AMMAN, JORDAN — IF the Palestine Liberation Organization accedes to United States and Israeli terms for Palestinian participation in the planned Middle East peace conference it may signal the beginning of the organization's demise.The US has stipulated - in order to overcome Israeli refusal to talk to the organization - that Palestinians should come to the conference as part of a joint delegation with Jordan. The delegates cannot be PLO members and must be drawn from the Israeli-occupied West Bank and Gaza Strip. But by accepting these conditions the PLO is effectively relinquishing its raison dtre: the political representation of Palestinians. To Western and even Arab observers, Palestinian participation at the conference is a procedural matter that should not be allowed to obstruct the opportunity to achieve peace. But for the PLO, and its Palestinian supporters, sacrificing the organization may mean jeopardizing their right to voice their aspirations. "The PLO is the expression of Palestinian nationalism. Therefore by insisting on excluding it from the conference, we fear that the Americans are trying to deprive the Palestinians [of] the right to ... demand their national rights," says Jamil Hilal, chief of the PLO information department in Tunis. Palestinian leaders from the occupied territories, in negotiations with US Secretary of State James Baker III, have been seeking US recognition of the Palestinian people's right to self-determination. But the US negotiators have made it clear, according to Palestinian leaders, that Washington is not ready to recognize explicitly that the Palestinians are seeking an independent state. According to Israeli Foreign Minister David Levy, Washington has assured Israel that it will not endorse the establishment of a Palestinian state in the West Bank and Gaza Strip. The PLO has been resisting what it views as attempts to end its role by insisting that it name the Palestinian negotiators and that self-determination be on the agenda. It also wants a way to control the Palestinian delegation during the conference and to provide independence for the Palestinian side of a joint delegation. But even if the US were to accept such terms, the PLO still risks losing control over the process once negotiations begin. These concerns have sparked an unprecedented debate within the PLO and among the Palestinians in the diaspora and inside the occupied territories. There are Palestinians, including PLO officials, who admit that they are demoralized by the regional political and military situation and argue that the organization should give Palestinians a chance to try to end their suffering under Israeli occupation - even if that means the end of the PLO and compromising Palestinian aspirations toward self-determination. And there are those who reject any involvement in the peace process, saying that the PLO has failed in its mission, but should not sacrifice Palestinian rights in order to attend the conference. But a third line of thinking, which seems to be prevailing so far, is that the PLO should accept an indirect role provided it makes sure that it remains the responsible party for the Palestinian delegation. But even these advocates concede it might mean the end of the PLO in its current form. "It is an end of an era in the Palestinian struggle, it might be the end of the current form of the PLO, but certainly not the end of the Palestinian movement," a senior PLO official said. Some of the movement's founders warn that ending role of the PLO will threaten stability in the region. "The PLO plays a very important role in controlling and directing Palestinians everywhere. If the PLO's role is ended then frustrated and dispossessed Palestinian will be forced to resort to other violent means - in that case no government or party can control Palestinian extremism," warns Intissar Wazir, the widow of the assassinated Palestinian leader Khalil al-Wazir Abu Jihad.