be members of the delegation. "We already have an indirect role, almost a clear cut and implicit role," says Mr. Abdul Rahman. "We would like to improve on that to the point where the PLO will publicly and directly participate, and hope that by then [Israeli Prime Minister] Yitzhak Shamir will not be in a position to say no." The PNC central council is expected to wait until the last moment before the conference is convened before announcing whether or not Palestinians will attend.