QUITE A COUNTRY, Syria, as Secretary of State George Shultz has now seen for himself. The Lebanese government makes and the Lebanese parliament accepts an agreement with Israel on the latter's withdrawal from southern Lebanon. Syria, declaring that the agreement violates Lebanon's sovereignty, refuses to allow it to go into effect. It is in a position to enforce this decision because its own troops are in eastern Lebanon. The government of Hafez Assad in Damascus simply does not admit the Lebanese have rights in their own country.

The best guess about President Assad is that he enjoys and perhaps needs being seen in a posture of defying the United States. Certainly, he looks arrogant for depriving the Lebanese of their chosen policy. He also looks foolish for failing to take the opportunity to draw Washington into talks on the other matters that one might expect to interest a responsible Syrian government such as: removing the Israeli guns that cover Damascus, or retrieving the territory lost to Israel in 1967, or getting down to brass tacks on the Palestinian question.

Secretary Shultz has chosen to look ahead to another, brighter day in Syria when the Syrian government becomes more approachable--no public recriminations with Damascus. He must now decide, however, how to cope with Israel's intention, in the absence of a joint withdrawal with Syria, to pull its forces back to a line where fewer Israeli casualties will be incurred.

The Lebanese fear such a "redeployment" will be not a way station to complete withdrawal but rather a prelude to a more permanent occupation. To preclude that possibility they threaten to cancel the Israeli-Lebanese agreement, which, as imperfect as it is, happens to be George Shultz's particular achievement. That is the knot he must try to untie in his stop today in Israel.

The Arabs said the key was to get Israeli consent to leave Lebanon. The United States got Israeli consent, on terms accepted by the Lebanese, and now Syria has gone back on its part of the deal. Few in the area are likely to shed tears to see Israel in the Lebanese quagmire: the Israelis made a terrible mistake by going up to Beirut and engaging the Syrian army, and now they are paying for it. But perhaps it will occur to the Arab states, if not to Syria, that one of their own--Lebanon--is paying more.