ON THE WAY to a smooth solution to the dispute over providing F15 fighters to Saudi Arabia, the administration got careless. Instead of just providing extra fuel tanks and bomb racks and compensating Israel in hardware and political assurances, it added five AWACS early-warning planes to the package, Why? Apparently because the Saudis asked for the planes -- to improve their defenses and to test the good faith, as they see it, of the new administration. Eager to enlist the Saudis in its "strategic consensus," the administration, not without hesitation, agreed. But it should have hesitated some more.

It's not always easy to draw a sharp line between enough and too much, but in this case it's not so hard. F15s will help give Saudi Arabia a defense capability and, perhaps no less important to it, a sense of American concern for its well-being. That's fine. The Saudis live in a neighborhood of sharks, and the United States needs their oil and friendship. But the AWACS planes, to be delivered in 1985, are different from F15s in several regards.

Those planes will provides an electronics capability, "putting Israel naked," that the Israelis do not possess and will not be able to match given the immense costs. They will erode significantly the qualitative edge on which Israel, with American approval, has relied in its defense planning, and will push Israel toward a return to a strategy of preemption. "With increasing frequency," writes the Jerusalem Post's Hirsh Goodman, surveying Israel's absolute and relative impoverishment and the flow of ultra-sophisticated arms to its oil-rich foes, "one hears about the desirability of going nuclear -- something that could not be talked about until a few months ago."

The real problem with AWACS, however, is one that has long plagued American policy in the area. The United States has drifted into using arms sales to satisfy political pressures or designs of the moment rather than to resolve the underlying Arab-Israeli split. For the AWACS deal is meant not only to draw Saudi Arabia into closer stategic partnership. It is meant also to dull Saudi protests that the United States is not pressing hard on the Israeli-Palestinian front. This puts the United States in the bizarre position of providing weapons that aggravate the possibility of war, even while it hangs back from diplomacy that might ease that possiblility. The diplomacy it hangs back from, moreover, is its own: Camp David. Saudi Arabia, with nothing to put in its place, has used its great influence to undermine this process in both its Egyptian and Palestinian aspects.

The Israelis, who have often benefited from the American readiness not to link arms sales to diplomatic cooperation, are poorly placed to complain about the Saudis now. Anyway, it is a decision for Americans to make. If diplomacy is in low gear while everyone waits for the Israeli elections at midyear, then let arms sales go into low gear, too. Progress toward an Israeli-Palestinian solution will not solve all of the United States' Middle Eastern cares, but it will certainly help. The Saudis should not have to be reminded that such progress will do far more for their security and nerves than will any new arms deal. A delay on an AWACS decision, moreover, will spare the administration the sharp defeat on this issue it is otherwise quite likely to incur on Capitol Hill.