ON THE THIRTEENTH DAY of the October Arab-Israeli war, as Egyptian tanks pushed into the Iraeli-occupied Sinai peninsula, a prominent Cairo opinion maker wrote: "The issue is not just the liberation of the Arab territories occupied since June 5, 1967, but strikes against the future of Israel more powerfully and in a more profound manner...If the Arabs are able to liberate their territories by force, why should they not in the next stage liberate Palestine itself by force?"

The writer was Mohammed Hassanain Heykal, editor of the most influential Arab newspaper, Al Ahram, and as a confidant of Egyptian generals and presidents for 20 years, probably the most powerful civilian in Cairo.

On Friday evening, after a normal day's schedule including publication of a column attacking the U.S. for its pro-Israel stance and an afternoon meeting with President Anwar Sadat, Heykal returned to his apartment overlooking the Nile and heard on a radio news broadcast that Sadat had removed him from office.

Heykal's ouster is a clear sign that Arab governments, and the Egyptians in particular, are increasingly marching to an American drumbeat in pursuit of a resolution of their conflict with Israel. And more and more, the desired resolution appears to be peaceful coexistence rather than military conquest.

One of Gamal Abdul Nasser's closest friends, Heykal had long been Egypt's leading theorist on anti-Israeli policy. His most important theory, articulated at the Khartoum conference of Arab states in December 1967, was the so-called two-stage strategy for destroying the Israeli state.

Stage one involved the use of diplomatic leverage through the United Nations and the big powers to gain the return of the territories Israel had conquered in 1967. After the lands were regained, stage two, military mobilization to destroy Israel, could begin.

EVEN BEFORE HEYKAL's hasty departure from Al Ahram, Sadat had evidently decided to sweep this strategy out the door. From the very moment when Sadat came to power, his foreign policy has been one more of compromise than of confrontation. Coming in to the presidency three years after the Israelis seized the Arab lands, Sadat's problem was the daily humiliation of his people as they stared across armed lines at their own territories occupied by a foreign power.

Sadat's first step was to realize that if any concessions were to be gotten out of Israel, it was best to look to the United States for assistance, not the Soviet Union. He contacted Secretary of State William Rogers and enlisted the aid of State Department Middle East troubleshooter Joseph Sisco, but they were unable to get the Israelis to budge on the territories, which were rapidly being settled as a Zionist new frontier.

In 1971, the U.N. stepped up its mediation efforts with its special emissary Gunnar V. Jarring. Jarring issued a compromise memorandum to both sides: Egypt, he said, should commit herself to a stable peace agreement and Israel should accept in principle the right of the Egyptians to the territories conquered in 1967. Egypt agreed; the Israelis balked.

Despairing, Sadat turned to the Russians in hope of getting offensive weapons. They were willing to supply defensive weapons such as surface-to-air anti-aircraft missiles, but refused to give Egypt any planes capable of making strikes within Israel and returning home.

Feeling betrayed again, Sadat decided to listen to Saudi Arabian King Faisal, pro-American conservative among the Arab leaders, who assured him that a decisive break with the Russians would influence the United States to apply greater pressure on Israel. So in July 1972, Sadat told the Soviet military advisers to pack up and leave. Then he waited to see what the Americans would do, but nothing happened.

Next Sadat went back to Faisal and found him willing to use the much-vaunted "oil weapon" to put pressure on the United States. Faisal's first strategy, to threaten a hold up in development of Saudi reserves unless the U.S. cooperated, failed to bring results, so last October 6 Egypt attacked.

Throughout all but the very last episode of the chronicle of Sadat's efforts, Heykal was politely, but distinctly critical. And after the war, Heykal's sentiments became particularly burdensome when Sadat agreed to sit down at the bargaining table in Geneva with the Israelis.

THE REALIZATION that Sadat and increasing numbers of other Arab leaders have come to--but which Heykal, committed by 20 years of practice to a staunchly anti-Zionist line, could not allow--is that life with Israel is possible. Possible, that is, if only the constant shame of the occupied territories is ended.

The trauma caused by the establishment of the Jewish state in Palestine is now more than a generation old. The wounds are healing; the blow is now more myth than memory, easily forgotten if there are any strong forces requiring it.

By any rational standards Arabs should see no intrinsic importance in the small stretch of land that Israel occupied prior to the 1967 war. The true interests of the Arab nations lie within their own borders, in developing their own economies, raising the standard of living of their people, and for Egypt, re-opening the Suez Canal. All this can only happen in the context of secure peace with Israel.

And Sadat appears more and more to be interested in having his own little detente with the Americans. Perhaps coincidentally, on the same day he ousted Heykal, Sadat liberalized Egypt's foreign investment laws, encouraging outside businessmen and guaranteeing their investments won't be nationalized. In the same liberalization move, Sadat denationalized Egypt's movie theaters and made it easier for them to import American films. Between Lawrence of Arabia and Exodus, he hopes that popular support for settlement with Israel is bound to grow.