Israeli Army pressing at the gates of Beirut, more confident in military option than diplomacy

The Israeli military did not share the widespread confidence Aug. 9 that the diplomatic solution for getting the Palestine Liberation Organization out of west Beirut had emerged.

In fact, the Israeli Army pushed farther into west Beirut and kept up its cannonading of Palestinian refugee camps in the city's southern suburbs even as diplomats discussed the final details of the settlement. This plan was understood to call for the majority of the Palestinian guerrillas in west Beirut to be evacuated, for a multinational peace-keeping force to enter the Lebanese capital, and for the balance of the guerrillas then to depart.

''We are ready for the west Beirut operation if we get the order,'' Israeli Col. Yehiel Ben Zvi told the Monitor. ''We can pick up the proper file on the proper operation and go.''

Colonel Zvi, Israel's official military sopkesman in Lebanon (and in civilian life the vice-president of Tel Aviv University), said he did not understand how his government could agree to United States envoy Philip C. Habib's plan for the phased evacuation of the PLO.

''How will we know who is staying and who is leaving of the 6,000 to 8,000 Palestinian guerrillas?'' the colonel asked. ''And we have had very bad experiences with buffer forces in the past when they are controlled by other nations that are not parties to the situation.''

Colonel Zvi said the United Nations Interim Force in Lebanon (UNIFIL) was an example of a peace-keeping force that did not effectively perform its mission. He criticized the UN force for failing to deter PLO penetrations into northern Israel. He said a multinational force proposed for west Beirut would have the same problems as UNIFIL unless all guerrilla forces had been evacuated - or driven out of - the city before it arrived.

But the colonel admitted this was a situation more appropriate for diplomats to handle. ''The Israeli Defense Forces (IDF) have nothing to do with the diplomatic process. If and when the government of Israel decides that there is no diplomatic option, however, then we are ready to act.''

Of considerable concern here were reports about the Aug. 9 attack on a Jewish restaurant in Paris. It is noted that a gun attack on Israel's ambassador to Great Britain, Shlomo Argov, was the act that precipitated the long-planned invasion of Lebanon that began June 6.

Even though there technically was a ceasefire in Lebanon Aug. 9, Israeli tanks pushed forward into west Beirut at the National Museum crossing point, pressing slowly toward the Fakhani Street headquarters of the PLO. Heavy bombardment of this sector of west Beirut preceded this modest advance.

There was also Israeli shelling in the area of the Borj El Barajneh, Sabra, and Shatila refugee camps. Israeli jets carried out air strikes on Beirut as well as on alleged Palestinian positions in the Bekaa Valley.

Another form of pressure was the continued Israeli cutoff of electricity to west Beirut. Water services were restored, but lack of power prevented the pumping of water and food was in short supply.

There was a great deal of hope being placed in the diplomatic solution Mr. Habib has been working on. Israel appears to be the most reluctant party, but not everything has been cleared up. Unresolved issues include:

* The Lebanese government has generally supported the phased PLO withdrawal plan, but there has not yet been a formal request from President Elias Sarkis to France, Italy, and the United States that they form an international force (3, 000 men reportedly are needed) and send it to Lebanon.

* The right-wing Lebanese Front of east Beirut is not convinced of the wisdom of allowing any PLO officials to remain in Beirut. The Lebanese Front is seeking a clear PLO commitment that it will leave the country completely; otherwise the Lebanese Front's military arm, the Phalange, in alliance with the Israelis, still may attempt to drive the PLO out of the country by force.

* Though the PLO is reported ready to leave Beirut, PLO officials have not said they are ready to leave Lebanon altogether. But Mr. Habib's plan is thought to call for the guerrillas to be evacuated to other Arab countries. Israel and the Lebanese Front object to the moving of the PLO to another part of Lebanon. Moreover, hard-liners in the PLO have not backtracked on earlier statements that they prefer to stay and fight ''street to street, house to house.''

* And the Arab countries to which the PLO fighters presumably would be evacuated are a bit fuzzy on whether they will actually welcome them. Egypt and the Sudan say they will accept some guerillas only if it is understood that this is part of a wider settlement of the Palestine problem. Syria is still very reluctant, the last official word from Damascus to the PLO being advice to fight to the death. Only Jordan has expressed willingness to accept guerrillas, but these must be current holders of Jordanian passports and must not have criminal records. Mr. Habib's efforts in this area are concentrated on trying to win a commitment from Syria that it will, in fact, sponsor Palestinian evacuees.

These unresolved problems, Colonel Zvi says, mean that diplomats ''haven't reached the stage where they are planning the exact process and procedures for a withdrawal.'' That is why he is pessimistic. And this pessimism is reflected in the unceasing pressure the Israeli Army is putting on west Beirut.