Syria's mettle tested by Lebanese foes. Will concession on presidential choice appease Christian hard-liners?

Lebanon - just three days from a presidential election - again finds itself on a knife-edge, with nobody able to predict the outcome. Perhaps the one thing the deeply divided Lebanese had been able to agree on was that an understanding between the United States and Syria would provide the most likely deterrent to sliding further toward new levels of political crisis.

Signs of such an understanding were made public yesterday, when it was reported that United States envoy Richard Murphy and Syrian officials had reached agreement ``in principle'' on a compromise candidate for Lebanon's president.

But now political observers question whether even such an agreement will suffice to break Lebanon's political deadlock.

The compromise choice - Michel Daher - is expected to be as unacceptable to hard-line Lebanese Christian political and militia leaders as Syria's earlier choice. On Aug. 18, the Lebanese Forces Christian militia boycotted and blocked the election of former President Suleiman Franjieh. Mr. Daher, reportedly Syria's fallback choice, is a close associate of Mr. Franjieh and has advocated a strong Syrian role in Lebanon.

``We will boycott any election in which there is only one candidate, one who does not stand for national entente, but rather for national discord and a continuation of the conflict,'' Kerim Pakradouni, deputy commander of the Christian Lebanese Forces militia, said in a recent interview. The Lebanese Forces had indicated it would resist attempts by ``outside'' powers to influence the election.

Mr. Murphy, US assistant secretary of state for the Middle East, arrived in Beirut Sunday to consult with Christian leaders before parliament's scheduled vote for a president. The vote is due on the last possible day - Sept. 22. (President Amin Gemayel's term ends Sept. 23.) By press time yesterday, it was unclear whether the Christians had agreed to back Daher.

If Parliament fails to produce a new president, there will be a constitutional vacuum. Then, hard-line Christian leaders say, Mr. Gemayel would form a transitional government headed by a Christian prime minister to fill the gap. This would fly in the face of the covenant by which Lebanon has been governed since independence, under which a Muslim has filled the post of premier.

Syria and its Muslim allies have already denounced any such step as a ``partitionist scheme,'' reaffirming their support for current acting Prime Minsiter Selim al-Hoss.

With the two sides exchanging accusations and tensions rising, such a scenario could lead to violence.

This latest crisis was sparked by Syria's earlier support for Franjieh, whom the Christians rejected as too pro-Syrian. Since the election boycott, the Syrians have continued to encourage allies and proxies to take positions that, observers say, are aimed at pressuring the hard-line Christians.

Observers detected in this brinkmanship a Syrian insistence that the presidential election must be an occasion for change. So far, Damascus has refused to agree to election of a president who would perpetuate the status quo, in which Lebanon's Christians wield more political power than the country's Muslim population.

Signs are that Syria wants to use the election to break the deadlock that has paralyzed Lebanon since January 1986, when the current Christian militia commander, Samir Geagea, revolted against a Syrian-sponsored accord and ousted his predecessor who had signed it.

Damascus was attempting to make its approval of a consensus candidate conditional on acceptance of a reform package that would strengthen the Muslim role, and Syria's own influence, in Lebanon.

Yet, despite the ominous signs, there was surprising optimism on both sides of Beirut that the US would be able to sort it out with Syria.

``We're already 90 percent of the way toward holding presidential elections before the 23rd, and covering the last stretch, despite the difficulties, is being worked on,'' prominent parliamentary sources told the Syrian-inclined paper, Al-Safir.

``We're still betting on a president emerging in the last quarter of an hour,'' Mr. Pakradouni said in east Beirut. ``I'm optimistic that the Lebanese and international wills will produce a consensus president before the 23rd. ... Murphy's arrival in Damascus is itself 50 percent of the solution, and the other 50 percent is up to the negotiations.''

Underlying the hopes, perhaps, is the unspoken belief that it is not in Syria's basic interest to see Lebanon plunged deeper into chaos. If no agreement is reached and the scenario of confrontation and partition proceeds, it is hard to see how that would serve Syria's ends. Violence has in the past has only unified the Christian camp and stiffened its defiance. And Syria has, so far, shrunk from sending its troops into east Beirut to crush the Christian militia.

Hence the special role allotted to the US. The Americans, Syria says are the only party capable of exerting sufficient pressure on the Christians to neutralize the Christian militia or to encourage the Lebanese Army commander, Gen. Michel Aoun, to do the job by military means. So far, Damascus complains, Washington has failed to do either.

While the Syrians looked to the US to induce change in east Beirut, the hard-line Christians hoped Murphy could persuade Damascus to accept a compromise candidate without prior agreement on political reforms.

If Murphy fails to win Christian agreement, the Syrians face a choice: They could back down and accept a colorless president just to keep the peace; or they could press ahead with their attempt to impose their choice, thus deepening Lebanon's political crisis.

So far, Syria has seemed determined to try to tighten its grip on Lebanon. Its main fear appears to be that arch rival Iraq, now freed from the war with Iran, will use Lebanon as a springboard for anti-Syrian activities. Syria is wary of the deepening relationship between Iraq and the Christian militia, whose officials admit that Iraqi interest in Lebanon has been rekindled since the Gulf war cease-fire.