An unprecedented statement by prominent West Bank Palestinians condemning an anti-Israeli terror strike could presage a new Arab initiative for a negotiated Middle East settlement.
Much depends on developments elsewhere in the Arab world - especially the future of Palestine Liberation Organization leader Yasser Arafat and of his major foe, Syrian President Hafez Assad. The positions of the United States and Israel will be crucially important.
But the public denunciation Thursday of the attack from five important Palestinian figures on the Israeli-occupied West Bank and in Arab east Jerusalem seems at least to suggest some serious rethinking among Arab moderates.
The signatories included several longtime Arafat sympathizers, and one figure closely identified with Jordan's King Hussein. Among the Arafat sympathizers was Mustafa Natche, former mayor of Hebron, a West Bank city.
Mr. Arafat's spokesmen - as well as the Syrian-backed rivals he has been fighting in the north Lebanese city of Tripoli - had raced to claim long-distance responsibility for the attack the West Bankers have now denounced.
It occurred Tuesday. A bomb was placed on a Jerusalem city bus, killing four passengers, including two children, and injuring several dozen people. The claims of responsbility spoke of the successful bombing of a ''military'' bus.
The subsequent Palestinian denunciation of the attack is remarkable for several reasons.
It is public and explicit. ''It is our belief that attacks (by either side) on civilian targets are detrimental to any Palestinian-Israeli understanding,'' says the statement.
It brings Arafat supporters and King Hussein's camp on the West Bank into rare public alliance.
And at least implicitly, the statement amounts to a rare breaking of ranks with Arafat by prominent sympathizers on the West Bank.
Western diplomats felt that the presence among the signatories of Anwar Nusseibeh, pro-Jordanian director of the East Jerusalem Electric Company, meant the move had received at least tacit approval from King Hussein.
Whether the presence of other figures identified with Arafat's policy line meant he, too, had nodded some kind of OK from Tripoli was much less certain. Two explanations seemed possible:
Either Arafat gave some sort of green light, or the West Bankers acted on their own as a signal of which way they'd like to see Arafat policy go after extricating himself from the civil war in north Lebanon.
The Reagan administration has made no secret of its hope King Hussein will actively join Middle East peace negotiations in conjunction with local Palestinians on the West Bank.
Israel has shown some recent interest in such a move as well - but, at the same time, has ruled out any of the West Bank concessions sought by even moderate Arabs.
One of the statement's pro-Arafat signatories, interviewed by Israeli radio Thursday, said he felt ''now is the time'' for Palestinians to ''take a stand against civilian violence. . . . We are at the crossroads of international recognition.'' He said the statement was a way ''of saying there are Palestinians who want dialogue.''
Still, prospects for a workable dialogue must depend considerably on the ongoing drama involving Arafat and President Assad.
Key will be, in Mr. Arafat's case, how and when he disengages from Tripoli. Many Arab and Western analysts continue to feel he may well prove cautious about adopting a conciliatory stand. He is thought likely to try to play for support of two harder-line Palestinian leaders - George Habash and Nayef Hawatmeh - who have stuck by him during the war with Syrian-backed rivals.
Mr. Assad, for his part, is virtually sure to try to counter any new initiative by King Hussein or moderate Palestinians - if only because it could leave Syria isolated from the negotiating process.
But it remains unclear just how serious is an illness that hospitalized Assad last month. Damascus says the problem was appendicitis. Persistent reports within the Arab world and beyond, not independently confirmed, say he is far more seriously ill.