Yasser Arafat is a master in ambiguity and political maneuver. But he should know that the document which he signed for a bipartisan group of US members of Congress accepting all UN resolutions that include Israel's right to exist - and the subsequent statement of a PLO official that the statement excluded two key Security Council resolutions - have done little to enhance his credibility with American public opinion. They have created even more confusion and deflected attention from what is the more immediate objective of US diplomacy - to work out a plan for the evacuation of the PLO from Lebanon.
In fairness, however, the fault probably lies most with the congressional visitors. Their intentions may have been honorable. But it is doubtful that injecting themselves into a highly charged and complex situation in the midst of delicate negotiations has proved helpful. It does not look as if they got anything from Mr. Arafat which he has not said before. The PLO leader did not specify UN Resolutions 242 and 338 in writing or mention Israel's name - something the US would certainly demand if it were to agree to recognition of and direct talks with the PLO.
Perhaps not wishing to foreclose dialogue with members of the US Congress, Mr. Arafat chose to receive Rep. Paul McCloskey and his colleagues. But it seems clear he was not prepared to use them as the conduit for a significant change in the PLO position, thereby bypassing the Reagan administration. They, in turn, may have run the risk of leading him to think he could extract a change in US policy without giving something in return: namely, an unequivocal acceptance of 242 and explicit reference to Israel's right to exist.
For Mr. Arafat, of course, such a declaration poses problems. He risks losing everything - his political as well as military influence - if he does not make recognition of Israel contingent on reciprocal recognition of Palestinian rights to self-determination.
Is it possible to cut through this tangle? Is Arafat prepared to recognize Israel? Is the US prepared to deal directly with the PLO? Provided conditions are met on both sides? The Israel invasion, paradoxically, has created a fresh opportunity to come to grips with this issue and and to move ahead diplomatically on the whole Palestinian question. Experienced observers think the US and the moderate wing of the PLO can come to agreement. But, with the clock ticking away and Israel threatening a military assault on west Beirut, the urgent priority is to get the PLO fighters out - the issue which several Arab nations take up in crucial meetings this week.
If the Arabs are seriously interested in peace, they will have to show more concern for the PLO guerrillas than they have to date - and agree to some plan for harboring them. Once the threat overhanging Beirut is removed, Washington can return to the PLO recognition issue and the pursuit of a comprehensive peace. From Mr. Arafat's standpoint, this does entail risk, and that is no doubt why he has been maneuvering for time to gain diplomatically what he has lost militarily. But he must realize that President Reagan, after the cruel devastation of Lebanon and the political and military mess this has created, can no longer ignore the plight of the Palestinians - or the existence of the PLO.
That, it is to be hoped, is what the US is telling him.