From the cool comfort of the luxury summer villas that dot this Christian town high on the slopes of Mount Lebanon, the national capital of Beirut is but a whitish blur baking down below in the heat haze of the Mediterranean plain.

It is no doubt the Olympian quality of these pine-dotted heights, and the ill-defined image they afford of the shattered port below, that reduce the "Lebanese problem" to a political abstraction in the conversations of members of the nation's once-proud establishment as they gather for weekend luncheons in the hills, reenacting an age-old ritual of their class.

At one such recent gathering, the only unseemly reminder of the troubled existence of this land that used to advertise itself as the "Switzerland of the Middle East" was the sudden hollow boom that resounded over the hills as the host, a publisher and diplomat, mixed preluncheon cocktails for his guests -- a member of parliament, a couple of political backers, relatives and a journalist.

The host's hand hesitated but a fraction of a second as he poured a drink -- a reflex of those well-acquainted with how rapidly Lebanon's surface calm can deteriorate into the violence of war. That was just enough time for the host to determine that the dull concussions were but the result of the daily Israeli Air Force reconnaissance jets breaking the sound barrier.

The conversation only fleetingly touched on the general breakdown of Lebanese society after more than six years of first civil war, then Israeli invasions and battles among the heavily armed militias of rival political factions, Christian warlords, Islamic sects, Palestinian guerrillas, Arab goverenment proxies, street gangs and occupying Syrian Army troops of the Arab League's "peacekeeping" forces.

But the subject that elicited the most passion from the notables at the luncheon table was the seemingly arcane issue of who were the probable candidates for the country's 1982 presidential elections.

Never mind that Lebanon, divided into de facto Christian and Moslem enclaves, parceled out among more than 40 different militias, and occupied by 30,000 Syrian troops, is a nation in name alone.

The authority of President Elias Sarkis extends only a few miles from his palace above the capital. His five-year term is up next September and he has made it clear that he has no intention of seeking a constitutional amendment to extend his term, as some would have him do.

Politicians are debating who might be prevailed upon to take the task -- and be accepted by the Syrians, who have a quiet veto power.

Under Lebanon's constitution, which was designed to keep peace among the myriad sects by parceling out state posts on the basis of religion, the president must be a Maronite Christian. The prime minister must be a Sunni Moslem and the speaker of parliament a Shiite Moslem.

The Maronites today, however, are a particularly beleaguered lot, accused by the majority Moslems and the Palestinians allied with them, of unleashing the 1975-76 civil war that unraveled the social fabric of the nation of 3 million.

Even though Maronites are treated as political pariahs, there is a surfeit of potential candidates --old politicians, bankers and potential dark horses are reported to be seeking the sort of political deals that would allow them to get their campaigns rolling.

Writing in the influential Beirut daily An Nahar, journalist Michel Shweiri made a distinction between "candidates of luncheons and get-togethers" and "serious candidates," whom he numbered as eight in all.

Despite the barb in the journalist's distinction, the luncheon crowd in Beit Meri agreed on the seriousness of four of the eight he named.

Two are crusty ex-presidents, leaders of rival Maronite clans, and sometime warlords: Camille Chamoun, 81, who as president in 1958 called in the U.S. Marines to end Lebanon's first civil war, and Suleiman Franjieh, 71, who preceded Sarkis in the presidency.

Franjieh is a sworn enemy of the Gemayel clan, whose Phalange party and Israeli-equipped militia is the dominant power in the Christian enclave that extends north along the coast from the "green line" that separates Christian East Beirut from Moslem West Beirut.

Both former presidents are being advanced as candidates because they might prove acceptable to the Syrians--who oppose the Gemayels for their previous, though recently renounced, ties to Israel.

Should the Gemayels manage to derail the candidacies of the ex-presidents, two independent possibilities are Michel Khoury, son of Lebanon's first president, and millionaire dark horse Manuel Younes, a former emigrant to Mexico.

For many Lebanese, the early jockeying for position bodes ill. In the best of times, Lebanese elections sow tension and violence -- and these are the worst of times, to say the least.

Since June, when an Arab League peace committee worked out a cease-fire in the often indiscriminate war of artillery in Beirut between the Syrians and Bashir Gemayel's Christian "Lebanese forces" in East Beirut, a shaky truce has reigned.

Even so, more than 100 persons--including French ambassador Louis Delamare -- have been killed in the past month in clashes among the militias who remain the real powers in the land, or in those small turfs, or often city blocks, that they control. The Arab League "follow-up" peace committee includes foreign ministers of Saudi Arabia, Kuwait and Syria, as well as the league secretary general, and is chaired by President Sarkis. It has only just managed to preserve a "detente" between the rival forces.

The committee has failed to make any real progress toward national reconciliation, a general disengagement of rival armed forces or a curb on the arms they receive.

"In the current climate of tension and suspicion," notes one Christian politician, "to begin talking presidential politics is going to make reconciliation and peace more, not less, difficult."

For all the talk of presidential politics in places like Beit Meri, Lebanon remains a country where politics are determined by the gun and the presidential elections, it is feared, will only prove the rule.