The Camp David summit began life as an almost invertebrate animal. Not only was there no agenda, but moreover none of the parties were operating under imperatives, or even pressures.

The upshot, provided one danger can be avoided, is apt to be what is least painful. That is an agreement for Egypt and Israel to keep talking, and a public-relations triumph for President Carter.

Consider first the position of Israeli Prime Minister Menachem Begin. He would like to work out a separate peace with Egypt, or some variant of it.

To maintain negotiations with Cairo, however, Begin has to make some generalized offer to deal with other Arab states and leaders. Egypt, the U.S. and his domestic opposition insist that the general offer should include a willingness to deliver over to Arab sovereignty a part at least of the territory now occupied by Israel on the West Bank of the Jordan River.

But the views of the Egyptians, the United States and the domestic opposition are counterbalanced by the prime minister's own backers. They want to avoid handing over any of the West Bank of the Arabs - especially the Palestine Liberation Organization. So at most Begin is under marginal pressure to make a few, largely rhetorical, concessions regarding eventual Arab sovereignty over the West Bank, and an end to the Israeli settlements and military occupation.

Sadat - ever since his visit to Jerusalem last fall - has seen himself as the historic figure who made peace between Israel and the Arab world. A bilateral Israeli-Egyptian deal is no problem.

But Egypt's economic misery is so deep that peace with Israel won't make that much difference. Sadat wants a far wider triumph - a triumph bringing in other Arab leaders. The more so as his regime depends on several billion dollars of subsidies received annually from Saudi Arabia.

Unfortunately the Saudis, despite all the court paid to them, are not a real force in policy matters. Their leaders have expressed over and over again unhappiness with the independent line staked out by Sadat when he visited Jerusalem. They do not like being in the middle of conflicts between Egypt and the Arab states, notably Syria, who are opposed to the Sadat initiative.

But the Saudis do not put serious pressure on Sadat by withholding subsidies. They are afraid that if Sadat fell, a left-wing regime would take power in Egypt and conspire with other radical Arabs to bring down the royal family.

The most the Saudis do is hold open for Sadat - in case he decides to leave off his peace initiative - the prospect of forgiveness by the other Arabs at a summit meeting. So all Sadat needs to fend off the Saudis is some sign of American backing for the Arab cause.

Which brings us to Carter. He still seems to yearn for the "comprehensive settlement" he advocated when he first came to office. So do the Arabists in the White House and the State Department. That is why they have brought to Camp David plans - including the highly risky one for an American military presence on the West Bank of the Jordan - to meet all possible contingencies.

The one great danger is that Carter, still gripped by the mystique of a "comprehensive settlement," will align himself solidly with Sadat in hopes of forcing a sweeping change in the Israeli position. Sadat would then precipitate a break in the Camp David talks, claiming he had Carter on his side, and leaving it up to Washington to force Jerusalem to its knees.

But Carter has already tried to twist Begin's arm in vain. He has - in the deal sending planes to Egypt and Saudi Arabia - seen the limit of giving carrots to the Arab leaders. His stock in this country, and in the rest of the world, is too low to risk another harsh confrontation.

So presumably he will take a less ambitious route. He will put his prestige behind a very general statement that bridges the rather narrow differences now separating Israel and Egypt on the issue of eventual sovereignty over the West Bank. The Israelis and Egyptians would then be able to continue their talks.

Carter would be seen, on millions of television sets, as an American president to whom foreigners turn to settle their differences. He would look very good, and presumably shoot up in the polls - at least until confronted with the tryly decisive issue of his presidency: inflation.