THE Reagan administration's cautious exploration of improved relations with Syria is useful. The practical advantages of full diplomatic relations with a nation usually outweigh the theoretical pluses of a diplomatic freeze. For better or worse, Syria is a key determinant of Middle East stability. What happens ultimately in Lebanon, with any peace arrangement between Arabs and Israelis, and what general progress is made in the area depend in large measure on Syria.
US-Syrian relations have been strained since last fall, when the Reagan administration recalled its ambassador to Damascus, William Eagleton, and ordered US oil companies to leave. That action was spurred by the clear involvement of some Syrian elements in the aborted effort last year to place a bomb aboard an Israeli airliner in London. The moves fell far short of the sharp break in diplomatic ties then urged by the Thatcher government. The failure to consult Syria in the US-brokered 1983 agreement by which Israeli troops were to withdraw from Lebanon gave the United States a vivid lesson in the importance of involving Syria and keeping a good working relationship with it.
The US ambassador to the United Nations, Vernon Walters, met this week with Syrian President Hafez Assad in sessions the US described as ``friendly, fruitful, and extensive.'' Ambassador Eagleton is now expected to resume his Damascus post before the end of the month. The Reagan administration's stated rationale for the warm-up in relations is Syria's noticeable recent moderation on global terrorism. Cited by the US as factors in this are the closing of the offices in Damascus of Abu Nidal, the Palestinian terrorist, and of his training camps in Syria, as well as the failure to track to Syria any terrorist plots against Americans in recent months. Also figuring in the mix are Syrian efforts to gain the release of US hostage Charles Glass from his Lebanese captors and its demotion or firing of the former Syrian Air Force intelligence chief implicated in the aborted airline bomb attempt.
Although the Reagan administration does not say it, a more important spur in firming up diplomatic ties with Syria just now is probably Washington's growing concern over recent headway made in the Middle East by the Soviet Union. In addition to its new presence in the Persian Gulf, Moscow has endorsed the concept of a Middle East peace conference. The Soviets have also established new diplomatic ties with several Gulf states and continue to try for some kind of working relationship with Israel. The US, long the only country in communication with all the players in the Middle East, has no desire to be outmaneuvered diplomatically.
Syria remains an ally of the Soviet Union, relying on Moscow for most of its weapons. But Damascus is no Soviet puppet. The Soviets probably have as much trouble as anyone else persuading President Assad to follow their bidding. Witness Moscow's irritation with Syria's continued backing of hard-line factions within the Palestine Liberation Organization.
Syria's relationship with Iran is also complex. Syria is Iran's only important Arab ally in the Iran-Iraq war. Yet Syria's often-frustrated efforts to free hostages held by pro-Iran factions in Lebanon, and growing pressures within Syria itself, suggest that Damascus cannot call the shots in Lebanon to the degree some in the US may have thought.
The US may be hoping to drive a wedge between Syria and Iran. But this prospect remains dubious. Washington does not have the leverage with Syria to effect such a change. And the reported recent meeting in Jordan between Iraqi President Saddam Hussein and Mr. Assad, bitter enemies over many years, signifies in itself no particular breakthrough.
In the end Syrian President Assad will do what he thinks is best for Syria's own interests. Damascus is an independent but important player in the Middle East. As long as the US enters any new relationship with its eyes open to such facts, it is less likely to make any mistake.