HERE WE GO, off on another bruising, careening battle over the sale of arms to Arabs. This time the would-be recipient is Jordan, whose king, his appetite apparently whetted by the administration's secretary of defense, indicates that he is ready to put in for a new matched set of American anti-aircraft missiles and combat airplanes. Does he "need" the gear? Should he be sold it? King Hussein says yes; the Israelis say no. To catch the argument, it is almost enough to play the AWACS record again.

The argument has to do in the first instance with the military balance, which, in the Middle East, is a tenuous and shimmering equation measuring states of mind as much as forces and capabilities. Over the years, the Israeli effort, to which President Reagan has just formally recommitted the United States, has been to maintain a qualitative edge. The Arab effort, to which Secretary Weinberger has apparently committed the United States at least in the matter of Jordan, has been to dull that edge.

The Jordanian military can make a perfectly good case for the equipment being sought. Unfortunately, the new stuff, if acquired, will almost certainly diminish the discretion that kept Jordan out of the last war and spur Israel to attack Jordan preemptively in the next. The forces driving Jordan to make its request have little to do, strictly speaking, with military security.

With what, then? With politics. Not alone in the Arab world, Jordan defines the Middle East problem as the product of excessive American support of Israel. For Jordan, the requirement is not to build the forces to win a war--that's regarded as foolish and self-defeating. The requirement is to loosen a little--no one expects a lot--the American embrace of Israel and then . . . Actually, the Arabs don't have a "then," a plan. But they are eager to set Americans and Israelis at odds. They do this by asking the United States for arms. Israel always objects, but the Arabs insist, and eventually the United States at least partially relents. This administration is not the first to be whipsawed by this tactic.

Something better is available. The curse of American policy in the Mideast, through successive administrations, has been to substitute arms deals for an all-out diplomatic effort to close the Israeli-Palestinian breach. Mr. Reagan continues this appalling tradition. As long as he does, he sets up the United States for just such raids on its arsenal as King Hussein is undertaking now.