Sinai tightrope

US government officials responsible for trying to bring peace to the Middle East agree that there is not a thing they dare do between now and April 26 to get the Camp David process going again.

Any pressure from Washington on the government of Israel during this intermediate time could, it is agreed, wreck present progress towards a decisive peace between Israel and Egypt. Washington greatly wants that part of Camp David to be concluded as scheduled on April 25.

So great is the concern about the Israel-Egypt peace settlement that, in effect, it gives Israeli Prime Minister Begin the time to proceed both towards the peace with Egypt and consolidation of Israeli control over the West Bank and Gaza Strip. His progress towards annexation is covered by Washington's anxiety about the peace with Egypt.

The prospect therefore is that by the morning of April 26, when Israeli troops are supposed to be out of the Sinai peninsula, the Israelis will have so consolidated their grip on the West Bank and Gaza that it will be too late for Washington to get Camp David going again.

This means that what Washington has always wanted most out of the Camp David process will be almost hopelessly out of reach.

Step back at this point and consider what each party to Camp David has wanted out of it.

Egypt wanted to regain its lost lands in Sinai and an opportunity to concentrate on its domestic problems free of the danger of another war with Israel.

Israel has wanted peace with its largest Arab neighbor, Egypt. This will give it security on its southern flank and the ability to concentrate on its territorial ambitions to the east and north.

But what the US wants now, as it has ever since the coming into existence of Israel in 1948, is a comprehensive peace between Israel and all of its Arab neighbors. Washington wants that because unless and until such a comprehensive peace comes into existence it is impossible for the US to pursue friendly relations with the Arab states of the Middle East.

Until Washington can appear in the Middle East as a friend of the Arab states , those Arab states will of necessity look to Moscow for help against what to them seems to be an alliance between the US and their enemy, Israel.

Or, to put it more simply, what the US wants most in the Middle East is to keep the Soviets out of the region. But it can do that only by first leading or persuading Israel to enter into a comprehensive peace with all of its Arab neighbors. At that point Washington comes up hard against Mr. Begin's determination to hang on to what he calls ''Judea and Samaria.''

The essential fact is that in no way can Israeli annexation of the West Bank and Gaza be reconciled with Washington's desire to keep the Soviets out of the Middle East, for the simple reason that no Arab, or Muslim, can accept the idea of annexation as being anything but hostile to the interests of the Arab community in particular and of the Muslim community in general.

The Arab world and the whole of Islam will hold Washington responsible for a disservice to them if it allows Israel to seize and consolidate into Israel itself the inner walled city of Jerusalem, the West Bank, and Gaza. If that happens they are bound to seek to use Moscow as a lever to obtain redress in the Middle East. And then the bear's paw is back once more among the date palms of Arabia.

American diplomacy from the days of President Eisenhower and Secretary of State John Foster Dulles has yearned for and sought by all possible means to keep the Soviets out of the Middle East.

That objective of so much American diplomacy over so many years is achievable if Camp David's formula for ''full autonomy'' for the Arabs of the ''occupied territories'' is consummated sometime after the conclusion of Israel's peace with Egypt on April 25.

But I know of no Western (or Eastern) diplomat who thinks that the goal can be reached if Israel is allowed to annex the walled inner city of Jerusalem, predominately Arab East Jerusalem, the West Bank, and Gaza.

Down that road lie the Arabs turning to Moscow, the probability of yet another Arab-Israeli war, and a dangerous involvement of both Washington and Moscow in such a war.

By the morning of April 26 Israel will have de facto possession of all those lands which Mr. Begin claims.

Can President Reagan then persuade Mr. Begin to let go of those lands and set free the Arabs (1.2 millions of them) who inhabit those lands? The chances are that Mr. Begin will have won a major victory for Israel's expansionists. But it will be a major defeat for American diplomacy and American interests.