Why US suddenly lost its appetite for Saudi peace plan

Ominous and sharp rumblings from Israel have made the Reagan administration's public interest in the Saudi Arabian peace plan for the Middle East short-lived. Right after the US Senate vote on the AWACS deal for Saudi Arabia, both President Reagan and the State Department spoke positively about the peace plan.

Now, less than two weeks later, Mr. Reagan is silent about it. The State Department is pouring cold water on it and has even fired a few shots at Britain in support of Israel's barrage against Britain for its backing of the Saudi blueprint.

What has brought about the US change of course?

Recognition that an angry and desperate Israel, alarmed at what is seen as a US tilt toward Saudi Arabia, might resort to action in one or more of three areas that could put at risk the whole Middle East peace process. The three areas are:

* Completion of the Israeli withdrawal from the occupied Egyptian Sinai, due by April 25.

* The tenuous cease-fire in southern Lebanon.

* The deployment of European contingents alongside US units in the international peacekeeping force to be deployed on the Egyptian-Israeli border in Sinai once Israeli evacuation is completed in April.

Israeli Prime Minister Menachem Begin has summed up his objection to the Saudi plan tersely. He has called it ''a formula for Israel's liquidation.'' Further, he has made it clear that he will spare no effort to discredit the plan , to dissuade the European Community from its interest in it and to nip in the bud any inclination on the part of the US see it as a positive development.

On this, Mr. Begin has the support of the opposition Labor Party in the Israeli parliament. A joint parliamentary delegation is to visit both the US and Europe to put Israel's case and attempt to reverse any tilt toward the Saudis.

No Western government, not even the British now under such withering propaganda fire from the Israelis, has supported the Saudi plan in its entirety. But suggestions have been made at official level in the West that parts of the Saudi plan could be picked up as a basis for negotiation on the sensitive Palestine issue, should the Camp David formula prove inadequate to deal with it.

The Israeli response to this is to hint that if the Camp David framework is abandoned on the Palestine issue, Israel might feel justified in abandoning the same framework for its scheduled April withdrawal from the last segment of occupied Sinai.

That would be an almost intolerable setback for Egypt's President Hosni Mubarak. He is counting on having no hitches to prevent him from saying to his critics in April that Camp David and the peace treaty with Israel have cleared the last Israeli occupier from Egyptian territory after 14 years.

The Reagan administration has a vested interest in Mr. Mubarak's being able to make this claim next spring. And this could help explain its backtracking on the Saudi plan.

When it comes to a possible resumption of hostilities in south Lebanon, Israeli Defense Minister Ariel Sharon has reportedly told US Ambassador to Israel Samuel Lewis that the Reagan administration should not be surprised at developments in the near future.

Four months ago, US special envoy Philip Habib, with Saudi help, managed to negotiate a cease-fire in rapidly escalating hostilities between Israel and the Palestine Liberation Organization (PLO) in south Lebanon.

Last week, Mr. Sharon toured the Israel-backed Christian enclaves in south Lebanon under the control of the maverick Lebanese Maj. Saad Haddad. Mr. Sharon later spoke of PLO violations of the cease-fire and said Israel was considering a response.

The on-again off-again retirement of Major Haddad at the weekend was doubtless intended in some way to attract US (and other) attention to the possibility of fresh trouble in Lebanon. And if Mr. Begin wanted any pretext to stir the pot beyond alleged PLO cease-fire violations, he could point to the Syrian surface-to-air missiles still deployed in Lebanon. He has always said Israel would take these out by military means if the US failed to secure their withdrawal by negotiation.

Last month, when French President Frannois Mitterrand took an initiative that opened the way for the European Community to join US peacekeeping troops in Sinai, the US and Israel welcomed the move. The original intention, under Camp David, was that the UN should provide the peacekeeping force.

But the Soviet Union, hostile to Camp David, made it clear it would veto any UN move to police implementation of the agreement. As a result, it seemed that the US would have to do the Sinai policing job on its own - something it would have preferred to avoid. Hence last month's satisfaction when the Europeans indicated a willingness to join in.

Now that has gone sour, with Britain getting most of the blame for this turn. The Europeans, with Britain perhaps the most vocal, have dropped hints that their willingness to support Camp David decisions in Sinai will make it easier for them to advocate going outside Camp David for a Palestine settlement.

To the Israelis, that means the thin end of the wedge for forcing the Saudi plan on them. So Israel is saying it reserves the right to veto participation in the Sinai peace force of any contingent from a European country not fully supportive of all aspects of Camp David.

That could force the US back into its original lonely policing job. So presumably Washington feels some cold water on the Saudi plan is a price worth paying to keep the Sinai peace force as international as possible.