SOME OF THE Arabs have started something very silly and self-defeating. They want to kick Israel out of the United Nations system. Last month, Israel's credentials were rejected by the International Atomic Energy Agency. As early as today the International Telecommunications Agency may vote to exclude Israel. A week from today, the Israeli question is to come up in the General Assembly.

It should go without saying that it is a bad idea to remove individual members for political reasons from institutions whose chief reason for being is their universality. It runs against sense, principle and the United Nations Charter. Politically, moreover, it is stupid. To gang up on Israel in this way mocks the implication that most Arab states recently went to some lengths to convey, at Fez, that they are finally ready to accept Israel. The campaign has the effect of bringing the United States and Israel together at precisely the moment when the Arab strategy is to pry them apart.

How do the Arabs come to act in a manner that makes them a laughingstock? At the Assembly, Iraq and Syria launched the question. The "moderate" Arabs were unenthusiastic but flabby, and found themselves under pressure to promote it. It is said now that Iraq and Syria have thought twice but fear to back off because then one of the crazies, like Libya, may grab the flag and embarrass them, or Iran may grab it to embarrass Iraq. Such is the majesty of multilateral diplomacy.

The United States had hoped the thing would peter out. It didn't, and so over the weekend Secretary of State Shultz issued a strong public warning that Washington would end its participation and funding in any branch of the United Nations, the General Assembly included, that ousted Israel. The thought is that his pledge gives sensible members of the world body the ammunition they need to prevail.

Congress is already on record as favoring the firm policy Mr. Shultz presented. His position not only serves the requirements of American diplomacy in the Middle East. It is also the only position consistent with the strong American interest in making the United Nations a more effective instrument for world peace.