The indefatigable Philip Habib has plunged into new negotiations here. His aim: removal of all foreign troops from Lebanon.
Some Lebanese press reports, exuding optimism, say the United States envoy has set Christmas as a goal for completing the withdrawal of Syrian, Palestine Liberation Organization, and Israeli forces from the country. Such a goal is neither denied nor confirmed by American sources.
Informed sources do say, however, that Mr. Habib stressed emphatically the need for speedy negotiations when he met with Lebanese President Amin Gemayel on Friday. It will be necessary to move fast, he believes, in order to maintain the momentum generated by the evacuation of PLO fighters from Beirut in August and the Israeli withdrawal from the Lebanese capital last week.
Sources here stress there has as yet been no concrete agreement by the three parties involved on a timetable for withdrawal. Much of the optimism here, they say, has been generated by Syrian willingness to remove its troops from Lebanon.
When Mr. Habib this weekend met in Damascus with President Assad and other Syrian officials, they reportedly repeated to him the message conveyed by Syrian Foreign Minister Abdel Halim Khaddam in New York to US Secretary of State George Shultz: The Syrians are willing to leave on the request of the Lebanese government - on condition that Israeli troops leave Lebanon.
''The Syrians want Israel out of Lebanon, and they can't drive them out without getting beaten,'' said an analyst here. ''So the only way to get them out is by a Syrian withdrawal.''
Israeli officials have also assured the Americans repeatedly that they want to withdraw their troops from Lebanon. However, Mr. Habib confronts a tricky juggling act in trying to balance the price and the timing that each of the three foreign forces wants for its departure:
* The Syrians are saying they want Israeli troops to withdraw first. Moreover , a resolution by the Arab summit conference in Fez, Morocco, in September left Syrian evacuation to be negoated between Damascus and Beirut. This angered the Lebanese authorities, who have no interest in negotiating with Syria over an Arab League-authorized mandate for a Syrian protective troop presence of 30,000 that formally expired last July. This problem could be eased by the favorable Syrian reaction to new Lebanese President Amin Gemayel, whose late brother, the murdered President-elect Bashir, they bitterly opposed.
* The Palestinians. The Syrians say they are not responsible for the PLO presence of some l0,000 men in north and east Lebanon, where Syrian troops are also based. Palestinian sources here say moderate Palestinian leadership will seek some form of recognition by the US in return for leaving, while more radical Palestinians may refuse to quit Lebanon.
* The Israelis, according to the well-informed Tel Aviv daily, Ha'aretz, are demanding that the PLO pull out first, to be followed by a simultaneous Syrian and Israeli withdrawal. The Israelis also have indicated that unless they get a peace treaty from Lebanon, they will insist on maintaining control of a security zone 50 kms (30 miles) north of Israel's border into Lebanon via the forces of their Israeli-funded and armed Lebanese Christian ally, Maj. Saad Haddad.
Both President Amin Gemayel and the US government are known to oppose the idea of such a separate enclave. This could pit them together against Israel on this issue.
Israel is likely to bargain stiffly to maintain the presence it feels is necessary for Israeli security. One indication was negotiations over Israeli evacuation from Beirut International Airport, where Israeli insistence on maintaining some physical presence there necessitated last-minute pressure from Washington, according to reliable sources here. Israel retained only the right to use the airport in emergency situations with Lebanese government permission.
At time of writing, negotiations were continuing between Israel and the Lebanese government over Israeli withdrawal from Baabda, seat of the Lebanese presidency, where Israel wants to maintain some form of Foreign Ministry and information presence. The Lebanese press has described these demands as an Israeli attempt to maintain some sort of normalized relations with the Lebanese state.
Mr. Habib is said by Lebanese sources to be thinking in terms of staged simultaneous withdrawal by the three parties that would be supervised either by the Lebanese Army, or, if that were not feasible, by a United Nations or international force.
Time is also an important factor in the presence here of l,200 US marines, part of a multinational force helping the Lebanese government to reestablish order and authority. Their presence, along with the French and Italian troops, is a key psychological booster to the reviving Lebanese Army.
A withdrawal before Lebanon is free of foreign forces could be extremely damaging to US credibility and Lebanese optimism, especially since many Lebanese think the first peacekeeping force sent to oversee the PLO evacuation was withdrawn prematurely. But if the negotiating over withdrawal of all foreign troops drags on interminably, President Reagan could face domestic pressure to bring the boys home.