Israel's normally contentious political leaders are agreed: The SAM-6 missile batteries moved into central Lebanon by Syria at the end of April have to go. That is the unequivocal message that Israel will present special United States envoy Philip Habib when he arrives today after visiting Lebanon and Syria.
In fact, informed Israeli sources say, barring an unexpected success by Mr. Habib in his mission to defuse the missile crisis, it is virtually a foregone conclusion that Israel will use force to remove them.
Israel's concern over the missiles -- a concern sufficient to risk war -- goes beyond the simple presence of a reported three batteries (36 missiles) of SAM-6's deployed south of the Lebanese Christian town of Zahle.
Israeli analysts say the introduction of the missiles violates an unwritten undertanding between Israel and Syria, valid since 1976, which was the quid pro quo for Israeli acceptance of an Arab-backed Syrian peace-keeping force in Lebanon.
Acceptance of this violation would, they believe, precipate significant changes in the strategic balance in the region.
By themselves, the three mobile SAM-6 batteries could probably be circumvented by Israeli planes with sophisticated jamming devices, these analysts say. Israeli acceptance of such a serious breach of a tacit understanding would be an invitation for Syria to take further steps. This might mean harsh pressure on Israel's christian allies in Lebanon such as the bombardment that precipated the present crisis.
It could involve the movement of more Syrian troops into Lebanon.
Or, most dangerous, it could lead to a Syrian buildup of an integrated air defense system in Lebanon, involving the introduction of more and varied types of missiles batteries, effectively closing off Lebanese air space.
Syria considers these missiles "defensive." It justifies the presence of its troops in Lebanon not only by the historical perception of the whole region as "Greater Syria," but by Arab backing -- now reportedly somewhat diminished.
But Israel -- which labels Syria, as well as its PLO allies in south Lebanon as occupiers usurping Lebanese sovereignty -- has insisted on Israeli rights to fly over Lebanon to aid the Christians and to attack PLO bases from which strikes into Israel originate.
The closure of Lebanese airspace would thwart this policy.
Finally, in the long-term strategic picture, the closure of Lebanese airspace could have an impact should Syria ever instigate a war of attrition on its current border with Israel, the Golan Heights. In such a case, say analysts, Israel would be denied the option of sweeping around the heights through Lebanon on the way of Damascus.
Although Israel is determined to get the missiles out, there is clear recognition here of the difficulties of confining military action to a 'searchable strike' to remove the missiles. Even if Israel aimed only at a restoraton of the status quo ante, the Syrian response is difficult to predict. The Israelis are confident that they could win a major or minor confrontation handily.
But Israeli officials concede that Syrian President Hafez Assad might be concerned more with problems at home or questions of Arab prestige than his own military losses.
He could press for a drawn-out conflict in order to downplay pressures from the Muslim Brotherhood at home to prove his mettle, or try to embarrass Egypt's President Anwar Sadat into abandoning ties with Israel. And it is unclear how -- or whether -- his Soviet allies would try to rein him in.
Perhaps because of their awareness of the risk, Israel is at present downplaying Syrian military movements and projecting a calm atmosphere without visible hints of prewar tension. Political sources here deny rumors that Israel has been reinforcing its troops on the Lebanese border.
But should Mr. Habib's efforts fail, Mr. Begin has said, "We will do what we have to do."