FROM A NARROW diplomatic viewpoint, the Carter administration was right to slap Israel the other day. The new Israeli prime minister, Menachem Begin, and his foreign minister, Moshe Dayan, had indicated that they regard retention of the West Bank as non-negotiable. This suggested to the White House that the Begin government was deliberately shutting its ears to a message the Carter administration had repeated as recently as Vice President Mondale's speech of June 17. So the State Department was instructed (by the White House, and at the President's request, the way we understand it) to say that "no territories, including the West Bank, are automatically excluded from the items to be negotiated."

From a broad political viewpoint, however, the statement was unsatisfactory and possibly counterproductive. For instance, in return for territorial withdrawal and establishment of a Palestinian homeland, the Arabs were asked only to take "steps toward" normalized relations with Israel - a far cry from the real peace that Vice President Mondale had said would be Israel's prize. The tone of the statement was sharp and peremptory. It was as though Mr. Carter had deliberately set out to unify Israelis around their most rigid negotiating standard and to wink to Arabs that they need merely wait for Washington to squeeze Israel harder.

Mr. Carter has drafted, we believe, a responsible and promising approach to a Middle East settlement in which - though negotiations and by phases - Arabs would reclaim lost territory, Israel would gain a neighbor's acceptance and both would enhance their security. But the President does not always seem to realize that the boldness of his goals requires a matching sensitivity in tactics. The decisions he is demanding from Israelis and Arabs alike are so difficult that neither side can be expected to move ahead unless it is assured that the other is moving, too. That is why it is aunrealistic, unfair and unhelpful for the United States to nourish critism of Israel for territorial inflexibility while ignoring comparable Arab intransigence on the sort of normalization that the Israelis have in mind, and rightly so, when they speak of "real peace."

It was disingenuous of the President to convey at his news conference Thursday that he had had nothing to do with the earlier statement. He was right, nonetheless, to return to a more restrained and balanced track. That's where his country has to stay if it is serious about using its good officesin the achievement of a durable, comprehensive Mideast peace.