Special U.S. envoy Philip C. Habib's mission to ease the Middle East missile crisis may not succeed, but already many Lebanese have concluded they have lost out once again in any case.

President Elias Sarkis, a man not given to expressing his feelings in public, grasped the national mood at a Cabinet meeting this week when he said, "The only losers are Lebanon and the Lebanese."

His pessimism reflected the conviction that the superpowers, especially the United States, were interested only in solving the Syrian-Israeli missile dispute.

After six years of warfare that has transformed Lebanon into the Middle East's proxy battlefront, superpower involvement has become a national obsession here, where it is seen as the only way to end Lebanon's seemingly endless penchant for violence and Byzantine politics.

Since the current fighting began April 2, more than 500 Lebanese -- mostly civilians -- have been killed, and the outside world is seen as only too willing to shelve the Lebanon problem if allowed to.

Among the Lebanese, the biggest losers generally are seen to be the right-wing Christian militias. They still hope -- without much conviction these days -- that Israel will provoke just enough of a war to force the superpowers to deal with purely Lebanese matters on their terms.

But the Israelis did not intervene when we expected," a top Christian leader said, referring to the initial fighting in early April, "and they did intervene when we no longer expected" in shooting down two Syrian helicopters April 28.

Openly contemptuous of their erstwhile Israeli allies, whom they accuse of having lost their pioneering spirit, the Christian militia leaders have seized on what they perceive as U.S. government support to alleviate an otherwise depressing situation.

So far the biggest winner, in their opinion, is Syrian President Hafez Assad. With Soviet support he has broken out of his isolation within the Arab world, become the first Arab leader to have faced down the Israelis and strengthened his hand in Lebanon.

The Christian militias dreamed of forcing the 22,000 Syrians who make up the Arab League truce force to leave Lebanon or at least agree in principle to a departure timetable.

But the Arab League foreign ministers opened a special meeting in Tunis today that tacitly is expected to give an official blessing to an open-ended Syrian presence and to resume funding of the force, which was suspended earlier this year.

Now the Christian leadership is faced with a more demanding Syria and a population whose educational, economic and social life has been disrupted for almost two months. For the time being no one in the Christian community has challenged the leadership.

Other apparent losers are the Palestinian guerrillas, weakened now that the uneasy balance between their theoretical allies, the Syrians, and their nominal adversaries, the Christian militias, has been upset.

Unlike earlier confrontations here, this time the Palestinians stayed out of the fighting. But an increased Syrian role here can only mean less freedom to maneuver. And that is the only good card held these days by Yasser Arafat of the Palestine Liberation Organization.

Moreover, with six weeks to go before Israel's elections, the Palestinians are convinced Israeli warplanes will resume massive raids once the Habib mission ends either in failure or triumph.

In between these two extremes are such powers as Saudi Arabia and other conservative Arab states. Useful to the United States because of Washington's own lack of clout in Damascus, the Saudis reportedly did what they do best in Middle East crises: they paid up.

Whether they paid Syria $1 billion, as some publications have reported, is unclear. But the Saudis presumably backed Syria with more than diplomatic support and may have paid their arrears for the truce force.

Saudi Arabia had little interest in seeing the Soviets increase their influence in Syria, force conservative Arab states to follow suit and thus become estranged from the West.

For Lebanon the prospects are ever more depressing. On both side of this divided capital sandbags surround buildings, schools are closed and ever more sophisticated and deadly weapons are being used.