The most significant foreign policy achievement of the United States in many years was its successful sponsorship of the Camp David Accords. Negotiations between Israel and Egypt led to a peace treaty under which Egypt receives back the Sinai, and Israel obtains peaceful relations with the largest Arab nation. Both nations agreed to negotiate further on interim arrangements concerning the autonomy of the Gaza Strip and the West Bank.

It is difficult to understand why any informed observer would suggest or support a subversion of the Camp David Accords. The so-called "Fahd peace plan" is such a subversion. If the Saudis are moderate, want peace and will accept the continued existence of Israel, why don't they simply say so?

Secret Saudi assurances given on isolated occasions in private meetings do not outweigh the public intransigence of Saudi leadership. Philip Klutznick may be won over by kind words whispered by a "modest, but anxious" Saudi sheik, but they form no firm basis for American foreign policy. The Anti-Defamation League of B'nai B'rith respects Klutznick for his distinguished service to the Jewish community. However, his opinions (as expressed in "Let's Listen to the Saudis," op-ed, Nov. 15) do not correspond with the position of the league or with reality.

What are the real issues?

* The Palestinian problem, assertions to the contrary notwithstanding, is not the central issue of the Arab-Israeli conflict and is not the key to peace. Klutznick reports the Arabs to say that if only the Palestinian problem were resolved, the Arabs would be ready for a comprehensive peace. In truth, there is nothing new in this approach. We have heard such talk from the Arabs for years.

Anwar Sadat recognized that the "Palestinian issue" was not the key to peace in the Arab world. He understood that Israel could not accept vague promises of Arab moves to peace conditioned upon Israeli capitulation on all specifics. Sadat realized that true peacemaking and a psychological breakthrough required two steps: 1) a public demonstration of an unequivocal desire for peace, which he showed by his trip to Jerusalem and, 2) a willingness to sit down and negotiate differences between the parties.

Klutznick misses the crucial point when he proclaims a new Arab moderation in the so-called Saudi "peace" plan. Even if one were to interpret point seven of the Fahd plan--"All states in the region shall live in peace"--as including Israel (some Saudi spokesmen have denied that Israel is a legitimate state), the Saudis are not offering to work out their differences through negotiations. They say: "Take it or leave it."

The refusal to negotiate without preconditions, the insistence that Israel accept beforehand a return to the perilous 1967 borders, indicates one thing: that the Saudis have devised a tactical ploy to weaken Israel so that the Arabs can more ably continue their war against the Jewish state.

* Moderate Palestinians would emerge and negotiations can be facilitated only when it is made clear that the PLO will have no place in the process.

Klutznick reports that the PLO is the only party qualified to speak for the Palestinians and that it has the power to accelerate or abort the peace process.

It is the repetition of this clich,e that gives the PLO a veto on Middle East developments that it hasn't earned and need not possess. The PLO does not want and cannot bring a peace policy. Its charter demands the destruction of Israel. That fundamental truth, together with the understanding that Western policy has given the PLO much of its standing, should guide our thinking. We must begin to foster the notion that peace does not need, indeed must do without, the PLO. It is only through that kind of process that true moderates may emerge or, as remote as it may be, that true moderation of the PLO may take place.

* The PLO's program for elimination of Israel remains intact, and is in no way diminished by the organization's newly developed social and economic institutions.

Klutznick says the PLO is an organization that increasingly is dealing with social and economic problems, thereby taking on the appearance of something more than a military institution.

This statement obviously is intended to demonstrate a new PLO moderation and respectability. It reveals neither. This existence of social and economic institutions says nothing about moderation. The PLO would undoubtedly be eager to set up all kinds of institutions in the territory that is now the state of Israel. Extremism or moderation is judged by political positions and by the use of terror and assassination to snuff out true moderates. On that score, the PLO remains as extreme as ever.

* Saudi moderation would be helpful to peace, but it hasn't revealed itself to date and can only come through a strong U.S. policy toward the Saudi sheikdom.

The Fahd plan, as noted, does not reflect moderation, and, as Abba Eban has written, "If one wants to help bring about a change of Saudi policy, the worst thing to do is to pretend that the desired change has already occurred."

The Saudis cannot and will not change by themselves. Change can only come through a new U.S. relationship with Saudi Arabia, reflecting U.S. strength and the fact of Saudi Arabian dependence on a strong United States. Only then might the Saudis consider true peace with Israel, as Anwar Sadat did four years ago.