The announcement that Israeli and Lebanese Army officers will begin talks Monday on an Israeli withdrawal from south Lebanon is a bittersweet victory for Israel.
Bitter, because the structure and location of the talks are a sharp reminder of how dramatically Israel's position in Lebanon has eroded and of how Syria's position has been enhanced since Israel invaded in June 1982.
Sweet, because this is a concrete step toward ending an occupation that has cost the Israelis dearly in lives, money, international prestige, and internal morale.
There is no guarantee that the talks will result in an agreement between the two parties. Israeli Foreign Ministry officials insisted Thursday that neither the agenda nor the composition of the delegations has yet been agreed on, and one official predicted that the talks initially will consist of arguments over what to talk about.
But the scheduling of talks after months of stalemate is progress. The breakthrough came after two weeks of intense shuttle diplomacy by Jean-Claude Aime, assistant to United Nations Undersecretary General Brian Urquhart.
Mr. Aime arrived in Jerusalem Sept. 15 and has traveled to Beirut as well as to Damascus, Syria, and Amman, Jordan, seeking an agreement to start direct negotiations.
The announcement that talks would be held at the headquarters of the UN Interim Force in Lebanon (UNIFIL) in Naqurah, south Lebanon, was made at the United Nations in New York Wednesday.
''We were very pleased to hear that direct military talks are going to be held,'' an Israeli Foreign Ministry official said Thursday in Jerusalem.
But the official, who spoke on condition his name not be used, acknowledged that these talks will contrast sharply with those that took place between the Israelis and the Lebanese in the spring of 1983.
The earlier talks were held on a political level. They alternated between Khalde, Lebanon, and Kiryat Shemona in Israel. The United States was an active participant and cosignator, and Syria was excluded by all parties.
The Israelis succeeded in getting the Lebanese to sign a political agreement, but their achievement soon evaporated. The so-called May 17 agreement was never implemented. In the face of adamant Syrian opposition, the Lebanese abrogated it nine months after it was signed. Last June, the Israelis removed their last vestige of an official political presence in Lebanon when they closed their political liaison office south of Beirut.
Its hopes of achieving a political victory as the result of its invasion of Lebanon dashed, Israel began to explore ways of securing an arrangement with Syria and Lebanon that would trade an Israeli withdrawal for guarantees that Palestinian guerrillas would be prevented from threatening Israel's northern border area.
(On Thursday Syria gave its approval of the talks, but said it would not guarantee the security of Israel's nothern border, Reuters reported.)
Some 15,000 Israeli troops remain deployed as far north as the Awali River, just north of Sidon, the major city in southern Lebanon. They are directly confronting the Syrians in the Bekaa Valley to the east.
The first indication that a new round of talks on an Israeli pullout from south Lebanon might begin came in September, when United States Undersecretary of State Richard Murphy flew to Beirut after the bombing of the American Embassy annex in east Beirut.
Mr. Murphy's visit turned into a round of shuttle diplomacy. He flew to Damascus, Amman, Jerusalem, and Cairo before returning to the US.
But the Reagan administration, unwilling to tackle a process as frought with potential failure as Israeli-Lebanese negotiations before the presidential elections, seems willing to let the UN play the role of mediator this time.
The US's chief concern, at this stage, seems to be working behind the scenes to see to it that Syria not be excluded this time.
Murphy is again in the Middle East. He was in Jerusalem Thursday and said the United States ''was delighted by yesterday's news that talks are about to start.'' The undersecretary is expected to visit Arab capitals again before returning to Washington.
The public role of broker, however, seems clearly to have passed to the UN. This is due partly to the fact that the Israelis have said they want a greatly expanded UNIFIL force to take over many of the security chores in the south if Israel pulls out.
The Israelis have stressed that the talks will be held under UN auspices but will not be chaired by the UN.
That issue became a sticking point between the Israelis and the Lebanese in the last two weeks. The Lebanese wanted the talks to be held within the framework of the 1949 armistice agreement signed between Israel and Lebanon under UN auspices on the island of Rhodes.
The Israelis insisted that the talks not be held within the armistice framework. The Israeli Foreign Ministry official said Thursday that Israel had won that point.
The official also said Israel is confident that this time, ''if the Lebanese government is in talks with us, they do that this time at least with a prior Syrian understanding or green light. So what happened last time can't happen again.''
Monitor correspondent Louis Wiznitzer reports from the UN:
UN officials expect the Israeli withdrawal to take place in three phases:
1. Back to the Zahrani River, and out of the western Bekaa Valley.
2. Back to the Litani River.
3. In the distant future, to the Lebanese-Israeli border.
As the Israeli troops withdraw, UN officials expect UNIFIL to be deployed in the areas evacuated by Israel.