On the day that Israel signed a troop withdrawal agreement with Lebanon, Defense Minister Moshe Arens was in eastern Lebanon, at an Israeli Army outpost near the village of Ein Zachlata. There, in a makeshift headquarters building, the defense minister addressed about 40 paratroopers and tank crew members, young Israelis fighting their first war against an Arab enemy.

"Maybe this is a historic day," he said of the agreement being signed in the Beirut suburb of Khalde May 17. But, Arens added, "no one knows for sure, about this or many things in the Middle East."

A year after the Israeli Army stormed across the Lebanese border at the start of "Operation Peace for Galilee," Arens' curiously ambivalent tone probably comes as close as any to matching the mood of the country concerning Israel's most controversial war. Sharp divisions remain in Israeli society over the goals and conduct of the war, although it is easy to exaggerate the extent of domestic dissent.

A majority of Israelis still clearly support the immediate goal of the invasion--the destruction of the Palestine Liberation Organization as a hostile military and political presence along Israel's northern border. Still, the political consequences of the destruction of the PLO's privileged position in Lebanon have become the paramount advantage created by the war.

But as casualties have mounted--six Israeli soldiers have been killed in Lebanon since the signing of the troop withdrawal agreement--and with no sign that the Israeli Army actually will leave Lebanon anytime soon, the first anniversary of the invasion has become a time for sober measurement of the gains to Israel and their cost.

Was it, is it even now as sporadic fighting continues across the border, worth it, many Israelis ask themselves. Was it worth the cost in lives and suffering--490 dead Israeli soldiers, 2,751 others wounded, not to mention all the civilian casualties in Lebanon last summer?

Many Israelis view with dismay the internal divisions the war sharpened and brought to the forefront, divisions symbolized by the fate of Emil Grunzweig, a soldier who served in Lebanon, came home to protest his government's policies and was killed by a hand grenade tossed in the midst of a peace demonstration 100 yards from the office of Prime Minister Menachem Begin.

Was it worth the damage to Israel's image and international standing and the strain it caused with Israel's most important ally, the United States? And, Israelis ask, did it cause the deepened freeze that has fallen on its relations with Egypt, the largest and most important of the Arab countries and the only one formally at peace with the Jewish state?

In terms of lost lives, "Operation Peace for Galilee" can be viewed as a poor trade, if such things could be quantified. For a full year before the invasion, not a single Israeli had been killed as a result of PLO actions emanating from across the border in Lebanon. In the four years between Israel's 1978 invasion of Lebanon and last summer's war, Israeli deaths that the Army classifies as resulting from "terrorist actions" did not approach the 490 killed in the war.

But Israel did not invade Lebanon solely with the announced goal of freeing its northern communities from the threat of PLO attack. Its war aims were far more ambitious. Some of its goals have been achieved, others hang in the balance.

The PLO has been destroyed as a functioning military entity on Israel's northern border. Despite the large amount of arms the Palestinian guerrillas accumulated, they never posed a credible military threat to Israel, but they will be a long time, if ever, getting back to where they were a year ago.

The irony of this, however, is that Israel's northern border may be no more safe as a result. Israel recognized this in the troop withdrawal negotiations with Lebanon in insisting on a wide "security zone" in southern Lebanon where its own soldiers would continue to play a role in preventing infiltration by Palestinian guerrillas. Small bands of guerrillas bent on killing may in the end pose a greater threat than a PLO mini-army that had much to lose by risking open incursions across the border from its base in southern Lebanon.

The PLO was also destroyed as a political entity in Lebanon--"a state within a state" in the words of Begin and other officials. This political objective of the war was why, Israeli officials say, they had to send their army all the way to Beirut and lay siege to the Lebanese capital, even with all that cost in terms of Israel's image and relations with the United States.

The scattering of the PLO throughout the Arab world and the internal dissension that has recently afflicted the organization are seen as byproducts of the war.

"Lebanon was important politically to the PLO," a senior Defense Ministry official said. "It was where they trained their kids for the revolution. That's over now."

In retrospect, the political goals, and not the military objective of safeguarding the northern border, were paramount in "Operation Peace for Galilee." It is on this basis that Israeli officials today ask their compatriots to judge the outcome of the war.

"What we have achieved in the agreement with Lebanon is first and foremost a change in the political situation, and I think there is not sufficient awareness and understanding among us on that change," Arens said in a published interview just before the accord was signed.

"We have all reached the conclusion that a security zone in southern Lebanon--almost regardless of its depth--does not solve our problem and does not release us from having to go out again and again on similar combat operations," he continued. "What was necessary and essential for us was a political change--to put an end to the state of war between Israel and Lebanon that existed for 35 years, since the establishment of the state of Israel."

From its birth in 1948, Israel has fought its wars with two primary goals: the immediate goal of survival, and the longer range objective of acceptance and legitimacy as one of the nation-states of the Middle East. After the war in Lebanon, the first goal is more than ever secure, at least in the near term--Israel is the undisputed military power of the region.

But the larger objective of political acceptance by its Arab neighbors remains elusive. A second Arab country, Lebanon, has joined Egypt in reaching a formal accord with Israel. But it is not a peace treaty, and Lebanon is so fragile that no one dares predict how long it will hold up or whether it will lead to anything more meaningful. The PLO is militarily smashed and in political disarray, but the "Palestinian problem," in both the occupied West Bank and Gaza and throughout the Arab world from which Israel seeks legitimacy, remains as acute as ever.

The war may have "bought Israel some time," in the words of one observer here, but whether it will be seen as achieving much more than that is an open question. Gone are the predictions, voiced by Begin last summer as the Israeli Army surrounded Beirut, that the war would usher in an era of "40 years of peace." In their place are the much more measured words of Arens:

"We have created a basis here which creates chances that we will indeed achieve what we set out to achieve. No one can say more than that at this time." insisting on a wide "security zone" in southern Lebanon where its own soldiers would continue to play a role in preventing infiltration by Palestinian guerrillas. Small bands of guerrillas bent on killing may in the end pose a greater threat than a PLO mini-army that had much to lose by risking open incursions across the border from its base in southern Lebanon.

The PLO was also destroyed as a political entity in Lebanon--"a state within a state" in the words of Begin and other officials. This political objective of the war was why, Israeli officials say, they had to send their army all the way to Beirut and lay siege to the Lebanese capital, even with all that cost in terms of Israel's image and relations with the United States.

The scattering of the PLO throughout the Arab world and the internal dissension that has recently afflicted the organization are seen as byproducts of the war.

"Lebanon was important politically to the PLO," a senior Defense Ministry official said. "It was where they trained their kids for the revolution. That's over now."

In retrospect, the political goals, and not the military objective of safeguarding the northern border, were paramount in "Operation Peace for Galilee." It is on this basis that Israeli officials today ask their compatriots to judge the outcome of the war.

"What we have achieved in the agreement with Lebanon is first and foremost a change in the political situation, and I think there is not sufficient awareness and understanding among us on that change," Arens said in a published interview just before the accord was signed.

"We have all reached the conclusion that a security zone in southern Lebanon--almost regardless of its depth--does not solve our problem and does not release us from having to go out again and again on similar combat operations," he continued. "What was necessary and essential for us was a political change--to put an end to the state of war between Israel and Lebanon that existed for 35 years, since the establishment of the state of Israel."

From its birth in 1948, Israel has fought its wars with two primary goals: the immediate goal of survival, and the longer range objective of acceptance and legitimacy as one of the nation-states of the Middle East. After the war in Lebanon, the first goal is more than ever secure, at least in the near term--Israel is the undisputed military power of the region.

But the larger objective of political acceptance by its Arab neighbors remains elusive. A second Arab country, Lebanon, has joined Egypt in reaching a formal accord with Israel. But it is not a peace treaty, and Lebanon is so fragile that no one dares predict how long it will hold up or whether it will lead to anything more meaningful. The PLO is militarily smashed and in political disarray, but the "Palestinian problem," in both the occupied West Bank and Gaza and throughout the Arab world from which Israel seeks legitimacy, remains as acute as ever.

The war may have "bought Israel some time," in the words of one observer here, but whether it will be seen as achieving much more than that is an open question. Gone are the predictions, voiced by Begin last summer as the Israeli Army surrounded Beirut, that the war would usher in an era of "40 years of peace." In their place are the much more measured words of Arens:

"We have created a basis here which creates chances that we will indeed achieve what we set out to achieve. No one can say more than that at this time.