A Druze leader with his finger on the trigger of a civil war

He favors leather jackets and well-worn jeans, although the belt buckle and shoes are French designer makes. What remains of his long wispy hair is unkempt, and his words - in French, English, or Arabic - are spoken with deep passion, accompanied by gesticulating hands. He looks and acts more like the poet and writer he once wanted to be.

But Walid Jumblatt has instead vented his fury on politics, a role forced on him after the assassination of his father in 1977. Mr. Jumblatt inherited the leadership of the Druze Muslim community and Lebanon's leftists. And he has now emerged as the main force behind the reform movement in Lebanon, threatening the government with a new civil war if it does not give the Muslim majority greater representation in the government dominated by minority Christians.

It was the militia of his Progressive Socialist Party that kidnapped three Cabinet ministers earlier this month. It was simultaneous shelling from his Druze guns in the hills of the Shouf mountains southeast of Beirut that closed Lebanon's international airport for six days, holding it hostage to prove Druze clout and commitment to change.

And it was Jumblatt who acted as the main ringleader behind the ''National Salvation Front,'' a recent alliance including seven parties, a former prime minister, and former president that opposes the government of President Amin Gemayel.

He has backed up his words with actions, leading to a dangerous confrontation that threatens the very survival of Lebanon as a nation.

Ironically, for most of the past six years Jumblatt has been considered a weak figure. He has been said to be dependent on advice from his strong-willed mother, prone to indulge in some of the activities forbidden by his strict Islamic faith. Some diplomats have judged him a puppet of various Middle East influences; at the moment it is Syria, which is backing both him and the National Salvation Front.

He certainly did not initially appear to take after his father, Kamal Jumblatt - a charismatic leader named to several Cabinet posts and an author of major political treatises. His father was known as ''al Mu'allem'' - teacher and wise man. The younger Jumblatt inherited that title, too, but until recently he offered only minimal leadership.

Although he clearly could not follow his current course without Syria, Jumblatt increasingly appears to be his own man, developing the platform laid down in the 1950s by his father to modernize and secularize Lebanon's confessional political system.

He now has what a Beirut newspaper described as ''an undeniable flair'' for politics. And the loyalty of his followers was evident after a foiled assassination attempt by car bomb last December. Hundreds of supporters flocked to the hospital grounds after the attempt and chanted in Arabic, ''With blood and spirit, we will sacrifice for you, oh Walid.''

The angry young man, like the Lebanese President, is from the second generation of Lebanese politicians. Mr. Gemayel's father founded the Christian Phalangist Party. The two fathers were key figures in the freeing of Lebanon from the French in 1943. Their sons may be at the heart of its dismemberment.

It is the Druze-Christian conflict in the Shouf, where sporadic fighting has killed more than 300 in the past 11 months, that triggered the current crisis and the Jumblatt militancy.

Jumblatt explained last week: ''The Phalangist Party aims at destroying the Druze community, after which it will strike at the dense Shiite Muslim population centers in Beirut and then expel the remaining Palestinian civilians from Lebanon.

''We shall not allow this scheme to take place. We shall fight to the bitter end. We have nothing more to lose, and let everyone face up to his responsibility.''

As the only alternative, he said, ''We have to achieve a national compromise in Lebanon. Either we achieve it or we'll go into this endless and bloody civil war.''

His recent actions have sprung from his greatest fear: ''I think one day the Druze will be like the Armenians, a people without a country,'' he said in May.

The Druzes, who are the fourth largest of Lebanon's 17 sects, are estimated to number 300,000 out of a Lebanese population of 3 million. A ''closed'' community, the Druzes have a secret doctrine and do not accept converts. They originally came to Lebanon from Egypt centuries ago to avoid religious persecution and settled in the then-isolated Shouf mountains, just as the Maronite Christians did on leaving Syria for the same reason.

However, the Druzes have traditionally played a role disproportionate to their numbers, as reflected in the fact Jumblatt has also become the most active Muslim opposition leader in Lebanon.

He is currently using the dispute in the mountains only as a symbol of the need for national change, and the possible cost without it. Even Muslim moderates and far more experienced politicians, including former Sunni Muslim prime ministers, have backed his appeals for reform.

And the Shiites, Lebanon's largest religious community, have joined him. ''Amal'' leader Nabih Berri is serving as his chief go-between with the government, since Jumblatt has refused to return to Beirut for the past five months, in part due to personal security concerns. He operates mainly out of Jordan and Syria and travels to Syrian-controlled areas in the north and east of Lebanon.

Jumblatt's concern for other Muslim communities is in part the result of the influence of the late Egyptian President Gamal Abdel Nasser. He grew up in the golden age of Arab nationalism and as a very young man met with the Egyptian leader three times.

He also was a strong supporter of the Palestine Liberation Organization and led 13 Lebanese militias from all Muslim sects in the now-disbanded ''National Movement'' to fight alongside PLO guerrillas until their evacuation last summer.

Although, like President Nasser, Jumblatt is a socialist, he is not considered a Marxist. Indeed the Druzes traditionally have operated as feudal clans.

Jumblatt is strongly critical of both superpowers. ''We feel that the big powers - the United States and the Soviet Union - do not want the unity of the Arab nation or the Islamic bloc,'' he said in May.

''We must note that the USSR has been absent (in the Middle East) since the 1973 Arab-Israeli war, while the Americans create wars in order to get a settlement,'' he said. The latter was a reference to the widely held view among Muslim leftists that the US gave Israel a green light to invade Lebanon.

He has left doors open to both superpowers, visiting both countries in the past two years for high-level talks. And when his involvement was sought in a government crisis council at the beginning of the Israeli invasion last summer, he accepted protection in a US Embassy car for the drive from his home in the Shouf, behind Israeli lines.

Diplomats and Muslim sympathizers tend to feel Jumblatt has also left the door open to the Gemayel administration. As he said last week, he was ''forced'' to take action against the airport and the Lebanese Army ''when I found myself cornered (politically) and all attempts to reach agreement with the administration failed.''

Jumblatt has been calling for reforms on behalf of the Muslims since coming to power, and he has been predicting major new civil strife since the turn of the year.

With every indication of government intransigence, the Druze leader has increased his demands. On Aug. 11, he issued a more militant list of conditions for an end to the fighting, including the resignation of the prime minister and his Cabinet.