Nevertheless, Begin and Israel remain dangerously isolated in the wake of the Sinai cession. Many informed citizens in this country have started to lean tentatively toward the PLO as the seams of Defense Minister Ariel Sharon's West Bank policy shows signs of straining. Without the recent oil glut, pressure on Israel would be greater. Sadat's successor Hosni Mubarak, moreover, has indicated his desire to return to the Arab fold and will likely normalize relations with Iraq by the end of the spring. The diplomatic normalization between Israel and Egypt. Begin's main concession at Camp David has cooled considerably. Mubarak refused to visit Jerusalem last month and Israel stepped up its pressure on the Palestinians in both the West Bank and southern Lebanon. The hazy framework of Palestinian autonomy hammered out at Camp David appears more remote than ever and the ominous reflex is to embrace the PLO or to bring the Soviets into comprehensive negotiations along the lines of the 1973 Geneva talks.

This sort of approach will probably be opposed by an American administration which tries to counter Soviet influence at every step. Still, Reagan's team has already attempted to betray the promises of Camp David by backing the "peace" plan of Saudi Arabia's Prince Fahd, which died last winter because it was not radical enough for the other Arab regimes. Having sternly opposed Camp David, and witnessing a growth in their influence anyway, the Arabs have no incentive to bargain on the only issue that unites them: support of the PLO versus Israel. P>Given the history struggle over the Sinai, it is not surprising that Israelis have their doubts over the durability of the peace, particularly with an American administration showing no aptitude for the problems. And given the continuing debate over the Palestinians and the PLO the significance of the Sinai withdrawal has been taken not as progress toward peace, but as a further indication of peace's elusiveness.

PALESTINIAN WRITERS in this country have argued that the Palestinian problem is the main root of the Arab-Israeli conflict. Walid Khalidi, who with Edward Said is the PLO's best-known supporter here, argued in last summer's Foreign Affairs that by bringing the PLO into negotiations on a Palestinian state the U.S. could stabilize the region's regimes and thus defend its interests. The currents of nationalism, pan-Arabism and pan-Islam, while undeniable, pale in comparison with the Palestinian issue, he contended. All Arab regimes, whether conservative or radical are united in their support for the PLO's claims.

Before assessing this argument and its implications, or analyzing the source of Israel's and the Arab regimes respective stances regarding the Palestinian problem, a few facts-however inconvenient-should be examined:

Jordan: In September 1970, King Hussein killed 10,000 Palestinians and forced the PLO out of Jordan. Since then, Husseins's rule has gone virtually unchallenged. Yet little if any pressure has been placed on Jordan to enter negotiations on the Palestinian question, despite the fact that Transjordan (an emirate created in 1922 by Britain) composes 80 percent of the land mass of historical Palestine, and despite the fact that the West Bank was only lost when Hussein agreed to join Nasser in the folly of the Six Day War.

From 1948 until 1967, Hussein not only occupied but also annexed the West Bank, without international assent and without the population's consent. Jordan, an American client, opposed Camp David. Hussein supports the right of self-determination for Palestinians and maintains good relations with the PLO. Why? Perhaps because he'd prefer to let Israel deal with the PLO rather than welcoming the group himself. Or so history would suggest.

Lebanon and Syria: Upon leaving Jordan unwillingly, the PLO set up camp in Lebanon in 1970. Israel had never meddled in Lebanon until that point. Though Golda Meir made it clear that Israel would not sanction terrorists to its north, Lebanon permitted the PLO to gain a foothold. Joining with indigenous leftist forces, the PLO raided Christian cities until Syrian dictator Hafez al-Assad came to the phalangists' aid and began fighting the Palestinians and their Lebanese allies. Assad had observed Hussein's problems and worried about a PLO ascendance.

The Syrian initiative, described as an attempt to keep the peace, succeeded in taming the Palestinians. But Assad, who has recently supported Iran against Iraq in order to tip the scales of the balance of power to his advantage, was not sated. He joined the PLO and betrayed the Christian minority. Today more than 30,000 Syrian troops are entrenched in Lebanon; surface-to-air missiles are aimed at northern Israeli cities; 100,000 Lebanese citizens have died.

The fighting continues. Israel has bombed PLO enclaves, and though it is cavalier to compare casualties inflicted, those attributable to Israel do not begin to approach those attributable to Syria and the PLO. For its consistent opposition to the PLO, Israel has been branded the main obstacles to peace; for its persistent inflammation of a tragie civil war, Syria has escaped condemnation because it is not an ally of the United States but of the Soviet Union.

Besides his hegemonic ambitions and fear of the PLO, there is another reason for Assad's adventurism in Lebanon. As minority ruler, he is under siege from his Moslem opponents domestically. When he ventures into Lebanon to divert attention from his problems at home, an American mediator negotiates a cease-five which allows him to keep his missiles trained on Israel. When Menachem Begin ventures into Lebanon in pursuit of terrorists who oppose his state with every means at their disposal-partly to divert attention from the painful operations in the Sinai necessary for peace-he is accused of ignoring his American ally and of loving war.

Saudi Arabia: The night that the Saudis had extracted the largest single arms sale ever from the United States Senate, its ambassador to the U.N. declared on national television that Saudi Arabia had already done "enough" for the Camp David process. What was "enough?" Nothing, save the isolation of Sadat and the unequivocal rejection of the accord.

That happened last November. Previously, the Reagan Administration's cornerstone of its Mideast strategy (insofar as one could be divined) involved an all-out attack on Lybia's Muammar Qaddifi. Saudi Arabia, obviously very impressed with the tacit quid pro quos which attend a bilateral arms deal, obliged by restoring diplomatic relations with Libya. And when Weinberger arrived in Saudi Arabia earlier this year, he negotiated all night to get the Saudis to sign a communique supporting the much-heralded anti-Soviet consensus. Through perserverance, Weinberger won a remarkable concession: While the Saudis resisted signing the communique, they agreed that a Sultan would sit in at the press conference. How's that for prudent use of political capital?

ISRAEL, AND BEGIN, cannot escape culpability for its part in the conflict's persistence, especially as shown by such provocative actions as the unilateral removal of the elected mayors on the West Bank and the unnecessary annexation of the Golan Heights. But it seems evident from this admittedly brief discussion of the Middle East's complexity that the source of the Arab-Israeli conflict is not primarily the Arab support of the PLO and the Israeli opposition to it as Khalidi argues.

Instead, the one issue that unites Arabs is a common hatred of Israel, apparently reinforced by a common fear of the PLO. Jordan and Lebanon have suffered from the PLO's presence, with Hussein scarred and Lebanon gutted. Syria and Saudi Arabia have no desire to follow in those menacing footsteps. With the Palestinian problem solved through the involvement of Jordan, Egypt. Israel and the PLO, the common fear of the PLO may attenuate. But the internal difficulties of these Arab regimes and the growing pan-Islamic tide led by Iran will not simply disappear. Neither, will Israel, nor presumably, will the common hatred of Israel. Whether out of the need for an external enemy for internal unity, or out of revanchist motivations, it is safe to assume that Israel will remain an object of enmity. Israel's security needs logically become paramount.

And Israel currently sees the PLO as anathema to its security although many reasonable Israelis recognize that some kind of Palestinian automony in the West Bank and Gaza is inevitable, if only for demographic reasons. And the PLO an umbrella organization which encompasses 55 separate branches, seems the most visible and most likely representative of the Palestinian people. But rushing to include the Soviet-backed PLO in bargaining does not immediately ensure a settlement favorable to any party, let along all parties.