THERE IS a glimmer of hope out of the gloom of Lebanon. It is not simply that Aerican shuttle diplomacy, conducted by Philip Habib, has helped Syria and Israel avoid war so far. It is that some of the parties, Lebanese and foreign, give signs of using the time thus bought to work on the underlying problem of the fractures within Lebanon. Since the terrible civil war of 1975-76, the situation in that poor country has been forzen at the good moments and otherwise deteriorating. The possibility emerges, however, that the ocntext was one in which things had to get even worse before they could get better. They got worse in April. In May . . .

Let's evade that question for a moment, and double back to Mr. Habib. His purpose has been to deal only with the "immediate" Israeli-Syrian issue. The first requirement is to find a face-saving way for Syria to take out the missiles it moved into the Bekaa valley. The solution being talked of, in print anyway, entails introducing Lebanese troops into positions occupied in their shoving match last month by Christian Phalangists and Syrians. Lebanese troops would presumably not meed a missile defense, so the missiles could be withdrawn. That would let Israel stand down.

Syria has drawn fair value -- restoration of good Arab standing, renewal of an American dialogue, a boost for President Assad -- from the crisis already. The Begin government, under attack at home for bringing on and then misplaying the crisis, has been unable to draw the nation together and needs an escape hatch. Can Mr. Habib, with the Saudis helping in Syria, open one?

The Syrians, meanwhile, have jointed tentative talks aimed at eventual Lebanese "national reconciliation" -- getting warring Christians and Moslems to restore civil ties. In particular, Syria is talking with Christian Phalangists, whom Israel has sought to enlist as security partners. This is critical. National reconciliation is a long shot. To have the faintest chance, Syria must encourage the Christians to try it, and the Israeli-Christian connection must be loosened.It isn't clear to us whether Mr. Habib is poising to move into the Lebanese realm, or whether he should. Perhaps it is enough for the moment that the idea of reconciliation is stirring again in Arab minds.

Any reconciliation effort leads to the Palestinians, unwilling and unwanted residents of Lebanon who unwilling and unwanted residents of Lebanon who tear the country up. No reconciliation is possible without taking them into account. At the same time, Israel cannot and should not countenance any Lebanese scheme that lets Moslems and Christians co-exist but leaves Palestinians free to continue attacking Israel.

The evident answer is to divert Palestinian passions into political channels. Just as the Israeli-Syrian crisis fades into the Lebanese issue, the Lebanese issue fades into the Arab-Israeli conflict. It's a diplomatic Tinker to Evers to Chance. Crisis diplomacy and the Arab talks on Lebanon are incomplete without further contributions from the Israelis, after their elections next month, and from the United States as well. The Middle East, always a nervous place, is getting interesting again.