Beirut — A peaceful end to the bloodshed in Lebanon again seems to be slipping through the fingers of diplomats. And because both Israel and the Palestine Liberation Organization are sure of their strengths, more fighting seems likely.
''I look here and there and see the devastation and am much more pessimistic, '' Walid Jumblatt, influential leader of the Lebanese National Movement, said Aug. 2 as he surveyed the hard-hit Fakhani neighborhood of west Beirut, where the PLO makes its headquarters. This was the morning after 14 hours of relentless Israeli bombing and shelling.
''I am afraid,'' said Mr. Jumblatt, ''that Lebanon will be destroyed.''
Mr. Jumblatt's feelings were echoed by PLO official spokesman Mahmoud Labadi as he stood in the glass- and rubble-strewn street in front of his office. ''They compare this with Stalingrad. I tell you it is much worse . . . but what can we do but resist?''
Mr. Labadi, who along with thousands of other Beirutis spent Aug. 1 in bomb shelters, characterized the Israeli pounding as ''a continuous war against the peoples of Palestine and Lebanon.''
And it seems far from finished:
* A cease-fire was regularly being broken Aug. 2.
* Hundreds of Israeli tanks and armored vehicles were massing around west Beirut.
* Efforts to bring in United Nations troops to monitor the latest cease-fire were being frustrated by Israeli reticence.
* And the PLO, while reporting itself still willing to leave west Beirut, now explicitly says it will not leave Lebanon immediately.
The latest cease-fire, the ninth since June 6, might have been bolstered by UN supervision. But Israeli officials seemed to stall on this, saying they could not bring in the UN without a full Cabinet decision. They then made no attempt to convene the Cabinet and with Foreign Minister Yitzhak Shamir in Washington such a meeting was unlikely.
Even though the city still stood Aug. 2 after what newspapers here called ''black Sunday,'' it was much worse for wear - and guns were booming ominously in the southern suburbs. The emergency continued even if the fires had been extinguished.
A diplomatic way out looked unpromising. This was because the PLO, the Lebanese central government, the Israelis, and the Lebanese rightists were far from agreement on what they were talking about. This left the key mediator, US envoy Philip C. Habib, to try to build peace on ever-shifting sands.
Mr. Habib has been under pressure from Israeli leaders to get an unequivocal statement from the PLO about leaving all of Lebanon. And the rightist Lebanese Phalange does not want the PLO in Beirut, even in a token manner, and objects strongly to its moving to other parts of the country except in transit out of Lebanon quickly and completely. The Lebanese central government, meanwhile, speaks with pro- and anti-PLO voices.
The PLO is not willing to leave Lebanon altogether and without condition, PLO central committee member Hani Hassan said Aug. 2. It is willing to leave west Beirut, but only in stages with guaranteed safe passage to northern and eastern Lebanon. And then only some of the fighers - not all fighters and leaders as Israel's Menachem Begin has been demanding - are prepared to go.
''We have never discussed and Mr. Habib has never spoken about all of Lebanon , only west Beirut,'' Mr. Hassan said. ''For a week we have been waiting for an answer on our proposal (a timetable for vacating west Beirut which also calls for an Israeli pullback from the capital area) from Mr. Habib, and we have received no response.''
Mr. Labadi believes the Israelis ''are blocking all kinds of negotiations because they just want to crush the PLO.''
Of primary concern Aug. 2 was the shaky military situation here. The massing of Israeli tanks could have been a prelude to another attempt to advance on Palestinian positions in and around west Beirut. Or it might have been a psychological ploy designed to intimidate the PLO. Either way, it seemed a dangerous sign.
The extended shelling and bombing Aug. 1 ruined much of west Beirut. Some reports said 180,000 shells were fired and the Israelis flew 200 bombing sorties. According to Lebanese authorities, 165 persons were killed and 400 injured. This was through no special Israeli precautions, rather through the war experience residents of Beirut have.
Throughout the west side, and at the crossing points between west and east, families were loading up possessions and leaving their homes for refuge elsewhere in the country.