Washington — After nearly a year of high-pitched Middle East diplomacy, the Reagan administration has decided, in effect, to tone down its efforts and let the Lebanese, Saudis, and others carry on for a while.
The name of the American game is to bolster Lebanon, keep everyone talking, and then move toward more high-level US diplomacy - including, possibly, a United States-Syrian foreign ministers meeting here or another George Shultz visit to the Middle East - only when the time seems right. The hope of some observers that Syria might quickly withdraw from Lebanon has collapsed.
State Department officials say that what is called for is patience. But they recognize that the patience of Israel is limited and that recent attacks on Israelis stationed in Lebanon could provoke a major response against Syria. The officials say that a hopeful sign is an intense Syrian interest in a continuing dialogue with the United States.
The State Department is convinced that with time, the Syrians will recognize that it is in their interest to agree to a withdrawal that would bring a pullout of Israeli forces now situated within 15 to 20 miles of the Syrian capital, Damascus.
''I think optimism . . . is warranted,'' said Morris Draper, special US envoy for Lebanon negotiations in an ABC News interview Sunday. ''But I think we have to be patient for results. It's a very sticky period right now.''
Mr. Draper listed the factors working against Syria's holdout position:
* Israeli forces in a position to drive into northern Syria should a major confrontation break out.
* Widespread Arab support for Lebanon's right to make the kind of decisions it did when it reached an agreement with Israel.
* A strong consensus within Lebanon itself and in its parliament in favor of the Lebanon-Israel agreement and the withdrawal of both Syrian and Israeli troops.
The counterargument is made by some that Syria may look at Lebanon as an opportunity to drain Israel's resources, both economic and human. The continuing Israeli occupation, and Israeli casualties, have generated intense debate within Israel. A member of Syria's minority Islamic Alawite sect, President Hafez al-Assad has only a narrow base of power. Playing the role of a strong, ultranationalist leader resisting the Israeli threat may make for good domestic politics as far as Assad is concerned. And finally, his Soviet backers may want him to stay put in Lebanon.
Draper's answer: ''The chances of a confrontation between Syria and Israel remain very high. I don't think the Soviet Union could see any advantage in another confrontation occurring when it might well be a repeat of what happened last summer with all that that implied for the quality of Soviet support and Soviet weapons.''
Draper was speaking of last summer's attacks by the Israeli Air Force in which the Israelis blasted Soviet-supplied radar and missiles and shot down at least 85 Soviet-made fighter planes flown by Syrian pilots. The Israelis apparently lost only one plane to the Syrians. Although the Soviets have now provided the Syrians with SA-5 missiles and Soviet personnel to help man them, State Department analysts predict that a new flare-up would lead to another lopsided Israeli victory.
Washington's analysts are divided as to the chances of another such Syrian-Israeli flare-up's occurring. But State Department officials say that despite their heavy investment in Syria, the Soviets' leverage over President Assad is limited. Assad has demonstrated in the past that he is his own man. He has traditionally been able to play what is described as a spoiler role.
If Soviet leverage over Assad is limited, this is, of course, even more the case when it comes to the Americans. US diplomats are now hoping that direct appeals to the Syrians from Lebanon, and behind-the-scenes appeals by Saudi Arabia, which helps to bankroll Syria, will eventually have some impact.
State Department officials had considered giving President Assad a ''high-level jolt'' with a visit to Damascus by Secretary of State George Shultz's deputy, Kenneth W. Dam, or by Undersecretary of State Lawrence S. Eagleburger. But the idea was dropped because their chances of accomplishing much seemed minimal.
Critics argue that US policy is simply drifting, merely reacting to events rather than following a farseeing plan.
In addition to their effort to obtain the withdrawal of the Syrians and Israelis from Lebanon, officials have vowed to press ahead with President Reagan's Sept. 1 plan for a resolution of the Palestinian question. But in private conversation, State Department officials express grave disappointment in the Palestine Liberation Organization and its inability to react decisively to President Reagan's proposal that a Palestinian entity on the West Bank of the Jordan River be linked with the Kingdom of Jordan. Officials are concerned about reports that some hundreds of PLO fighters have been ''infiltrating'' back into Lebanon.