A couple of months ago, the military affairs writer for the Jerusalem Post, Hirsh Goodman, abandoned tanks and missiles and tried instead to explain Rabbi Meyer Kahane, the Israeli parliament's notorious Arab hater. Kahane, Goodman wrote, is not an Israeli creation, but an Arab one. He's what you get after 37 years of Arab hostility toward Israel.

Goodman was explaining, not justifying, and it is good that he recognized the distinction. It is, in fact, a distinction being pressed into service when it comes to what Israel is doing in Lebanon -- why it's blowing up homes, making mass arrests, terrorizing the civilian population and turning parts of the country into a police state. As with Kahane, you can explain, but you cannot justify.

The explanation begins with the recent suicide attack in Lebanon in which 12 Israeli soldiers were killed outright and another 14 wounded. That incident brought to 126 the number of Israelis killed since Palestinian guerrillas left Beirut in September 1982. All in all, Israel's invasion of Lebanon has cost it 634 dead -- casualties of Vietnam war proportions for a country Israel's size.

But numbers are, well, numbers. They do not tell you that one of the dead was the only child of Holocaust survivors, people who clawed their way out of the death camps, managed to get to Israel, lived through maybe four wars -- and then lost their only child in some stupid operation in Lebanon. The numbers do not tell you about a lieutenant who got married last summer and has one kid on the way -- none of the little tragedies carried on the inside pages of the Israeli newspapers.

And so you can understand -- can't you? -- the fury with which Israel strikes back. You can also understand the terror of the troops, their fright when night falls, how scared they must be to move about in a population that has grown to hate their guts. Worse yet, the new enemy is a fanatic. The PLO was tenacious, often brutal, but it did not go in for suicide attacks. How can you fight someone who does not even value his own life, never mind yours?

But that is all explanation. There remains the matter of justification, and that is out of reach. Israel was wrong in invading Lebanon, wrong in staying and wrong in not instantly withdrawing. It might even have converted Lebanon from an enemy in name only to a real foe. The Shiite Moslems, some of them fundamentalist zealots, have discovered both their numbers and their strength.

The Israeli government, an entity with the divisions and pettiness of an academic senate, says its troops will be out of Lebanon by September. The Labor Party would like to leave sooner; Likud later. The result is a compromise -- a staged withdrawal designed to show that Israel cannot be pushed around. It has installations to dismantle. It has strategic concerns. It sticks to its plans. It will not lose face.

As a result, it loses its moral standing. Everything is explained -- the need to retaliate, to appear strong -- until it becomes clear that what you're hearing is a litany of excuses for inaction. Israel just ought to get out of Lebanon. Then no one will have to explain anything.