Block by block, the United States appears to be successfully erecting a framework for renewed negotiations over the West Bank. The Israelis are not happy with President Reagan's Sept. 1 peace plan, but at least are willing to resume the Palestinian autonomy talks. Most important, the Arabs are beginning to understand that, with the US now deeply committed to the peace process, this is a rare opportunity to save the territory for Palestinians before it is gobbled up by the Israeli occupiers and all chance of a negotiated settlement is lost. They are right.
King Hassan of Morocco added the latest encouraging note when, speaking on behalf of the Arab League after a visit to Washington, he said that the Arab nations ''want to live in peace with Israel.'' To be sure, the monarch went on to qualify that there would be no recognition of Israel until it surrendered the lands seized in the 1967 war - West Bank, Golan Heights, and the Gaza strip. But he gave an even more forthcoming assurance from the Arabs than emerged from the recent Arab summit in Fez:
''When we establish these borders on the basis of the pre-1967 situation, we must say these are the borders of Israel. We must say it undeniably. Israel then can say that it is living in peace with security.''
How to translate these improving atmospherics into bargaining at the negotiating table is now the key question. Much depends on whether King Hussein of Jordan will join the talks (inasmuch as Israel will not talk with the PLO). That depends, in turn, on whether the Palestine Liberation Organization will give him the green light to do so. An early occasion for this could come at the meeting of the Palestine National Council (the PLO-dominated parliament-in-exile) expected to take place later this year.
It has been said often, but should be said again. The hour is growing late when the Arab leaders, and above all the PLO, can remain aloof from the peace process. They risk what political capital they now have if they do not turn it into the hard currency of diplomatic gain. They have the ear and attention of the American President. They have the good will of the American people. They have worldwide sympathy for the plight of the Palestinians.
But much of this could be lost if public opinion perceives that PLO leader Yasser Arafat is not prepared to be flexible and to take advantage of the diplomatic window open to him.
In fairness, it should be added that Mr. Arafat and his Arab colleagues have a legitimate concern, and that is the ongoing Israeli absorption of the West Bank. Washington can greatly strengthen its own hand by being firm with Israel regarding any new settlement activity - firmness that obviously will have to be more than rhetorical disapproval. This is not to ignore the remaining problems in Lebanon requiring urgent attention. But, if the US hopes to nudge the Arabs into sitting down and negotiating, it may have to make sure there is something to negotiate about.