The negotiations to evacuate the core of the Palestine Liberation Organization (PLO) trapped in west Beirut are marking time while the search continues for where they might go.
Israeli Prime Minister Menachem Begin and his defense Minister Ariel Sharon used the lull at the weekend to try to regain the initiative subtly wrested from them over the past five weeks through the political constraints which the US has managed to apply to Israeli military superiority.
First, Mr. Begin - addressing a rally of his supporters in Tel Aviv July 17 - gave the US and the PLO a veiled ultimatum. He said they had heard from the US that negotiations to get the PLO out of Beirut would take 30 days. ''I hereby declare,'' he asserted, ''the Palestinians in Beirut haven't got 30 days.''
At the same rally, Mr. Sharon said Israel was willing to give ''each of the terrorists in Beirut immediate temporary sanctuary on condition that . . . he will quit his membership in the PLO.''
Mr. Begin had another proposal - one that simultaneously broadened the framework of present negotiations and hinted at what Israel's next step is likely to be if a settlement can be reached in Lebanon.
The Israeli Prime Minister invited King Hussein of Jordan to Jerusalem to discuss the establishment of a confederation between their two countries in an arrangement which would give Jordan an outlet on the Mediterranean with free-port facilities in Haifa.
Attractive though this may sound, King Hussein and other Arabs are virtually certain to reject the proposal out of hand. They will see in it a cunning move by Israel to force the Palestinians and the international community to accept Jordan as the desired Palestinian homeland, leaving Israel free to annex the West Bank and Gaza.
They can point to statements by Israeli Foreign Minister Yitzhak Shamir in the Spring 1982 edition of Foreign Affairs:
* ''The problem is clearly not the lack of a homeland for the Palestinian Arabs. That homeland is Trans-Jordan, or eastern Palestine'' - in other words the present Kingdom of Jordan.
* ''Israel has made it clear, at Camp David and since, that it has a claim to sovereignty over Judea, Samaria and Gaza.''
The pronouncements of Mr. Begin and Mr. Sharon at the Tel Aviv rally will catch the headlines. But they leave unchanged the basic immediate need to find a way to get the Palestinians out of Beirut.
On this difficult issue, Syria temporarily threw a wrench into the works by saying it would not take them. Now the negotiators are waiting to see if Syria can be persuaded to be more flexible when the Syrian Foreign Minister, Abdel Halim Khaddam, together with Saudi Foreign Minister Prince Saud, confers with President Reagan in the White House - a meeting tentatively set for July 20.
At first sight, Mr. Khaddam and Prince Saud are an incongruous diplomatic duo to be calling on President Reagan.
The Syrians prevented the Saudi peace plan for the Middle East from getting off the ground at the planned Arab summit in Morocco last November. Syria backs Iran - whom Saudi Arabia sees as a major threat to the stability of the Arab world - in the Gulf war against Iraq.
This may seem a dangerous self-imposed isolation on the part of Syrian President Assad. But his apparent inconsistencies and willingness to be at loggerheads with his fellow Arab leaders should be seen as part of a steady tactic. That is to be a spoiler unless those Arab leaders concede to him a role center-stage in negotiations affecting the long-term future of the Middle East.
Mr. Assad has proven himself an expert at this game in the past, when others have either written him off or believed he was at the point of being totally discredited or defeated. He presumably counts on another virtuoso recovery now after the drubbing his troops have gotten from the Israelis in Lebanon over the past six weeks.
Cynics suggest that Mr. Assad is simply waiting for a big enough subsidy from the Saudis to persuade him that it is worth his while to change his mind and provide a base for the PLO, if plans can be successfully worked out for the latter's withdrawal from west Beirut. Certainly Syria has accepted Saudi money in the past. But to assume that there is no more to Mr. Assad's game than that is naive.
In a broad perspective, there is in fact a rational basis for Saudi-Syrian cooperation to help the Palestinians now in diaspora to lay the groundwork for a political rather than a military campaign to secure a homeland for themselves in part of what was once known as Palestine.
In that cooperation there is an ironic parallel with the way in which the Zionists of the Jewish diaspora organized themselves in the first half of this century to secure the establishment of the state of Israel.
What the US and the Jews of North America were for Zionism in those days - in terms of funding, graduates, and skilled manpower - Saudi Arabia and other Arab governments of the Gulf, together with the Palestinians in diaspora there, are today for the Palestinian cause.
What the ghettos of Europe represented in those days as the main source of settlers for eventual Israel, the refugee camps of Syria (and Jordan and Lebanon) are today for the Palestinian cause.
There is another parallel. Local Palestinian communities in the Gulf states have learned how to put subtle pressure on host governments just as Zionist and pro-Israeli lobbies have been doing in other parts of the world for decades. The result in both cases is often strain, with host governments acting from political expediency rather than from spontaneous affection for Zionists or Palestinians.