FOR the past five months, Syrian President Hafez Assad has made a series of audacious moves that Israel's military and civilian leaders have been trying to interpret before determining how best to respond. In December, Mr. Assad moved SAM-8 missiles into Lebanon's Bekaa Valley and placed longer-range SAM-2 missiles on Syrian soil, but deployed to impede Israeli air activity over the Bekaa. After sharp Israeli warnings, the mobile missiles were withdrawn. The SAM-2s remain.
In March, Syria began digging trenches and building fortifications able to accommodate a full combat division close to the old ``red line'' positions in the Bekaa from which Syrian forces had been pushed back by the 1982 Israeli invasion. Israel has long said it would not permit a Syrian return to the old red line, a warning repeated via US Ambassador Richard Murphy on his last visit to Damascus. Assad dismissed the caution with the claim that Israel was preparing for aggressive war against Syria. Work on the fortifications has continued.
Throughout the period, Syria has maintained and improved its position in the Golan Heights, to the point where it could now field nearly five combat divisions, Assad having threatened in March to retake the heights by force should diplomatic efforts to retrieve them fail.
Throughout the period, too, Syria has been unusually active in its sponsorship of terrorism directed at Israeli targets abroad. While most of the public focus was on Libya following the December attack by members of the Abu Nidal faction on El Al airline counters in Rome and Vienna, no one remotely familiar with Abu Nidal's real source of power looks anywhere but Damascus and the license he enjoys to train and house followers in the Syrian-controlled Bekaa.
It has not been military weakness or a failure of nerve that has kept Israel from responding militarily to these assorted provocations. Rather, an unusually active debate has been occurring within the country's military and political communities trying to get a more precise fix on what Assad is up to.
To oversimplify only slightly, let us identify three schools of Israeli thinking:
The defensive school. This group, which includes Prime Minister Shimon Peres and Defense Minister Yitzhak Rabin, regards the Syrian position as weak; Assad's moves as essentially defensive or -- in the case of his sponsorship of terrorism -- desperate; and a bold Israeli response as both costly and unnecessary.
This group sees Israel's Golan Heights position as impregnable. Moreover, many in this group contend that it is in Israel's interest to see Syria establish a strong position in Lebanon, since only when order replaces chaos will Israel's northern frontier be truly quiet.
The Lebanon school. Led by Yehoshua Seguy, the former chief of military intelligence, members of this group see the establishment of a Pax Syriana in Lebanon as the great unfinished task of Assad's reign. They say that following Israel's withdrawal, Assad sought to establish Syrian hegemony by remote control and, having failed, is now laying the groundwork for a substantial Syrian military intervention.
This group believes that while it might be to Israel's short-run convenience to see a stable Lebanon, the establishment of a hostile power on the northern Israeli frontier could prove fatal.
Mr. Seguy argues that Israel would be forced to intervene to prevent a Syrian takeover of Lebanon and has thus been sending Damascus the wrong signals by curtailing its air operations in the Bekaa and letting terrorism go unpunished.
The Golan school. Led by Ariel Sharon, with much support in the Israeli military establishment, this group sees the Golan Heights and eventually all of Israel as part of Assad's design and believes that so long as Syria is permitted to move toward military parity and Syrian aggression remains unchecked, Israel falls deeper and deeper into jeopardy.
While not urging an immediate preemptive strike, Golan-school adherents clearly have a shorter fuse for tolerating Syrian adventurism and are less bothered by the prospect of Soviet intervention, which they regard as highly unlikely.
They feel that any display of Israeli indecision is unfortunate.
They contend that Israel should have held its position in Lebanon at the Awali River line, should in no event accept the further spread of Syrian power in Lebanon, and must respond unambiguously to all terrorist provocation.
Assad is thus walking a dangerous line among two policy schools that would have already responded to his recent moves with considerable military force and a third school, which can be considered ``dovish'' only in the unique spectrum of Israeli military thinking.
Among those who should today be thankful that the London El Al plane was not blown from the sky, Hafez Assad is perhaps first on the list.
C. Robert Zelnick is ABC News chief correspondent in Tel Aviv.