It is difficult to assess just how much Israel's invasion and three-year occupation hastened the disintegration of Lebanon. Israel rolled across the border June 6, 1982, to crush the Palestinian infrastructure established in the south, to force a Syrian withdrawal from the central and eastern sectors, and to install a pro-Israeli leader.
Thousands of Lebanese and Palestinian civilians were killed during Israel's invasion. Thousands more were wounded, and scores of thousands lost their homes. Millions of dollars worth of damage was done to the Lebanese infrastructure.
The population of west Beirut was forced to endure a nearly three month-long siege while the Israelis squeezed the Palestine Liberation Organization's guerrilla forces out of the mostly Muslim section of town in the summer and fall of 1982.
During the years that Israel occupied the lower third of Lebanon, the country was virtually cut in two, with the movement of goods and people between north and south reduced to a fitful trickle.
Eventually, many Lebanese came to blame Israel for most of the troubled nation's disasters. The desire to end Israel's occupation of the south was the closest thing to a common goal among the bitterly divided factions last winter and in the early spring of this year.
Guerrilla attacks by Shiite Muslims in the south on Israeli troops were hailed as acts of national heroism by most Lebanese. Israel's occupation served to involve the Lebanese in the Arab-Israeli conflict in a way no previous Middle East war had done.
Many analysts believe that the most lasting change spurred on by the Israeli presence may have been the awakening of the long-neglected Shiite community.
``The Israelis let the Shiite genie out of the bottle in Lebanon,'' says Jonathan Randal, veteran Middle East correspondent and author. ``They at least accelerated a process that had begun to take place.''
Surely, much damage had been done long before the Israeli invasion. The Lebanese civil war -- pitting Maronite Christians against Palestinians and their leftist Muslim allies -- began in 1975. Thousands of Lebanese were killed before Syrian forces entered Lebanon in April 1976 to put an end to the fighting.
But the countless militia battles waged in the years since then and after Israel's invasion paled, somehow, in comparison to the spectacle of the most sophisticated army in the Middle East throwing its forces against the Palestinian guerrillas and a large civilian population.
The invasion, says Samuel Lewis, until recently the US ambassador to Israel, was ``not just a misadventure, but a tragedy, a tragedy for Israel and for Lebanon.''
Despite the fact that the invasion dramatically altered the balance of power by driving out the Palestinians and paving the way for the rise of the Shiites, no single force has yet been able to subjugate the rest of Lebanon's many armed factions.
``The Palestinians were the dominant power among the Muslims in 1982. We broke their back and that changed everything overnight,'' explained one Israeli official involved in shaping Israeli policy in Lebanon.
With the completion of the Israeli withdrawal, expected today, it appears certain that Lebanon's bloodshed will not cease. Israel's future relations with the Lebanese depend in large part on the outcome of the power struggle now being waged.
Last month Shiite Amal militiamen, in a bid to consolidate power, attacked Palestinians in Beirut refugee camps. Amal leader Nabih Berri has said he will not permit the Palestinians to reestablish a foothold in the south. Syria, Lebanon's chief power broker, backs the Shiite effort to prevent the resurgence of Palestinian fighters who support PLO chairman Yasser Arafat.
In the last days of May, figthing between Shiites and Palestinians in the Beirut camps got so bad that Lebanese President Amin Gemayel appealed to the Syrians to intervene more directly to end the fighting.
Syria maintains some 30,000 troops in the central and eastern sectors of Lebanon and has close ties to Amal and the Progressive Socialist Party of the Druze religious sect. Syria also has supported Mr. Gemayel, a Maronite Christian, in the face of a rebellion within his own Lebanese Forces militia that sought to distance the Christians from Syrian control.
It is only a matter of time, according to Western diplomats in the region, before the Syrians move to cut back the increasingly powerful Amal. It is not inconceivable that some sort of rapprochement will be worked out between the Syrians and the pro-Arafat wing of the PLO. One of Israel's fears is that the Syrians will eventually allow limited guerrilla action against Israel's northern settlements again from Syrian-held territory in Lebanon.
As the Syrian master plan unfolds in a sequence of shifting alliances and battles in Beirut and other Lebanese cities, the Lebanese manage to endure. Veteran Lebanon-watchers have observed the seemingly endless capacity of Lebanese to rationalize the most horrific events in their increasingly anarchic society.
``They don't even have defense mechanisms,'' says Neff Walker, a psychology instructor at the American University in Beirut, who has conducted studies of the Lebanese ability to cope with stress. ``What we have found is that many of the people we talk to really do regard their lives as normal.''
Thousands of Lebanese who could not regard daily outbreaks of street fighting as normal fled long ago. Many have settled in Cyprus and the US.
Those who remain adapt themselves to the Islamization of west Beirut, once a model of intercommunal tolerance, or retreat to the various de facto cantons now being carved from Lebanese territory.
One Maronite Christian woman who has lived in west Beirut all her life says she prefers staying in west Beirut to joining her fellow Christians in east Beirut. She is opposed, she says, to Lebanon's cantonization.
The notion of cantonization, Lebanese style, is a far cry from the Swiss political model. In Lebanon, Druze warlord Walid Jumblatt has used the fighting prowess of his small but fierce minority to secure Druzistan in the Shouf mountains east and south of Beirut.
The beleaguered Maronites, for their part, hold onto east Beirut, Juniyeh, and the Lebanon Mountains north of the capital. Most Christians from the areas near Sidon have been driven south to the proposed Israeli security zone along the border or have fled to the north.
``There already is a Druze canton and a Christian canton,'' said the Israeli official. ``The problem is that one cannot establish a Shiite or a Sunnite canton under any circumstances. Their pockets are separated by the territories of the other factions.''
Syria has repeatedly stated its opposition to any formal cantonization of Lebanon, and it is equally opposed to the declared intention of such fundamentalist groups as Islamic Jihad (``holy war'') to create an Islamic state.
Most probably, analysts interviewed say, the Syrians will continue to hold together a weak Lebanese government and Lebanon, on paper, will continue to function as a single state.
``But it will exist only because it cannot be dismantled,'' says one political analyst. MAP: Who controls Lebanon? Christians and Druze control defined areas where most of their populations are concentrated. Shiites and Sunnis are dispersed throughout the nation. But Shiites are establishing dominance in west Beirut and south Lebanon. Christian militias Druze militia (Druzistan) Syrian military control Shiite militias Israeli Army and proxies Source: Economist, May 1985