IN WORDS, ANYWAY, the Pentagon had it about right the other day in its briefing on the military links being constructed with Saudi Arabia. It said that the United States has been trying "all along" (since Afghanistan) to get into a position to offer reassurance and a credible defense to Persian Gulf Arabs; AWACS are part of that effort. But, the briefer added, "we have to walk a balance between what we would like to do and any confusion we could cause to the region if the military were to come out too strong." He was referring to the Saudis' reluctance, even as they seek protection, to be seen as an American tool.

Correct as these words are, they do not answer every question a responsible observer might have. On the available record, for instance, there is no reason to doubt the Pentagon's denial that a formal agreement has been made to prepare Saudi bases for American emergency use and to create a regional defense network. But these are long-avowed goals, and the chosen method is to pursue them without formal agreement if the Saudi imperative of discretion makes that necessary.

The administration says of certain grand-strategy discussions conducted by the two nations on the military staff level that they require a political imprimatur to make them real. But the memory of the Air Force's role in forcing the politicians' hand on AWACS is still vivid. And what did the Saudis take from those discussions, conducted as they were by a member of the royal family? There is an inherent tension between the American and Saudi ways of doing this sort of business. The potential for misunderstanding is high.

In the heady post-AWACS atmosphere, there is a tendency to attribute any questioning of American- Saudi ties to the pro-Israel lobby. This is wrong. Obviously the Israelis cannot be indifferent to the spectacle of Persian Gulf Arabs' acquiring tens of billions of dollars worth of the latest Western military technology; President Reagan granted this concern in the conditions he placed on the AWACS sale. But you don't have to be Israeli to ask, quietly, what will be the cumulative social and political effect of these transfers on Saudi stability.

The royal family's Saudi Arabia is not the shah's Iran. But the United States is making a tremendous investment there. It cannot afford to get careless again.