The United States and its West European allies, still seeking to compose their differences over the Iran and Afghanistan crises, may soon find themselves on opposite sides of the Arab-Israeli conflict as well.

Such a cleavage seems unavoidable if the U.S.-led Camp David process fails to produce to workable agreement between Israel and Egypt on self-rule for the Palestinian inhabitants of Israeli-occupied territories.

As Adm. Stansfield Turner, director of the Central Intelligence Agency, told a Senate committee Tuesday, Western Europe, with its heavy dependence of Mideast oil, is increasingly concerned that the autonomy talks won't get anywhere and is cranking up alternative proposals that "would reflect a more pro-Palestinian, pro-Arab stance than the Europeans have taken so far."

A specific European initiative isn't likely before midsummer at the earliest. For the present, the West Europeans are in a holding pattern, waiting to see what results from the up-coming making-or-break phase of Egyptian-Israeli negotiations.

But most West European governments are operating on the assumption that the talks will fail or, at best, come up with an accord tilted so strongly toward Israeli's insistence on severely restricting Palestinian autonomy that it will be unacceptable to the Arab world.

If that proves to be the case, the nine nations of the European Economic Community, led by France and Britain, are expected to spearhead an effort in the United Nations to gain international recognition for the right of the Palestinians to "self-determination' and of the Palestine Liberation Organization to participate in the Mideast peace process.

Their rationale would be that failure of the Camp David initiative had left a void in the Middle East that must be filled by the other members of the Atlantic alliance if the West is to preserve its influence in the region and ensure continued access to its vital oil supplies.

In pushing that argument, the Europeans would contend that their aim was not to undercut U.S. efforts but to supplement them by giving the West leverage with Midwest forces that Washington cannot deal with because of its commitments to Israel. That is a strategy with which many U.S. diplomats privately agree.

The problem, though, is that such a West European initiative would arouse furious opposition from Israel. And the complexities of the U.S.-Israeli relationship, particularly during a time of American presidential elections, almost certainly would force Washington, whatever covert sympathy it might have for the European initative, to side with Israel.

The result could be a confrontation that would see the United States vetoing a U.N. Security Council resolution on the Palestinian question over the objections of the Europeans.

That, according to this schedule, would have the effect of isolating the United States as Israel's only remaining friend, increase the erosion of U.S. influence with key Arab states such as Saudi Arabi and Jordan and cause considerable new acrimony in U.S.-West European relations.

Although the Europeans have been careful to stress that they're not trying to work at cross purposes with the United States, there nonetheless are some very strong undercurrents of rivalry in the situation.

That is especially true of France, whose president, Valery Giscard d'Estaing, has been moving more and more openly to emulate the efforts of his predecessors, Charles de Gaulle and Georges Pompidou, to turn the EEC into a French-led "third force" capable of competing with the United States and the Soviet Union for political and economic influence on a global scale.

On a recent tour of the Persian Gulf, Giscard pulled out all the stops in championing the cause of Palestinian self-determination. Implicit in his statements and actions was the unmistakeable suggestion that the United States is tied too closely to Israel to be a dependable ally of the Arab world and that Western Europe, with France in the forefront, is prepared to replace Washington as the protector of the Gulf states.

In a less grandiose fashion, the competitive instinct also appears to be a factor in the calculations of Britain, the other EEC member that has been active in proclaiming the urgent need to resolve the Palestinian question.

In Britain's case, the desire for close relations with the Arab world is motivated in part by concern about preserving and, if possible, increasing Britain's share of the lucrative Mideast trade and banking business.

Saudi Arabi, for example, has been transmitting signals that coninued U.S. failure to get a Palestinian solution might cause it to shift a lot of its business to countries that it regards as more sympathetic to the Arab cause. Such a move by the Saudis would be followed by many of the region's wealthy oil sheikdoms, and Britain undoubtedly would be among the prime beneficiaries of the shift.

Once before, following the oil embargo imposed by the Arab countries in late 1973, similar considerations led France and Britain to team up in an attempt to lead the EEC into playing an Arab-oriented broker's role in the Middle East conflict.

That effort failed, largely because Israel's opposition caused its friends within the EEC, principally West Germany, the Netherlands and Denmark, to balk at getting too entwind in what looked like an overtly pro-Arab initiative.

This time, however, a combination of growing impatience over what the Europeans regard as Israeli intransigence and concern about their oil supplies has caused the nine, together with Norway, a non-EEC member, to draw together behind to idea of a U.N. initiative aimed at the Palestinian problem.

In fact, U.S. officials say, the West Europeans haven't forced the issue only because of a tacit agreement to wait until the autonomy talks pass their May 26 target date, and because of disputes among the United Nation's Arab-bloc members about what form a Palestinian initiative should take.

The idea discussed most often involve a possible attempt to rewrite U.N. Resolution 242, which is the basis of all Arab-Israeli diplomacy, in a way that would recognize the Palestinians' right to self-determination in exchange for an implied Palestinian acceptance of Israel's right to exist.

European diplomats argue that such a trade-off -- whether accomplished through an amendment of 242, through passage of another resolution through passage of another resolution or through some other means -- offers the only real hope of breaking the 32-year-old impasse in the Middle East.

As sketched by the Europeans, this game plan would enable them, through their out-front support of the initiative, to work on winning the confidence of the PLO and the Arab states. Then, once the U.S. presidential election is decided on Nov. 4 the U.S. government would be in a position to put pressure on Israel to come into line.

The Europeans also point out correctly that many U.S. officials, particularly within the State Department and the American mission at the United Nations, share the view that, if the autonomy talks fail, some new and broader approach to bringing the Palestinians into the peace talks will become imperative.

Last summer, the State Department, despite its denials, was known to be exploring the possibiities of drawing the PLO toward acceptance of Israel. That move was aborted hastily after U.N. Ambassador Andrew Young was caught in an unauthorized contact with a PLO official and forced to resign.

But, although the Carter administration since has steered clear of that track, it still contains officails who believe the PLO must be brought into the peace process and who, in private, talk wistfully about the chances of U.S. cooperation with a European initiative if the autonomy talks fail.

What the Europeans have over-looked, though, is that incidents like the Young resignation and President Carter's more recent disavowed of a U.N. resolution criticizing Israel have caused those officials who think that way to be increasingly out of favor at the White House.

At a time when Carter is struggling to overcome suspicious among Jewish voters that he has an anti-Israeli bias and when his campaign strategists are muttering darkly about the "Arabists" in the State Department, there is little chance of Washington's giving any encouragement to an initiative that Isreal regards as anathema.

Nor is there much realism in the idea that Carter, or whoever emerges as president in November, will have more freedom to go to the mat with the Israelis after the campaign is over.

U.N. officials say the Arabs and West Europeans tentatively are talking about beginning a Security Council debate on the Palestinian issue on July 15. That's one day after the opening of the Republican National Convention in Detroit that now seems likely to nominate as its presidential candidates Ronald Reagan, a man committed to a strong pro-Israeli stance.

Given that timing, Carter is hardly likely to let his U.N. representatives stand by passively and allow the Security Council to pass a pro-Palestinian resolution that would expose the administration to a barrage of criticism from Detroit.

Instead, the dynamics of the situation are such that both parties will be spending much of the summer and fall competing for Jewish votes with promises of support for Israel, and whoever wins will not find it easy to get out of these promises after November.

For the present, U.S. officials concede, Washington's best course is to bend every effort toward making the autonomy talks succeed in a way that will ward off the confrontation building up at the United Nations.

If that effort fails, the officials add, the Europeans almost certainly will move ahead with their Palestinian initiative. And, they add, the end result is likely to be not progress toward the elusive goal of Middle East peace but a new series of acrimonious strains in the Atlantic alliance.