Israel will redeploy its troops in Lebanon - despite President Reagan's expected plea. But the timing could be modified. Syria has won the first round.
The appointment of Richard C. McFarlane is widely seen by Arabs as a concession to the Syrians. President Hafez Assad has been holding up the peace process by refusing to talk to the United States, specifically former special envoy Philip Habib, on withdrawal of foreign forces from Lebanon.
The Syrian government newspaper, Tishrin, over the weekend called Mr. Habib ''an enemy of the Arabs'' because of his ''false and misleading promises.'' But, in fact, the opposition to Mr. Habib was more a symbol of Syrian opposition to the US-designed accord between Israel and Lebanon, which allows a residual Israeli military presence on Arab soil.
However, Tishrin in effect welcomed Habib's replacement. A long editorial predicted that Mr. McFarlane would be more effective than his predecessor.
The general reaction among many Arabs was ''at last.'' Officials and envoys had predicted Mr. Habib would have to go - as a token gesture - to revive the US-Syrian dialogue.
The move was also seen as providing a glimmer of hope that Washington had become more realistic about the obstacles blocking progress on its plans to resolve both the Lebanese crisis and the broader Arab-Israeli conflict.
Mr. McFarlane's credentials may impress the Syrians, since the former State Deparment official now comes directly from the White House. And his experience as a Marine colonel may appeal to Mr. Assad, a former minister of defense and air force officer.
Syria may hope the appointment signals Washington's awareness of Syria's primary goal in blocking peace: security concerns. Syria is fearful of the long-term implications of allowing Israeli soldiers to operate in Lebanon.
However, the initial Syrian welcome could be somewhat shaded by the enthusiastic Israeli reaction to the appointment. Prime Minister Menachem Begin's spokesman said the Israeli leader was ''very impressed by him'' during meetings in Jerusalem in 1981 after Israel bombed Iraq's nuclear reactor. It will also be difficult to replace Mr. Habib, whose Levantine ancestry and long experience in labor and diplomatic negotiating gave him a special sensitivity to the ''atmospherics'' of Middle East diplomacy.
But a change of face was necessary as a symbol of the fresh impetus needed to avoid total collapse of US peace efforts. It will open the way for talks divorced from earlier negotiations with the Israelis - or so it will appear, which is what the Syrians are after.
The US must be prepared to go much further now, if it hopes to really crack the deadlock, in the opinion of diplomats and Middle East analysts.
So far, Washington - and the Israelis - appears to think that in due time the Syrians will feel the political and financial costs of keeping 40,000 troops in Lebanon are too high. The Syrians, perhaps spurred by constant Arab pressure and a possible war of attrition with Israel, will find it in their best interest to withdraw.
That approach has led to despair among those Lebanese and diplomats who had hoped US clout would finally end the cumulative eight-year crisis in Lebanon. There are strong indications that Syria is not prepared to succumb to that strategy.
This was most evident over the weekend when Druze leader Walid Jumblatt announced a new ''National Salvation Front,'' a grouping of seven leftist political parties to be led by Mr. Jumblatt, former Lebanese President Suleiman Franjieh, and former Prime Minister Rashid Karami, to oppose the government of Lebanese President Amin Gemayel. In effect, it is an opposition government, complete with a Cabinet to run local affairs in Syrian-occupied territory.
Although it reflects the deep division among Lebanese, the Salvation Front could not have been formed without the support, aid - and perhaps even prompting - of the Syrians. Mr. Jumblatt traveled to meetings with his co-leaders in Syrian helicopters.
In Paris, on his way home from Washington, Mr. Gemayel denounced the pro-Syrian opposition group saying, ''Ninety-nine point nine percent of the Lebanese people is with the Lebanese government. . . . The figure is even higher in the (Israeli and Syrian) occupied zones.'' He added, ''Unfortunately there are elements exploited to cover up the occupation of Lebanon. It's not an opposition. It's what I call a helicopter-borne opposition . . . in Syrian Army helicopters.''
The creation of the Salvation Front was interpreted in part as the Syrian answer both to Israel's plans to withdraw partially and consolidate its hold in southern Lebanon, and to Mr. Gemayel's talks in Washington.
The Syrian message was: We can both hold out and stir up new troubles for Lebanon until Washington sees fit to meet our terms, with Lebanese and Israeli concurrence.
Thus Western and Arab envoys say the US policy of thinking time is on the side of peace is shortsighted. Mr. Assad has repeatedly made clear that he is playing for bigger stakes.
On the Lebanese crisis, he is looking, at minimum, for concessions that will allow a strong Syrian ''influence'' in the Levant - an influence stronger than Israel's residual military presence.
And on a broader peace, he is aiming to be the main power broker on terms that will lead to a Palestinian homeland and return of the strategic Golan Heights, captured by Israel from Syria during the 1967 war and annexed by Israel in 1981.
Although the appointment of Mr. McFarlane was accompanied by talk of new approaches, it is widely felt by diplomats in the region that the unspecified and almost secretive measures do not include major shifts sufficient to satisfy the stubborn Syrians. Major policy changes may also be difficult for the Reagan administration as the election approaches, since Mideast policy could become a major campaign issue.
The growing sense of despair among Arabs, particularly Lebanese, was reflected in Beirut's moderate Monday Morning magazine this week. It editorialized: ''The time has come for America to translate its words into deeds. It is no longer enough for Washington to declare its support.'' And it blamed the White House for a string of Middle East troubles, ranging from the impasse in peace efforts to the Palestine Liberation Organization mutiny, mainly because Washington had allowed too much time to pass.
Like the Syrians, even the moderate Lebanese have begun to express dissatisfaction with the US approach, feeling that the commitment is inadequate, that the will and interest are not backed by any muscle. Mr. McFarlane will have to do some fast diplomatic hustling to convince both US allies and those, like Syria, that it hopes to entice into the peace process that Washington is able to follow through on its initiatives.
Meanwhile, in Lebanon's Bekaa Valley fighting broke out again for the third straight day Monday between PLO guerrillas loyal to Yasser Arafat and those opposed to his leadership.
The recent fighting, among members of the Fatah guerrilla group, broke a three-week old ceasefire negotiated by PLO mediators. The battles raged as Mr. Arafat arrived in Taif, Saudi Arabia for talks with King Fahd on the mutiny within Fatah.