A strange and wonderful thing was supposed to happen in Beirut Sunday. Ordinary people were going to march for peace after nine years of shellfire, sniping, kidnappings, and murder.
But new gun salvos along the ''green line'' between Beirut's Christian and Muslim halves intervened on the eve of the planned march, compelling its postponement.
Lebanon's war-weary, forcibly silent majority may yet, in the days ahead, hold its march. The 29-year-old kindergarten teacher who hatched the idea may yet turn an impressive groundswell of support for it in recent days into a public demonstration. She and many of her compatriots want to show that, whatever religion may be listed on their identification cards, they are sick and tired of violence.
There was at least one hint of progress Sunday toward unblocking moves to assemble a new ''national unity'' government of Lebanon's rival warlords. One of two holdout political leaders earmarked for a Cabinet post - Druze chief Walid Jumblatt - suggested he had decided to join the Cabinet.
Yet the other current holdout - Nabih Berri, who leads the country's disadvantaged Shiite Muslim majority - was still refusing to join at time of writing.
As consultations continued on ways around the logjam, the postponement of the Beirut peace march seemed a reminder that the rival politicians and their well-armed militias remain the key local determinant of war and peace.
The key outside determinant is neighboring Syria, which is more than ever intent on showing that it can impose a measure of stability on Lebanon, where the Americans and Israelis have failed.
Mr. Berri was originally handed the Ministry of Justice in the proposed government lineup. He has demanded instead that two new government bodies be set up under Shiite leadership. One would deal with the affairs of Israeli-occupied southern Lebanon, in which Shiites are the majority. The other would direct reconstruction efforts in war-damaged areas of Lebanon, notably in the tattered, impoverished, largely Shiite suburbs on the southern fringe of the Lebanese capital.
But the Berri demand is at least as important for its symbolism as for its substance.
The substance may well be handled - presumably with more than a bit of Syrian political muscle - through the kind of acrobatic verbal compromise that has always marked Mideast political accords. This would seem the minimum for which Berri, with more militant Shiite rivals snapping at his heels, can settle.
But Berri's demands imply, in the long run, a wholesale shift in the power-sharing arrangement on which Lebanon has run for decades. That setup favored the country's Maronite Christian community, placed Sunni Muslim leaders second in the pecking order, and handed the Shiites considerably less say in affairs of state.
A Syrian-mediated bid to put such a shift down on paper in a way Maronite warlords could accept failed at a ''reconciliation conference'' in Lausanne, Switzerland, in March. The Lausanne failure came despite the fact that, with Syrian help, Shiite and Druze militia forces had just battered the Army of Lebanon's Maronite President Amin Gemayel, and thus had theoretically set the stage for key Maronite concessions.
The attempt at formation of a new national government in Lebanon - also with strong Syrian involvement - in effect represents Damascus's bid to achieve in Beirut what proved impossible around a stately conference table in Lausanne.
In a rare acknowledgment of less-than-convincing Syrian success, Damascus radio said on the heels of the Lausanne parley that its results ''may not have fulfilled completely'' expectations.
But the radio commentary served notice that Syria was not about to give up on its bid to demonstrate that ''Lebanon is strengthened with Syria, and weakened with the United States and Israel.''
''The steps which have been achieved are only the beginning, not the end of the course,'' it said. ''Those who expected miraculous solutions from Lausanne are not living in the world of reality. And those who lost hope after Lausanne are also remote from reality. . . .''
The Syrians' advantages in their quest are various. There are at least 40,000 Syrian soldiers in Lebanon, a force that entered in 1976 in an earlier bid to impose a compromise pax Syriana on Lebanon's rival communities after some 18 months of civil war. Militarily, Syria commands the strongest single force in Lebanon.
By careful calibration of backing for non-Christian militiamen, the Syrians have achieved on the ground something approximating stalemate among the Lebanese rivals. None of the militias can definitively defeat its foes at present - especially given Syria's commitment to intervene to prevent a Lebanon of ''victor and vanquished'' that would threaten to trim its own sway there.
But the message of Lausanne was that mere muscle is no guarantee of Syrian success, or at least of neat and quick Syrian success, in mediating the creation of a workable new power-sharing arrangement in Lebanon.
Militarily, Syria seems reluctant at least for now to interpose itself in Lebanon's rivalries, despite official suggestions this could change if efforts at a negotiated settlement fail. Bazookas, after all, aren't always effective against peashooters. This the Syrians learned in intermittent face-offs with Maronite militia gunmen in Beirut in 1978.
Politically, various of Lebanon's rival warlords - not only Shiite but also Maronite - have seemed to sense that they can safely hold out, at least for now, for bettering their position in any compromise.