THE NEW YORK TIMES had it just right the other day in likening the current politics of SALT to a night at the opera -- all that rising, voluble emotion but no sign of the accords, so that it was "virtually impossible to follow the story." It is of course true that a lot has been made known about what is likely to be in the SALT II accords, but the fact remains that the country -- with the encouragement of the administration and many congressional figures -- has already begun a pretty slam-bang debate about whether the unseen and unachieved agreements should or should not be approved by the Senate.

The first thing this tells you is that some people are so fixed in their biases and predispositions that they are ready to argue for and against without benefit of the documents they are arguing about. But it also tells you something else: that the SALT II debate concerns much more than the agreements themselves. Whatever Jimmy Carter's negotiating team comes up with and whatever the president himself decides to recommend will be almost secondary to the national argument over the U.S.-Soviet strategic relationship and the defense obligations that implies, which will be the context in which SALT II is disposed of by the Senate.

At the crudest level what we will be witnessing will be little more than the familiar bargaining that always accompanies these arms-control deals. Administrations have long since learned how to buy the support of the reluctant with commitments to the pursuit of various weapons systems. The partial test ban treaty was achieved with a pledge to step up underground nuclear testing; SALT I came with a commitment to Trident among other things; SALT II, as it now seems, will be approved, if it is, with the aid of some kind of commitment to the MX missile, a new version of the Trident missile, a stepped up civil-defense program and a variety of other undertakings.

At some point in these domestic tradings, however, the lines may begin to cross: The price of approval of an agreement can get so high that it sharply diminishes the value of the agreement itself. This is one of the traps the president needs to beware of as he cranks up the campaign to win approval of the accords. His damping down of the enthusiastic $2 billion noises coming out of the administration on civil defense may represent a welcome turn in this direction. But there is another, deeper and equally self-defeating trap: The lavish trading can make an administration look unserious, phony, weak and mainchance minded to precisely those persons it is trying to win over. And this is the impression most likely to doom an attempt to get approval for an arms-control agreement, since such approval rests in large part not on the details of the accords themselves, but rather on the perception of the integrity and will of the administration that is promoting the accords.

Here, we reach Jimmy Carter's obligations and his dilemma. Never mind all that selling-of-SALT promotion among the groups and the subgroups -- truckers for SALT, senior citizens for SALT, SALT for women, SALT for men, SALT for sheep and goats. What the president has also to sell is himself: his constancy and his capacity to manage a new SALT agreement. To win the requisite votes he will have to win the confidence of a middle group of senators, leaning slightly away from the accords, that SALT II fits into some hardeyed, coherent and unsentimental reading of U.S. security interests whose implications Mr. Carter is willing to pursue.

You do hear a lot about a "new" Carter nuclear strategy these days, talk that the administration is upending the old wisdom of "mutual assured destruction" and moving toward some kind of "counterforce" posture. But these are the old buzzwords and what they allude to is, in terms of current weaponry and current international relationships, already obsolete. The question is whether the talk reflects merely the recognizable bartering and trading with the "hawks" that traditionally precede the introduction of an arms-control agreement, or whether it represents a genuine effort to bring current military policy and planning into phase with current military reality. Nuclear strategies are not sacred and cannot be immutable. But the great guiding principle of strategy -- namely, deterrence of nuclear war -- is both sacred and immutable, and the test of a SALT agreement, as well as the test of any new weapons or strategy the administration argues for, must be their capacity to serve this end. Forget the fixed positions and the ten-years-out-of-date pieties about this weapon's benign nature and that weapon's special threat. Too much has changed for that. You will be able to judge the seriousness of both the administration and its opponents in the debate precisely by the degree to which they force the SALT discussion into the context of this larger approach to U.S. -- Soviet nuclear relations.