The bear in the Mideast

President Reagan would be the last leader in the world to pursue a course intended to give aid and comfort to the Soviet Union. But, paradoxical as it may seem, American diplomacy in the Middle East risks doing just that. Because the United States has been unable to achieve its declared objectives in Lebanon and in Palestine, the Russians are again making inroads into a region from which they had to a large extent been shut out.

The stakes for Washington these days are thus much larger than a simple withdrawal of foreign forces from Lebanon or establishment of a Palestinian homeland in the Israeli-occupied West Bank. They raise a fundamental geopolitical question: Is there to be a stable, peaceful Middle East in which every nation - Muslim or Jewish - can determine its own political future free of the Machiavellian maneuverings of Moscow? Or is there to be an increasingly contentious Middle East in which political fanaticism and religious extremism seek to destabilize existing governments and political conflict provides the soil for increased Soviet penetration?

A quick look at history may be helpful.

In the past decade the enhanced position of the US in the Middle East has been accompanied by a corresponding decline of Soviet influence. At the time of the Yom Kippur war, Washington skillfully stepped in to play the mediator. Secretary of State Kissinger prevailed on Israel to accept a military stalemate in the interests of a future peace settlement. Through a round of step-by-step shuttle diplomacy following that conflict, the US worked out military disengagement agreements: first Israel-Egypt, then Israel-Syria. Five years later President Sadat took a leap of faith and negotiated peace with Israel. As a result of the Camp David accords, Egypt - which of course had already thrown the Russians out - drew even closer to the US.

But the Camp David marathon had yet to be completed. Because the Palestine Liberation Organization and its Arab allies rejected the Camp David formula for autonomy of the West Bank, the US could not persuade Jordan to join the peace talks. Meantime the Begin government, at loggerheads with President Carter over interpretation of the Camp David agreements, proceeded to pursue its own objectives, launching a program of gradual Jewish colonization of the West Bank and ultimately invading Lebanon to deal the PLO guerrillas a blow and establish a political foothold on Israel's northern border. All, it might be added, contrary to US wishes.

Now we have the Reagan peace initiative: a creditable effort to reinvigorate the peace process by holding out a carrot to both Israel and the Palestinians. For the Israelis: rejection of an independent Palestinian state in the West Bank. For the Palestinians: Israel's withdrawal from most of occupied Arab territory and establishment of an autonomous Palestinian entity federated with Jordan. In theory, this could be a fair, just solution to an anguishing problem.

However, the United States has been unable to get the Arabs or Israel to the negotiating table. Nor has it achieved an agreement for Israeli withdrawal from Lebanon. Diplomacy seems stymied, and a shattered US embassy bears witness to a reemergence of terrorism. In Arab eyes, the US is not using its power on behalf of its own national interest and is simply letting events take their course.

And the beneficiary? The Soviet Union.

Not a few observers point out how quickly Moscow moved in to resupply the Syrians after the defeat in Lebanon, to the extent of installing SAM-5 missiles in Syria manned by Russians. President Mubarak, frustrated by Israeli intransigence and apparent American impotence, is again improving Egypt's relations with Moscow, even permitting a limited number of Soviet nonmilitary advisers back into the country. Jordan, too, has turned to the Russians for arms , and in Lebanon there is renewed talk about bringing the USSR into the negotiating process.

Needless to say, Kremlin leader Yuri Andropov is only too happy to exploit the humiliation Arab leaders feel as a result of events in Lebanon and elsewhere. The Soviet Union has long believed it is entitled to a role in ''peacemaking'' in the Middle East, and it now sees fresh opportunities to pursue that goal. As for the Arabs, who thought the United States could do the most for them, they may be having second thoughts (although it cannot be said that they have been helpful).

This is the broad context in which the Reagan administration must ponder its next diplomatic step. Will it move creatively and decisively to keep the initiative in the Middle East? Or will it let the situation deteriorate to the advantage of the Soviet Union? Secretary of State Shultz's first visit to the area may help provide an answer.