A new pragmatism and urgency are creeping into Israel's efforts to extricate its invasion Army from the mire of Lebanon. An important catalyst has been this week's scrapping by the Lebanese government of its May 1983 agreement on terms for Israel's withdrawal.
Beirut's reversal, under pressure from Syria, had been long expected. But it still came as a slap in the face. It made ''official,'' as one Israeli journal put it, renewed Syrian dominance of the neighbor-state Israel invaded in June 1982.
An early Israeli withdrawal does not seem likely. Even a partial pullback, though under consideration, may be far from immediate. For one thing, Israel would like to make sure such a move does not risk the sole invasion ''victory'' that survives: the removal of Palestinian bases from the extreme south of Lebanon. The Israelis have yet to find a credible proxy force to guard that gain if and when they leave.
And the government seems intent on avoiding the impression of panic in responding to the latest unsavory news from Lebanon.
Yet no longer do Israeli officials entertain hopes of a formal peace treaty with the Lebanese.
No longer does Israel expect a sovereign Lebanese Army to move south, coordinate efforts to bar armed Palestianians from the area, and facilitate an amicable pullback of Israel's troops.
No longer does Israel explicitly link its own exit from Lebanon to the withdrawal of Syria's more than 30,000 troops there.
The talk here these days is of next-best scenarios for sorting out policy in Lebanon. And it is a measure of how far Israeli ambitions have shrunk, that officials increasingly seem open to sealing some kind of ''security'' arrangement for Lebanon in which Syria would necessarily play a major part.
This is much the set-up that existed between 1976 - when the Syrian Army entered Lebanon to end 18 months of civil war there - and the Israeli invasion. A tacit understanding, known as the ''red-line'' agreement, gave Israel pretty much free rein for air strikes against Palestinians in a roughly 15-mile border strip in south Lebanon, while Syria was understood to be the dominant military force for the rest of Lebanon. Within this framework, the Israelis and Syrians took care to leave each other alone.
On the eve of Beirut's nixing of the Lebanon-Israel accord, Interior Minister Yosef Burg captured the spirit of the moment:
''It is not the paper which matters,'' he told Israeli radio, ''but the situation'' on the ground. ''And the situation is that we need security arrangements.''
''With Syria, or with Lebanon?'' he was asked.
His reply: ''Whoever can increase security is welcome.''
Defense Minister Moshe Arens, touring Israeli positions in the south Lebanese city of Sidon Tuesday, placed greater emphasis on forming a ''local'' force to ''remove part of the (security) burden'' from the Israeli Army.
But there seem to be two assumptions increasingly pervading statements by Mr. Arens and other officials:
One, the sooner the Israeli Army can reduce its profile in south Lebanon, the better. Attacks and ambushes on the force have become a nearly daily occurrence there.
Two, it is a time for pragmatism in considering arrangements to allow such a pullback.
This sense of pragmatism has gathered force since last November's suicide truck-bomb attack on an Israeli Army barracks in south Lebanon. Premier Yitzhak Shamir in effect rang in the new approach by saying that Israel would accept a role for United Nations forces in keeping the peace in Lebanon.
One rationale for the 1982 invasion was that the UN force in south Lebanon was at best useless in ensuring Israel's security, and at worst a tacit ally in the Palestinians' ''threat'' to northern Israel.
Mr. Arens, meanwhile, has made his own contribution to a revisionist Israeli reading of events in Lebanon. He says, among other things, that the Israelis must ''make every effort'' to cultivate south Lebanon's majority Shiite Muslim community.
Israel did seek dialogue with the southern Shiites after invading, but a far greater emphasis on ties with Israeli-armed Christian militiamen helped doom prospects of any workable local security force early in the process.
The tenor of recent remarks from Arens and others is that Israel now envisages a decidedly greater weight for the Shiites.
One Israeli Cabinet minister remarked this week: ''In retrospect, it seems to me it was a mistake that we didn't consider the political steps of our involvement in Lebanon.
''We concentrated only on the military aspect. Today, it's clear that the political steps are what determine matters. . . . ''