NECESSARILY the second Sadat-Begin summit, at Ismailia, went beyond the heady symbolism of the first meeting in Jerusalem and brought the two leaders face to face with the stubborn core of the Arab-Israeli dispute - the Palestinian question. They could not agree. Though the new Israeli position calling for West Bank - Gaza self-rule represents a major Israeli departure, it did not satisfy the Egyptian demand for Palestinian statehood, a position consistent with Cairo's obligations and loyalties to other Arabs.

Instead of the joint statement of principles for a general settlement that hadbeen widely hoped for, the Ismalia meeting produced an agreement to continue negotiations at the ministerial level inspeparate political military committees in Jerusalem and Cairo respectively. THese talks, which will supplant the already-interruted "Cairo conference," are expected to begin in mid-January and go on for two or three months. Peace, not determined by anyone's sacred calendar, did not break out on Christmas day.

We share what we take to be the general disappointment. But, some fevered press comment notwithstanding, we are not all inclined to conclude that the negotiations has been derailed. It was inevitable that the Egyptian-Israeli dialogue would slow to a pace reflecting stickiness of the basic issues - and it is also a healthy development. It seems evident from accounts of the Ismailia meeting that while Mr. Begin presented a new Israeli position on what he calls "Samaria and "Judea," Mr Sadat presented the familiar Arab position on the "West Bank." If, as appears least likely, the Israelis have not yet projected a strong enough sense of ultimate Arab sovereignty over this territory, then the Egyptians have not yet taken fully into account Israel's own special requirements. In any event, that the two men tackled the Palestinian question, and agreed to continue tackling it, is hard evidence of their sincerity in seeking a settlement not limited to their own relatively simple bilateral nees. This should give Mr. Sadat in particular the defense he needs to ward off radical Syrian and Palestinian charges of "selling out" the Arab cause.

"For sure we shall find a solution," said President Sadat. Prime Minister Begin expressed similar confidence. Both men, we believe, are deeply committed to their quest. They have not only made a total political commitment to it; they are proceeding with an open-eyed sense of the historic opportunity lying before them. Any delay in the negotiating process carries with it a definite risk of external upset, and also of internal difficulties. Yet the greatest risk was to start down the road toward peace. First Mr. Sadat and then Mr. Begin took that risk, and they have not lost their drive or nerve.