America's behavior toward Israel reminds me of the attitude of many mothers toward the savagery of their violence-prone kids. True, Israel may have behaved excessively in Lebanon, our officials tell us. But we have to understand that it has been picked on by bullies: deprived of security, disadvantaged by the fact of its existence in a sea of hostile neighbors and psychologically damaged by the Holocaust. Deep down, Israel always was a good boy.

And America's boy. The same America that finds it too costly to care for its homegrown hungry, jobless, uneducated and hopeless finds it not at all inconvenient to underwrite Israel's domestic and military budget to the tune of some $3 billion a year--$1,000 per man, woman and child in the whole country.

Not all the money we give Israel looks like a gift. Some two-thirds of it is accounted for, officially, as "sales" of military supplies and equipment. But as Thomas Stauffer of the Harvard Center of Middle East Studies noted in the Christian Science Monitor last December, there is less to the sales than meets the eye.

For example: "In fiscal 1980, $1 billion worth of foreign military sales were authorized for Israel's account. Immediately following the 'sale,' however, $500 million of the loan was canceled and the residual $500 million was added to the $7-plus billion the State Department estimates that Israel now owes the U.S. government. This debt involves grace periods of up to 10 years prior to any repayment. . . . (Israel) can service this debt only in the formal sense that installments are paid when due but are in fact funded through new U.S. aid each year."

There are other bookkeeping tricks, including military procurement contracts and grants, that we use to keep the Israeli economy--and the Israeli military machine--afloat.

The point is not that this country shouldn't be helping Israel, which, after all, has been an important ally. The point is that we had better recognize--as the rest of the world already does--that we cannot supply Israel's war machine or underwrite its bellicose policies without buying into its bellicosity.

Those were American planes and missiles and tanks that smashed into Lebanon, leaving thousands of dead and maimed civilians, women and babies, in their wake. At some point we will have to get beyond cheering that the Israeli invasion has proved the superiority of U.S. armaments over the Soviet-supplied arms that were unable to repel the blitz; get over our secret elation that the Palestine Liberation Organization has been reduced to impotence; and deal with the fact that weapons, supplied by us on the hard understanding that they will be used only for defensive purposes, have been used to slaughter innocents who were no threat to Israel.

Maybe Israel always was a good boy, whose only desire was for peace. But the American interest in a peace that results from accommodations between Israel and its neighbors is very different from the peace Israel is trying to purchase through the elimination of its enemy.

And for all the carnage our money and weaponry made possible, Israel's bloody course will not produce either peace for itself or justice for the Palestinians. Even accepting that the PLO is a terrorist organization committed to Israel's annihilation, the PLO is not synonymous with the Palestinian people whose homelessness Israel seems not to care about, though that is the principal source of the ceaseless unrest in that part of the world.

It would be hard enough to justify the invasion and continuing occupation of Lebanon if there were reason to believe that Israel, having vanquished the PLO, now intends to do justice to the Palestinians. It is impossible to justify it when it seems clear that the real object of the blood bath is to kill the Palestinians' dream of nationhood.

Israel, America's good boy, initially described its invasion of Lebanon as retaliation for the shooting, in London, of the Israeli ambassador to England. Then we were told the purpose was to clear a 25-mile zone in southern Lebanon in order to push the PLO out of rocket range of Israel. Now the purpose appears to be the conquest of pitiful Lebanon and the extermination of the PLO.

Maybe America, in the role of anguished mother, cannot persuade its violence-bent good boy from pursuing his bloody course. But she can at least stop furnishing the kid guns..