PLO's choice: gun or olive branch

Yasser Arafat and his guerrilla backers have been ousted from their last military base near Israel, issuing hollow-sounding cries of victory. They gave no clear signal of their next move in the Middle East.

The main issue facing the chief of the Palestine Liberation Organization as he left Lebanon Tuesday was - to borrow an Arafat metaphor from the 1970s - whether to holster the Palestinian gun in favor of an olive branch.

The evacuation was supposed to have been orchestrated as a triumph, like the PLO's earlier ouster from Beirut after Israel invaded Lebanon last year. Israel, after all, had failed in its bid militarily to eliminate the PLO altogether.

But under military pressure this time from Israel and from Syrian-supported rival Palestinians, Arafat left in a strikingly different manner. Boarding his evacuation ship, he resisted even his by-now-automatic impulse to play to the world news media. He left saying not so much as a word to a battalion of nearby reporters.

The evacuation was to have happened Monday. But Israeli gunboats opened up with the latest in a week-long series of shell salvos, forcing postponement of the operation.

When it finally did go ahead on Tuesday, five Greek boats protected by French air and naval forces released Arafat and some 4,000 followers and their families from a six-week entrapment in the north Lebanese city of Tripoli.

Israeli jets circled overhead. But a stern message from the US, Israel's chief ally and aid patron, evidently prodded them to abandon the intermittent naval shelling of the Tripoli and allow Arafat's forces to leave unhindered.

As truckload after truckload of fighters approached the port area, they flashed ''V for victory'' signs. Guns and grenade launchers fired into the air, echoing the deafening celebration that accompanied last year's departure from Israeli-besieged Beirut.

But fighters and their families were straightforward in voicing sorrows and concerns that lay beyond the celebration. This time, one explained, the PLO was escaping not Israel, but fellow Arabs. This time the PLO's absence from Lebanon - the last Arafat military base in a state bordering Israel - might be longer and more definitive. For it was Syria that helped reinfiltrate Palestinians into Lebanon after last year's evacuation.

Arafat and his aides offered only vague indications of the PLO chief's future plans. Where would he travel in the near future? Tunisia . . . Yemen . . . maybe Egypt. Asked that question by one reporter on the eve of the departure, Arafat went so far as to reply: ''Palestine.''

Arafat's itinerary may provide the first indication of whether he intends a major shift from gun to olive branch. Trips to moderate Jordan or Egypt could be important signals.

But at least for now, Arafat seems to have fallen back on a familiar impulse: to decide not to decide, in hopes of somehow securing the best of both gun and olive branch - or at least avoiding a definitive break with backers of either line in the PLO.

He hinted at a resumption of talks with Jordan's King Hussein that had floundered last spring. But Arafat also stressed that he remains inclined to resist the King's idea that the talks should seek to activate President Reagan's blueprint for a peace with Israel.

And statements at the height of last month's military offensive by the rebels against Arafat suggested he may also want to court key Palestinian hard-liners who refused to join the PLO mutiny.

If Arafat does take this tack, he may do so partly because of a strong feeling among many in the Arab world that Israeli policy on the Palestinians makes a diplomatic resolution of the Mideast crisis close to impossible.

With Arafat gone, a legacy of human tragedy - Lebanese and Palestinian - remained in Tripoli.

Even as the evacuation progressed, Palestinian civilians could be seen walking, stooped under bundles of mattresses and other belongings, back to the Baddawi refugee camp abandoned by some residents after it became engulfed in the intra-PLO fighting.

Some Lebanese in Tripoli will miss Arafat. There is Ali, for instance, who peddled grilled cheese sandwiches near the PLO chief's headquarters. Or the suitcase salesman: The evacuation trucks presented the odd picture of new carryalls, mostly Samsonite, and rifles, mostly Soviet-manufactured AK-47s.

But many natives of Tripoli harbored bitterness toward the PLO men. The internecine war badly battered parts of the city. And Arafat's departure also raised concerns that his Syrian rivals might now move militarily to take control of the city from Muslim fundamentalist militants who had fought alongside Arafat's forces.