The buildup for Sunday night's televised foreign-policy debate between Ronald Reagan and Walter Mondale was stupendous, a kind of Khachaturian frenzy. It put me in mind of those bygone days when America breathlessly awaited the scheduled program on which some contestant or other would have a chance to win an unimaginable amount of money. Or was it more like anticipation of the program on which a sleepless nation would finally learn who shot J. R.? Never mind. The point is that our sense of drama was disappointed in this case, unfulfilled. Why?

I think the answer is that everyone was busy looking for the wrong outcome and ignoring the unique set of rules and delicacies that hedge a confrontation between incumbent and challenger on this particular subject. For two weeks various commentators had been telling us which mean, gotcha-type questions needed to be sprung by their candidate, who must say what to score a knockout blow. Reagan must stage a comeback, we had been advised; Mondale must hold his own and so forth.

Well, in certain terms both of those things happened. But not by virtue of any bashing or no-holds-barred assault. For in truth, it was a whole other set of skills we should have been looking for. And these skills, just like the implicit rules, make a knockout punch not only impossible, but also probably inadvisable. I think it was no accident, in other words, that although both candidates were tough, both were also careful. They were being -- and trying to be seen as -- statesmen. That was what the encounter was about. It's not exactly the sort of exchange that encourages folks in the audience to holler "Kill, Bubba, Kill!"

The terrain is especially treacherous for the challenger, who must manage to suggest that the country is in trouble and/or danger and that the incumbent's policies are to blame, as Mondale did -- without seeming to bad-mouth the country, take the enemy's side or undermine the nation's leader. People are much more tolerant of what you call a president in a fight over the economy than of what you might say about him as the -- yes -- commander in chief. The incumbent, for his part, is bound to end up defending things -- foreign-policy setbacks and even some disasters -- for which there is no very good defense.

To some extent all this has become highly stylized. When it comes to attacking and defending policies involved in protection against terrorist attack, for example, you could take what Mondale has been saying about our negligence in Lebanon and with a few word changes get exactly what Reagan was complaining about in his 1980 debate with Jimmy Carter. As the challenger four years ago Reagan had not reckoned with what happens to your plans when you are faced with the realities of governing, especially those of presiding over and activating huge, complex and inherently recalcitrant, willful bureaucracies. Who authorized and wrote that damned CIA- killer manual anyway? Who urged putting the Beirut Marine barracks where they were? What exactly is it that he has signed onto in the so-called Star Wars enterprise? These things are always hard to be precise about, but Reagan, it seems to me, is more out of touch about them than his predecessors were about comparable matters.

So he had to be pretty defensive on some issues, and he also self-evidently felt he must move more toward the center on war-and- peace issues, to diminish some public anxiety about him as a bombslinger. The kinds of inspirational, prose-poem things he says on this subject will strike many as vague and unexceptionable, but it is worth remembering that Reagan's own political core constituency is very hard on him on this subject and his own government is torn on his defense and East-West policies. So he was playing to two quite different and quite incompatible audiences: the right- wingers who think he is being manipulated by softies in the White House and the undecideds who are afraid of him on the bomb. I think he had to speak almost exactly as he did.

Mondale had the really tough assignment, which is why I would award the evening to him. Traditionally the challenger charges the incumbent with weakening the country (Kennedy, Carter and Reagan as outsiders in debates all did this). But Mondale could hardly call Reagan a patsy for the Russians. Except that in a rather sophisticated and artful way he did. I don't just mean the talk about not promising to share the technology associated with war-in- space plans. I mean his returning again and again to the command-and-control questions, the matter of being informed. It is here that Reagan is notoriously weak, and the postmortems on his first debate performance -- replete with all those complaints about how cruel it had been to try to stuff his mind with facts and how he should be allowed to "be Reagan" and revert to sermonettes -- didn't exactly help.

Mondale, of course, also had a direction to move in: he needed to deal with the charges made by Reagan and Co. that he was weak, an appeaser. He did this very skillfully, I thought, without sounding like a sudden convert, leaning always to the tougher side of the policy he espoused, getting in well-deserved clops at the Russians whenever the opportunity arose.

Dean Acheson, writing about American foreign policy and American politics, observed that two large home-grown mistakes on the subject proceed from some people's thinking that power is inevitably a function of physical force and others that it is a function of morality. The gun people and the prayer people make fairly terrible international leaders, and their arguments tend only to mislead and inflame a public that depends on them. American power, no matter how large our arsenal, is circumscribed (as the Ronald Reagan of Lebanon must now know); and it also requires much more than high-minded thoughts, as Mondale concedes. Each man seemed to me, the other night, to be acknowledging as much, to be trying to move toward a more balanced position. Both had come from another place. Both were trying to show that they were "safe," worthy leaders in these great matters of war and peace. Both, in short, were trying to talk us into something we were a little hesitant about. I found Mondale the more convincing.