SECRETARY OF STATE Alexander Haig, returning from Israel and Egypt, says he sees no prospect of an agreement on Palestinian autonomy before April 26, when Israel is scheduled to complete its evacuation of Sinai. This is a portentous report. It evidently means the secretary has abandoned any thought of putting the American diplomatic foot to the floor in the foreseeable future. It means that while the Egyptian-Israeli part of Camp David remains live and valid, the signers' mutual commitment to address the Palestinian part is declining. For if Mr. Haig can see no prospect for agreement before April 26, no one else can see any prospect for agreement after that date.

Just why Secretary Haig is easing away from the Palestinian question is not hard to surmise. The Begin government in Israel is pulling back from full delivery on its Camp David pledges. The new Mubarak regime in Egypt, eager to get back in with its fellow Arabs, seems to be hardening its autonomy terms. King Hussein of Jordan is caught up in intra-Arab intrigues. The Saudis have just spurned their own peace initiative. The PLO is in a defiant phase. Nor is it simply that foreign parties and partners are out of sorts. In Washington there is neither a bureaucratic consensus nor a presidential focus on Mideast policy.

In those circumstances, a case can be made that the United States should avoid the large risks of pushing a Middle East initiative. Better to wait until things look a bit more promising. Why fall on your face now? There is, after all, an alternative: limping along, muddling through. The Israelis would be pleased at that, since it leaves them relatively free to go ahead with their plans for the West Bank. The Arabs would stew, but such are their divisions, distractions, vulnerabilities and other anxieties that the United States could reasonably expect to play them along.

We think, nonetheless, that it would be shortsighted and dangerous for the United States to follow this line. It leaves the United States as something at the whim of a client--an indignity which no great power can afford or should allow itself to suffer. It exposes the United States to considerable unnecessary costs in dealing with a range of states in normal times, and to immense unnecessary costs in emergency times. To let the Palestinian question go unresolved undercuts American ideals of fairness and justice. To let Israel go on undercutting its own long-term interests is to evade the first, if most difficult, duty of a true friend.

We are not saying that the administration should throw itself into a hastily contrived, half-baked diplomatic campaign tomorrow morning. It would be unforgivable, however, if it let the Palestinian part of the Camp David process atrophy or lapse. From any point of view, that process has its shortcomings. But it provides the only available vehicle to accommodate Israeli, Palestinian and American interests, all of which must be accommodated if there is to be peace.

The administration has been lazy-minded and less than lion-hearted in its approach to Camp David. It has evaded the difficult labor of fitting together a policy, and it has shrunk from the difficult contests with Israel--and not only with Israel--that further application of Camp David will inevitably bring. Mr. Reagan should no longer evade this challenge.