The prospect of mass protests against the peace campaign of Egyptian President Anwar Sadat or of unified action by his Arab foes to head him off is fading like a mirage in the desert.

The shock of the Camp David agreements is wearing off. Contrary to the fears of Sadat's friends and the predictions of his enemies, there has been no surge of popular unrest against Sadat anywhere in the Arab world. Nor have the radical governments that oppose him succeeded in mobilizing enough support to trouble him.

Inside Egypt there has been only a brief ripple of dissent from predictable soucres: Islamic extremists and the minuscule left.

In other Arab countries, the lack of outcry among the population has lent support to the Egyptian argument that most ordinary Arabs want peace and support Sadat as campaign to get it, even if they disagree with some of the terms he has accepted.

This is not to say that there is much enthusiastic support among other Arab rulers for what Sadat is doing. But there is a combination of resigned acceptance and pragmatic recognition of Egypt's position that has prevailed over the rhetorical outbursts of the extremists.

As he did when he signed the military disengagement agreements with Israel after the 1973 war and when he broke with the other Arabs to visit Jerusalem last year, Sadat has challenged and defied his critics, rather than conceding anything to them, and he has gotten away with it.

After the Jerusalem trip, he denounced his most strident opponents, such as Muammar Qaddafi of Libya, as "dwarfs" and "ignoramues." His language has hardly softened since the Camp David summit meeting.

Sadat gambled that he could persuade Arab moderates to stay out of the campaign against him and that the extremists lacked the strenght to give him real toruble. As foreign ministers met in Baghdad to lay groundwork for an Arab summit called to seek ways to undercut the Egyptian leader, he appeared to have won both bets.

At least eight of the 22 Arab states have said publicly or let it be known unofficiolly that they will oppose any attempt at that conference to "isolate" Egypt, bring down Sadat or engage in any active campaign against this country.

The most important is Saudi Arabia, whose foreign minister, Prince Saud, said over the weekend that "nothing can break the ties between Arabism and the Egyptian people . . . Egypt is an integral part of the Arab nation."

With the Saudis taking this approach, it seems assured that the pro-Western and neutral moderates will be able to hold off any attempt by the radicals to turn the summit into an anti-Sadat campaign.

It is a measure of how high feelings have run that Egypt - which is the seat of the Arab League, has by far the biggest Arab population and has done most of the fighting in four Arab wars with Israel - was not invited to the summit conference. An Arab summit without Egypt would have been unthinkable before Sadat's trip to Jerusalem.

But Sadat has made it clear that he is not interested in insults. He is interested in a negotiated peace with Israel. Egyptian officials say they are confident that the gough line Egyptian negotiators are taking in the Washington peace talks and Egypt's insistance on linking a treaty with Israel to progress on the Palestinian issue will enable Egypts friends at the summit - Morocco, Sudan, Tunisia, a few others - to neutralize the radicals.

This was not so clear even a week ago. At the time, the Saudi position was uncertain, and it seemed possible that the stunning reconciliation between Syria and Iraq might swing the Arab balance of power against Sadat.

Observers here believe, however, that there may be less than meets the eye to the Syria-Iraq partnership.

Syria is still affirming that it seeks a negotiated peace with Israel on the basis of U.N. Security Council Resolution 242. That resolution was adopted in the Camp David accords as the basis of negotiations over the future of the occupied Arab territories, but the Iraqis have never accepted it because it implies recognition of Israel.

Observers familiar with Syrian affairs also take lightly the announcement that Syria, and Iraq will pool their military resources to confront Israel. Syria, they say, does not want and cannot afford war with Israel and is not likely to do anything to provoke it - such as allowing large numbers of Iraqi troops to move up to the Golan Heights.

In an interview on French television, Syria President Hafez Assad said Syria and Iraq plan "to reorganize our defense systems in such a way that we can defend ourselves efficiently against any new attack, any new aggression." That is not seen here as a formula for effective action against either Sadat or Israel.

Egyptian officals say they have indications that despite the vigorous protests against Camp David by the Palestine Liberation Organization, the PLO may in fact be prepared to authorize some Palestinians to negotiate with Israel rather than risk getting nothing.

Similar reports have emerged from Palestinian sources in Beirut.

All this leaves Sadat in a position where he can press ahead without having to look over his shoulder - but it also reinforces Egyptain determination to prove that this country really does not want a separate peace, Egyptain officials say.

In their view, there were several reasons why the other Arabs have not been able to act effectively against Sadat.

One is that the masses of the people either support Sadat or are indifferent, the Egyptains say, preferring in any case the possibility of peace to the threat of another war.

Another is that time has demomstrated that Sadat's approach works and none of his opponents has offered any effective alternative strategy that would regain any of the Arab lands occupied by Israel.

And finally, they say, it is absurd to talk of Arab solidarity or unity, or to try to develop any unified Arab strategy, without Egypt, the biggest Arab county and still its greatest military power.