A year after bowing to superior Israeli might and abandoning their capital-in-exile of Beirut, the men of Yasser Arafat's Palestine Liberation Organization fear another military siege may be in the planning to try to dislodge them from this new PLO bastion in northern Lebanon.

This time the expected enemy is not the Israeli Army that pushed them out of Beirut, but fellow Arabs from the Syrian Army of President Hafez Assad, who is locked in a bitter feud with Arafat over the control of the Palestinian movement.

Syria is backing a three-month-old mutiny against Arafat by dissidents in his Fatah organization in the Syrian-dominated Bekaa Valley of Lebanon southeast of here.

Thus the possibility of a Syrian siege against the PLO, which is dug in around this refugee camp on the outskirts of the northern Lebanese port of Tripoli, clearly troubles Arafat loyalists who are determined their movement will remain independent of Syrian control.

A visitor fresh from Damascus, the Syrian capital, is repeatedly questioned about Assad's intentions now that the mutiny led by Col. Said Abu Musa seems to have stalled. Although the Syrians--who Arab and foreign analysts are increasingly convinced inspired the mutiny--had counted on a bandwagon movement rallying behind the mutineers, it has become clear that this has not happened.

Abu Musa's revolt continues because of Syrian military protection and support, the open involvement of Syrian-directed Palestinian splinter groups and what is estimated to be a battalion of Libyan soldiers under Syrian command in the Bekaa.

"Is it possible for Assad to play the new Sharon?" asked Ahmed Abdel Rahman, the head of the PLO's information department, referring to former defense minister Ariel Sharon, the architect of last summer's Israeli siege of the Lebanese capital.

"Would Assad be prepared to make another Hama here?" he asked. This reference was to Assad's crushing last year of a Moslem fundamentalist revolt in the Syrian city of Hama where, western diplomats estimate, about 30,000 Syrians were killed by their own Army.

What prompts this sense of urgency is that Badawi has been transformed into Arafat's most important base in Lebanon, but it is within the part of Lebanon garrisoned by 40,000 Syrian soldiers.

The sight of antiaircraft guns poking out of the olive groves that surround Badawi and the uniformed guerrillas who ply its dusty, pot-holed streets with Soviet-made Kalashnikov assault rifles slung casually from their shoulders reminds one of the PLO's period of power in Beirut's Fakhani district before Israel's punishing 2 1/2-month siege forced them to leave.

It is evident in a visit here that Abu Musa's rebellion has little support among the people of Badawi. There is hardly an earthen wall that does not bear a half-dozen stenciled silhouettes of Arafat's bearded visage or posters extolling him by his nom de guerre of Abu Ammar.

One slogan says: "You can take Abu Ammar from our homes but you cannot take Abu Ammar from our hearts." It refers to Assad's expulsion of Arafat from Syria in June after the PLO leader publicly attacked Syria for its support of Abu Musa. The expulsion has also effectively kept Arafat from Badawi and other parts of Lebanon under Syrian control.

Arafat's absence has not reduced the importance of Badawi, which has become the nerve center for his efforts to counter the Syrian-guided challenge to his leadership of the Palestinian movement. The transmitters of the PLO radio station Voice of the Palestine Revolution and the printing presses for the PLO newspaper are here and the camp also has become the headquarters of Khalil Wazir, also known as Abu Jihad, Arafat's equivalent of a defense minister.

Abu Jihad, a loyalist much respected among Palestinians for his organization of the first guerrilla raids against Israel in the 1950s, now is Arafat's surrogate in Lebanon, charged with ending the mutiny that has tarnished the PLO's credibility and brought its political power into question.

Like most of the Palestinian leaders one meets in Arab capitals and in the Israeli-occupied territories of the West Bank and Gaza, Abu Jihad is in despair over the mutiny that erupted in May with calls for "reforms" within Fatah--the largest faction in the PLO and Arafat's power base--including an end to the "autocracy" of Arafat's rule and a return to democratic dialogue within the organization.

"Everyone is very sad about what is going on," Abu Jihad said in an interview. The mutiny "is an open wound we are suffering that has turned us away from our basic aim of struggling against Israel for a Palestinian homeland."

Abu Jihad said that the reforms Abu Musa claimed he was fighting for had already been under debate within Fatah when the rebellion broke out and that many of them have since been implemented without the rebels even acknowledging them.

The fact that the rebels have not responded to the reforms or to mediation efforts, Abu Jihad claimed, was proof that they were not revolting for the reasons they claimed but because they were being encouraged by Assad, who has long opposed Arafat and sought to control the PLO.

In addition to its problems with Israel, Abu Jihad said, "now obstacles to our struggle are being erected by other Arabs"--he made clear he meant Syria and Libya--"who created, promoted and supported" Abu Musa's revolt.

While reports conflict on the extent of the mutiny, it is clear it has gathered few new Palestinian adherents since its first month and no senior Fatah officials or military commanders beyond the handful who were with Abu Musa at the beginning.

What military successes Abu Musa's men have had in their frequent battles with Arafat loyalists in the Bekaa, Arab and western analysts agree, are the result of Syrian support rather than his own strength.

Politically, Abu Musa is isolated. He has failed to rally support within either the councils of the PLO or Fatah.

Arafat, on the other hand, has succeeded in demonstrating that the Palestinian movement--including many who agree with some of the rebels' criticisms--remains behind him. He has received expressions of support from leading Palestinian groups around the Arab world, including important endorsements from leaders in the Israeli-occupied territories.

Even such old rivals and ideological challengers as George Habbash of the radical Popular Front for the Liberation of Palestine and Marxist Nayef Hawatmeh have quietly indicated their opposition to the mutiny and their continued backing of Arafat's insistence on keeping their movement independent of Arab regimes that would like to use it for their own purposes.

The most important confirmation of support for Arafat came in Tunis a week ago at a meeting of the PLO's broad-based Central Council, convened by Arafat to discuss the issue. Of the 81 members, only the two representatives of the Syrian-run Front for the Liberation of Palestine-General Command group of Ahmed Jebril boycotted the session, which endorsed Arafat's call for unity and formed a committee to try to talk to the rebels and the Syrians.

Abu Musa and his group acknowledged their weak position before the council even met by stating publicly that they would ignore any resolutions that came out of it.

Even if Arafat continues to hold the PLO majority, however, Syrian backing of Abu Musa is still a grave threat to his overall power. Through Abu Musa, Syria has created a perception of dissension in PLO ranks and, more importantly, has shown the inability of Arafat's men to counter a military challenge guided by the Syrians.

Arafat and his men know that their movement's political clout has always depended on the perceived military clout of its fighters.

As Arafat said in 1968, as long as Palestinians were viewed as mere refugees waiting around for U.N. food rations, "nobody was likely to respect them." It was only when Palestinians began to carry rifles that "the situation changed."

If Assad can gain control of those rifles--or neutralize them by isolating them from the confrontation lines with Israel--Arafat, according to associates, knows he could lose much of the political influence he has worked so hard to build up in his 14 years as the chief of the PLO.

That is what senior PLO leaders believe Assad wants. For while his dispute with Arafat is primarily personal--going back two decades--it is also strategic.

Senior PLO officials interviewed in Tunis, Damascus and here in Badawi, as well as Palestinian leaders on the occupied West Bank, see Assad trying to gain control of the PLO so he can use it as a bargaining chip in any future negotiations on the Middle East. Assad, these sources say, has always wanted to be the key man in such negotiations.

If he fails to gain outright political domination of the PLO, Arafat's loyalists fear, Assad could try to crush them militarily here. Or, if he fears Arab reaction to such an act, he could still gain great leverage in the area by controlling the confrontation lines with Israel with a chosen Palestinian like Abu Musa--much as the Israelies have used cashiered Lebanese Army major Said Haddad to do their bidding in southern Lebanon.

This, PLO leaders say, would formalize the de facto partition of Lebanon between Israel and Syria and neutralize the vast majority of the PLO military units that remain loyal to Arafat in Lebanon.

Despite Arafat's political support among Palestinians at large and the many Arab and nonaligned efforts to mediate a rapprochement between Arafat and Assad, PLO leaders like Abu Jihad acknowledge that there can be no solution to the crisis so long as Syria does not want one.

"The future depends first of all on the Syrian stand," Abu Jihad said. "The responsibility for what happens next is in their hands, not ours. We hope we can solve the problems between us and our Syrian brothers because if not our wound will deepen and the whole Arab world will suffer for it."