Partition of Lebanon or a move toward total withdrawal of Israeli troops? Israel's imminent partial troop pullback from Lebanon is given the latter description by government officials here.
But its practical meaning could be the long-term division of Lebanon.
There is little optimism in Jerusalem about the prospects of the mission of Robert McFarlane, the United States special envoy who is scheduled to visit Damascus later this week. His trip is part of a Mideast mission aimed at unblocking Syrian opposition to the Israel-Lebanon security accord on withdrawal of Israeli troops from Lebanon.
Israel will not pull back totally unless 40,000 Syrian troops, along with those of the Palestine Liberation Organization, also leave Lebanon. But the Lebanese government fears its country will be permanently split into Israeli- and Syrian-controlled areas with the government ruling little more than Beirut.
On his return from Washington, Foreign Minister Yitzhak Shamir told the Israeli Cabinet that Syria apparently had no intention of withdrawing its troops from Lebanon and that Israel had no idea what proposal Mr. McFarlane would present in Damascus. The foreign minister said that the US administration had aired the idea of a separation of forces between Syrian and Israeli soldiers, now face to face in eastern Lebanon's Bekaa Valley, and that Israel did not reject this idea in principle.
It is understood here that Mr. McFarlane would welcome a Syrian demand, if made, for a separate Syria-Lebanon security agreement not linked in any way to the Israel-Lebanon accord. Then the US administration would try to convince Syria to incorporate a withdrawal timetable in such an agreement and would approach Israel to submit its own timetable.
But Damascus continues to trumpet its vows to stay put in Lebanon unless the Israel-Lebanon accord is abrogated. In a letter to his troops on Armed Forces Day on Monday, Sryian President Hafez Assad said Syria would ''foil all surrenderists schemes, particularly the contract of submission,'' a Syrian term for the Israel-Lebanon accord.
As for Israel, officials here insist that the US has not asked Israel to draw up any final withdrawal timetable, but is making do with top-level assurances that Israeli redeployment to the Awali River, 27 miles north of the Israeli border, constitutes the first stage in a comprehensive withdrawal.
In the meantime, however, the outline of Israel's future defense position is emerging, along with many questions about its degree of permanence.
Israel will evacuate about 90 square miles including Beirut suburbs and the Shouf Mountain region east of Beirut. The new lines will follow the Awali River in the west and center of Lebanon. In eastern Lebanon, however, Israeli forces will keep their current positions, staying within firing range of the strategic Beirut-Damascus highway and atop the important mountain peak of Jebel Barouk.
An estimated 600,000 people will remain under Israeli control, predominantly Shiite Muslims, but including the Sunni Muslim city of Sidon with a population of 150,000.
One key question, still unanswered, is the nature of the new defense perimeter along the Awali. Some analysts speak of the need for a security fence system along the Awali like that which Israel has built in the Jordan River Valley bordering the Hashemite Kingdom of Jordan. This system includes electric early-warning devices, mines, and specially monitored roads for detecting infiltrators. In Lebanon, which, unlike the Jordan Valley, would have a large population adjacent to the fence on both sides, there would have to be well-guarded transit points through which civilians could cross from north to south Lebanon and back.
Such a system, designed to cut down on Israeli military casualties by controlling infiltration into south Lebanon by anti-Israeli guerrillas, would - if instituted - separate south Lebanon from the Beirut region.
While some Israeli military sources talk of a fence system as a possibility, one senior military source insists it will not be necessary. The new lines ''don't mean electric fences or a line of fortification,'' this source said. ''There will be a line of observation posts (along the Awali) and military patrols connecting them.'' The military source said this will suffice because the topographic features of the new lines will be better suited for protection and defense of Israeli soldiers.
Journalists traveling along the Awali have seen no signs yet of construction of fences or outposts. Chief Israeli Ordnance Officer Brig. Gen. Rami Dotan has said that the Israeli Army does not intend to establish permanent bases on the new deployment line in Lebanon.
However, Israel has recently been making efforts to exert control over feuding Lebanese ethnic groups within the south, apparently to smooth the way for its stay there.