JIMMY CARTER could not have let the May 26 goal-date for Palestinian autonomy come and go without redoubling his efforts to reach that goal. Especially with the Europeans now threatening an end run, detachment would have advertised a degree of lassitude at odds with both the requirements of American diplomacy and his own political needs. This is the basis of his sudden invitations to Menachem Begin and Anwar Sadat for separate summits in Washington next month. The meetings force the hard question of what President Carter can do to expedite the pace of, or simply to salvage, negotiations that now look to be broken down.

There is a whole debate, more tentative in the United States and more full-blown in Europe, on the question. Is it most useful to proceed painfully step by step along the Camp David path pointing toward Palestinian "autonomy" for five years and an agreed "final status" afterward? Or is it best to accept that autonomy is a loser, to move toward the alternative goal of Palestinian self-determination and to force a confrontation with Israel, destroying Camp David and thus creating the rubble on which a new policy can be built? Most Arabs, Arabists and, increasingly, Europeans are in the second school. Jimmy Carter, not without occasionally evident misgivings, is in the first. He wants to make Camp David work.

In this he is entirely right. To abandon his chosen policy now in frustration would make the United States look like France or Britain, countries whose Mideast views flow from an Arab oil tap. No American president has the luxury of such irresponsibility. Mr. Carter must do what he can to nudge the parties closer to agreement, by May 26 and after May 26. He should also clarify to Mr. Begin the American view that Jewish settlements in the occupied West Bank are an obstacle to peace. One excellent method of clarification, as we have suggested, is to reduce Israel's aid: security yes, settlements no. Some people suggest Mr. Carter should lay off and wait for a Labor government to come to power, but that is unbecoming and uncertain and is a reward of sorts to Israeli hard-liners.

Egypt and Israel have obligations of their own. Egypt must accept, as in truth it seems ready to on most days, the consequences of its Camp David agreement to submit the Palestinian issue to a negotiation with Israel. That the negotiation goes poorly and that some of the political results are nasty does not justify sulking or quitting.

Mr. Begin apparently feels that his readiness to put the American U.N. vote behind him, and to receive renewed presidential assurances of fidelity to Israel, is his appropriate summit contribution and that, May 26 or no, he should not be expected to negotiate on autonomy at this time. This represents a breathtaking misreading of the American temper. If sustained, it can only produce a crisis. True, the option remains open to Mr. Begin, if he finds the going too difficult, to keep up the settlements, quit the autonomy talks, gather his own citizens in seige and appeal to American Jews to bail Israel out. But that would produce an ugly and dangerous situation in which even Jimmy Carter's loyalties to Camp David might be sapped. Surely it is far better for Mr. Begin to halt the settlements and negotiate on autonomy in good faith.