For the first time since June, Lebanon appears threatened with a military and political breakdown. Major battles in the Shouf mountains overlooking Beirut spilled over into the Lebanese capital Sunday night and Monday morning, hitting residential areas in the Christian sector.
This was the first significant battle since the Syrian-arranged security plan went into effect during the summer. The thunder of rocket fire led many to seek shelter in basements once again. Several cease-fire attempts failed until a truce was called early Monday.
The clashes between the Lebanese Army and Muslim factions coincided with an escalation in the war of words among Christian and Muslim warlords in Lebanon's ''national unity'' Cabinet.
The future of the six-month-old government of Prime Minister Rashid Karami seemed uncertain after two of the most powerful Muslim officials renewed their threats to resign over the weekend. Both issued the angriest denunciations of the government since the various factions were brought together in a new cabinet , also with Syrian backing.
Nabih Berri, leader of the Shiite Amal movement and a Cabinet minister, lashed out at President Amin Gemayel, calling him ''the king of postponement and procrastination.''
At a press conference he charged that Mr. Gemayel ''is opposed to the abolition of political sectarianism, that is, against giving the citizen his right to live as a citizen. At the same time, he is against achieving even justice among sects.''
Mr. Berri also said the President had no interest in freeing south Lebanon from two years of Israeli occupation, the most sensitive issue facing Lebanon. Maronite Christians, he said, ''want the foreign and internal occupation to stay. They want to use Israel as a backup for them.''
The Shiite leader, who left Sunday on a trip to Kuwait and Algeria, said he would decide on his return whether or not to remain in the Cabinet and ''confront procrastination.''
Druze leader Walid Jumblatt also threatened Sunday to resign. ''We agreed upon certain things at the reconciliation summit in Switzerland, and now we have formed committees to bury these proposals,'' he told Beirut's Monday Morning magazine. ''We think the President, and possibly the prime minister, are not serious about reforms. I will resign. I will not be one of the godfathers ... of a Cabinet that provides a cover for President Gemayel's plans.''
Christian officials responded by daring Berri and Mr. Jumblatt to ''resign their ministerial posts - if they have the freedom of decision and action.'' The statement was interpreted as suggesting the two leaders could not act without Syrian approval. Indeed, diplomats and Lebanese analysts feel only Syrian intervention will prevent further deterioration in the political and military situation.
Although tension has been mounting because of lack of progress on constitutional reforms, the Cabinet had finally agreed on small steps that might have paved the way to resolving the basic issues behind almost 10 years of civil war.
But the plan apparently encountered problems at a stormy Cabinet session Saturday. In a pattern all too familiar to Lebanese reconciliation efforts, government efforts to reestablish control over the Lebanese ports now run by various militias led to squabbling among the militia leaders who make up the government.
Other measures in the plan included:
* Reestablishing government control over the airport, Parliament Square, the telecommunications exchange, and other key positions.
* Stabilizing the Lebanese pound, which has fluctuated wildly recently due to speculation and political uncertainty.
* Combating smuggling and removing subsidies on fuel to boost state revenues.
More troublesome for the reconciliation effort is the fact that these steps are a long way from the major issue of evening the balance of power between majority Muslims and the minority Christians, who dominated the government.