Somewhere along the way, the world seems to have discarded the principle of proportion. In the South Atlantic, the Falklands triggered a war that is likely to claim more casualties than the population of the islands themselves. In the Middle East, Iran and Iraq are slugging it out over who-knows-what and now Israel is deep within Lebanon, waging a war that is totally out of proportion to the events that triggered it.

It may be that we have become so accustomed to these bursts of insanity that they no longer have the ability to shock. But particularly when it comes to Israel and what it has been doing in Lebanon, the principle of an eye for an eye has been junked. The shooting of an Israeli diplomat in London (and maybe not even by the PLO) is followed in almost no time at all by an invasion of another country, the bombing of its capital and the risk of a wider war. There is something dreadfully out of whack here.

At the moment, the Israelis hold large hunks of Lebanon. They have bombed Beirut, stormed crusader-era castles, done lots of damage to the PLO and to innocent civilians, and it is very hard to explain why--what touched it all off. It is a tragic truth, of course, that the Israeli ambassador to England was shot by Arab terrorists, but that was the not the cause of the war. It was a pretext. The Begin government had been threatening to punch a hole into Lebanon for months before that.

It is true, also, that the PLO shelled the Galilee, forcing civilians into underground shelters, doing considerable damage and taking at least one life. But that shelling followed the bombing of Beirut. It did not happen just by itself but was, instead, a response to the Israeli escalation of the violence.

It is not hard to appreciate the Israeli position. Nothing in the Middle East happens in an historical vacuum. Jews and Arabs there have been (literally) slitting one another's throats since the anti-Jewish riots of 1929 in Hebron. It is folly to break off one episode and treat it in isolation or to ignore, for that matter, that with the exception of Egypt, none of the Arab states has deigned to made peace with Israel or even to recognize its right to exist.

But the PLO has been relatively quiescent lately. Israel holds it accountable for several attempts at infiltration from Jordan, occasional shelling of the Israeli-controlled buffer zone in Southern Lebanon, some mining of the same area, the bombing in Berlin of a cafe frequented by Jews and the shooting of two diplomats, one of whom was killed. In all, Israel counts 25 dead, 150 wounded in 250 operations--some of them of dubious PLO responsibility and some of them not involving Israelis. These incidents are not to be dismissed, but they do not warrant the bombing of Beirut, the invasion of Lebanon and the risk of plunging the world into war.

There was, in fact, mighty little provocation here. Israel for years has been an embattled nation, but that does not now give it some right to assert an exaggerated concept of defensible borders. The shooting of a diplomat, no matter how despicable an act, does not give Israel the right to reduce whole neighborhoods of Beirut to rubble. The alleged and, it seems, sporadic mining of the Lebanese buffer zone does not justify a full-scale invasion of another country. Israel has lost its sense of proportion.

In the strictest terms, this is no defensive war, but a war of opportunity instead. The Arab world is split 10 ways to Sunday and the Begin government saw a chance to move in, establish even more secure borders, and deal the PLO a punishing and maybe fatal blow. In terms of Realpolitic, these are understandable objectives. But that is not the same as saying that they are "right" or "moral" or will help in the long run to bring peace to the Middle East.

Maybe the ultimate tragedy of the seemingly nonstop war in the Middle East is that Israel has adopted the morality of its hostile neighbors. Now it bombs cities, killing combatants and noncombatants alike--men as well as women, women as well as children, Palestinians as well as Lebanese. In the region where an eye for an eye first linked proportion to justice, the concept has been scrapped. An eye no longer gets an eye, but the whole body as well.