A change in forces on the ground has worked strategic transformatin in the Middle East. So the United States and its closest allies now need to rethink their basic approaches.

But a prior condition is that the Reagan administration develop a way to formulate policy that goes beyond the playing-off of one adviser against another. For the chops and changes of the past week, and the harsh personal attacks on Menachen Begin, serve only to obscure the fact that something deep and dangerous has occurred.

The general strategic position in the area used to rest on a rogh stalemate between Israel and the Palestine forces based in Lebanon. The Palestinians limited their efforts to sporadic terrorist raids across the border. The Israelis held these in check by relatively low-level retaliation.

Recently, however, the Palestinians have acquired the capacity to hit towns in northern Israel with rocket fire from bases in sourthern Lebanon. Israeli retaliation was stepped up accordingly. Hence the air raid on Beirut July 17, aimed at the military headquarters of the Palestine Liberatio Organization, which brought more death to more than 300 persons.

The ethical bookkeeping that condemns the raid because of the number of fatalities lacks moral authority. It frees the PLO from responsibility for provocation and implies that, if only three innocent people had been killed, retaliation would have been okay. But for practical purposes, Israel cannot maintain, and the United States cannot support, retaliatory strikes on such a scale. So what comes next?

The cease-fire announced Friday is the obvious first step. The accord, however, depends on the Palestinians. But the Palestinians can only be engaged by some motion toward a political settlement in the predominantly Arab territories occupied by Israel after the Six-Day Was of 1967. That raiss the issue of negotiations for Palestinian autonomy prescribed by the Camp David Accord between Israel and Egypt. That, in turn, leads to the basic Mideast policy of the Reagan administration.

The administration had hoped to "leapfrog" the autonomy talks by achieving a "strategic consensus." The strategic consensus was to link Egypt and Israel with Saudi Arabia and other anti-communist states in the region. But that approach has come apart with the policy of retaliation.

For when the Israelis wiped out an Iraqi nuclear installation, the United States then teamed up with Iraq to condemn Israel in the United Nations. When the Israelis threatened to wipe out missles moved by Syria into Lebanon, the United States engaged the Syrians in negotiations.

Saudi Arabia encouraged both those moves. But Iraq and Syria are ruled by left-wing regimes allied with Moscow. Not only were the Israelis upset, but Egyptian President Anwar Sadat was driven wild with fury by what he perceived to be support from Washington for Arab rivals in Damascus and Bagdad. Indeed, when Jehan Sadat lunched with Nancy Reagan at the White House in March, Sadat tried to pass word to Reagan that he was even disturbed by American courtship of the Saudis.

That well-nigh desperate effort to communicate suggests what went wrong with American policy. The "strategic consensus" meant all things to all people. For Secretary of State Alexander Haig, it centered on Egypt and Israel. To Secretary of Defense Caspar Weinberger, it featured Saudi Arabia. Ambassadors in the field thought it meant engaging Iraq and Syria. To presidential counselor Edwin Meese, it was a way of keeping Reagan's foreign policy options open while he concentrated on domestic affairs.

The disarray came sharply to the surface after the bombing of Beirut. At first, up in Ottawa, Haig and Meese sounded as though relations with Israel were not affected. Then Begin put off a proposed cease-fire with Lebanon by 24 hours. The president suddenly decided to suspend delivery of 10 fighter planes earmarked for Israel. That angered Begin, who backed away more on a cease-fire. Weinberger then weighed in with some nasty personal remarks about Begin that threatened to make him madder, and caused other Israelis to rally round their leader. So next day, James Baker of the White House staff disavowed the Weinberger comments.

With genuine danger brewing, and with Sadat coming to Washington early next month and Begin shortly thereafter, the United States plainly needs to get its Middle Eastern act together. My own sense is that the shifting sands of the region offer a poor base for the building of an anti-communist alliance. I think the "strategic consensus" has to be abandoned, and I see no alternative except patient negotiations with Egypt and Israel for progress on Palestine autonomy.

But whatever path is chosen, the making of policy by letting a hundred flowers bloom cannot safely continue in the Middle East.