Tunis, Tunisia — The Palestine Liberation Organization appears to have decided to stay the course. Next week's long-awaited meeting in Algiers of the Palestine National Council (PNC) - the first gathering of the PLO's highest policy-making body since the Israeli invasion of Lebanon - is not expected to change drastically the PLO's current cautious posture.
But Palestinian moderates warn that a radical swing toward military confrontation is inevitable if the West, and particularly the United States, does not recognize the Palestinian right to self-determination.
After months of internal debate on the lessons of Israel's invasion of Lebanon and the merits of President Reagan's call for Palestinian self-rule in association with Jordan, and a series of high-level negotiations between Jordan and the PLO, Palestinian officials feel that time is running out.
These officials argue that US and West European policies are narrowing their options, redirecting Palestinian thinking toward revolutionary tactics instead of diplomatic initiatives.
''We are about to come to the end of the diplomatic road if this situation continues,'' warns Khaled Hassan, a close aide to Yasser Arafat and chairman of the PNC foreign relations committee.
According to ranking PLO officials, the PNC in Algiers will issue a final statement reaffirming past PNC resolutions and the Arab peace plan adopted at last September's Arab summit conference in Fez.
The PNC resolutions call for the establishment of an independent Palestinian state ''in any part of Palestine which is liberated or from which Israel withdraws.'' The Arab peace plan goes one step further by calling on the United Nations Security Council to guarantee peace ''among all states in the region,'' including Israel.
The PLO's reluctance to recognize explicitly Israel's existence is in part the result of strong Syrian opposition against further Palestinian moves toward moderation and toward accommodation of Jordan, Egypt, and the US.
In an effort to maintain Palestinian unity, PLO Chief Yasser Arafat agreed not to adopt a new, more moderate political program at the Algiers meeting. In exchange for this, the pro-Syrian Palestinian organizations are expected to participate in the coming PNC discussions.
Nonetheless, PLO officials stress that both the PNC resolutions and the Arab peace plan recognize Israel.
''Of course Israel is included'' in the Arab peace plan, said Mr. Hassan.
''When we agreed to have a state in a part of Palestine, when Arafat said that the Palestine National Council has accepted all United Nations resolutions related to the Palestinian problem, that includes partition, that includes two states in one country. . . .''
In an interview here Mr. Arafat said, ''We, the Arabs, have offered this Arab peace plan because we are willing to find a peaceful solution and a lasting solution and a comprehensive solution in this area.''
Asked if the Arab call for security for all states in the Middle East includes Israel, Mr. Arafat replied: ''It is clear and obvious. In spite of this it was not accepted by the Americans and completely rejected by the Israelis.''
Mr. Arafat added that ''we are ready to establish our independent state in any part of Palestine from which Israel withdraws.''
The PLO chief went on to say that he will ''definitely'' put down his gun once the Palestinian state has been established. ''I want to return to work as a civil engineer.''
PLO officials feel, however, that the West deliberately ignores the manifestations of their willingness to compromise.
''We feel deserted,'' said Mr. Hassan, who also serves as one of the PLO's senior envoys to the West. ''The West understands what we are offering,'' he added, ''but prefers to pretend that it does not understand it. The West simply does not want to recognize the Palestinians as a people.''
Bitterness over events in Lebanon, Mr. Hassan went on to say, is furthering radicalism in the Middle East. ''We can't stop it any more because we failed to realize our hopes through peaceful and political thinking.''
PLO officials predict that the new radicalism - a combination of Arab, Palestinian, and Muslim extremism - will be directed primarily against Arab governments and established Arab political parties.
''We only have one option left to us: revolutionary tactics,'' Mr. Hassan said. He added with a deeply unhappy expression on his face: ''This means violence until success. Possibly then something else will develop, I don't know.''