THE COMIC OPERA imbroglio over the "discovery" of the Russian soldiers in Cuba has, if nothing else, dramatized the phoniness of the SALT debate.

The debate is phony in the sense that it is not about the things either its advocates or its opponents claim. Liberals have tried to sell the treaty as a step toward a more peaceful world; conservatives as a device by which the Russians can dominate the world. It is neither.

SALT II is not about arms reduction and mutual trust, on the one hand, nor about nuclear blackmail and strategic advantage on the other. Praised for what it cannot achieve and vilified for what it does not attempt, the treaty has been oversold by some and deliberately distorted by others. The general public hardly knows what SALT II is about -- and with good reason, for its meaning has become almost entirely symbolic.

First, let us clear away some underbrush. On its most pragmatic level SALT II is neither a panacea nor a giveaway. It is simply a deal that both superpowers consider to their mutual advantage. It will allow each to continue dissuading the other from attack without going bankrupt in the process. By so doing it makes it easier for both, under the umbrella of a nuclear standoff, to keep their allies in line and to intervene guardedly in the fringe areas of the Third World. SALT II, like a cartel's decision to divvy up markets in the name of price stability, is basically an arrangement to compete at a tolerable cost.

In one sense, nothing much will change if SALT II is ratified by the Senate. The Soviets will keep their army in Eastern Europe, just as we will keep ours in Western Europe. They will continue to meddle in Asia and Africa, just as we have been doing for decades; and they will send their ships into distant waters to demonstrate, like us, that they are supposed to be taken seriously. Client states will be rewarded with cash and hardware; neutrals will be wooed with the same. The great power game will go on pretty much as before. SALT II will simply free some resources for other, though not necessarily less lethal, purposes.

But if SALT II will not end, or even appreciably slow down, the arms race, it can prevent it from speeding up. It will reduce the pressure on both sides to build weapons that will not make them any more secure -- only a good deal poorer. In this sense it stabilizes the arms race by accepting the fact that, in the nuclear arena at least, both sides are equal. The quest for nuclear supremacy is ephemeral. Both sides have learned that the hard way. SALT II is an attempt to keep the potlatch within tolerable limits.

The arguments against SALT are two: first, that it will give the Russians a military advantage; second, that it will affect the ability and the willingness of the United States to defend its vital interests. These are serious objections if they can be sustained. They cannot. The current treaty, as the summer's Senate hearings conclusively demonstrated to all who were willing to listen, does not prevent the United States from building any weapons it seriously desires. This includes the multi-megaton Amtrak monster, the MX mobile missile, to which President Carter has given the green light. On the other hand, the treaty does put restrictions on the Soviets, such as limiting the number of warheads they can place on their giant MIRVed missiles. Without the treaty there would be no reason for the Soviets to accept such restraints.

So much for the military argument against SALT -- one which even the treaty's most vehement opponents are now downplaying. Instead, they are concentrating on what is essentially a political, and even a psychological, objection to the treaty. SALT, they maintain, could sap the nation's "will," soothe it into sloth and indolence, even, in the frenzied imagination of The Wall Street Journal's editorialist, allow the Russians to believe they could safely invade Long Island. SALT, in other words, even if harmless in itself, could lull us into a false sense of security.

This is, to be sure, a bit like arguing against fire insurance on the grounds that it would encourage homeowners to build bonfires in their bedrooms. But to meet this supposed danger the treaty's opponents, having shifted their line of argument, now demand a 5 percent across-the-board military buildup as the price for SALT.

Perhaps such a buildup is necessary -- at least for the purposes they have in mind. Perhaps not. In either case it should be debated on its own terms. With regard to SALT it is totally irrelevant. One's adolescent son may or may not need a Porsche to impress his chums and shame his rivals. But its relevance to his willingness to finish high school is tenuous indeed.

Thus it is that the arguments against SALT seem very odd -- odd, that is, until one realizes that they are not about SALT at all, but about the perception and the uses of American power. As Ben Wattenberg wrote so revealingly in Outlook a few weeks ago: "SALT may not be the ideal trolley car to board in order to pursue other demands. But it happens to be the only trolley car coming down the track right now."

Those "other demands" involve a big increase in non-nuclear forces, including aircraft carriers, a fleet in the Indian Ocean and an expanded army based on a reinstitution of the draft. To what end this military buildup? Here the scenario becomes vague. But clearly the objective is to regain to capacity, and the will, to intervene militarily in the Third World. Angola yesterday, Nicaragua today, perhaps the Persian Gulf tomorrow. There is no phrase more objectionable to SALT's critic than "no more Vietnams," and none they are so eager to see expunged from the American political vocabulary.

The Carter administration's willingness to build the MX missile and to approve a 3 percent increase in the military budget is designed primarily to assuage SALT's critics. Thus the treaty, whose virtues are hardly overwhelming, carries a very high price tag -- one so high, in fact, that several Senate liberals are threatening to vote against it. The problem with the MX is not only that it is exorbitantly expensive -- an estimated $30 billion at a time when Congress can find money for little else except its own raise -- but that it is a first-strike weapon. The MX in effect undercuts the central premise of arms control: that the emphasis must fall on deterring nuclear war rather than "prevailing" after one. With the MX wagging the tail of SALT, the way is now open for adoption of the strategy that SALT's opponents have favored all along: a counterforce capacity and the ability to fight "limited" nuclear wars. Ideally these opponents would like the MX and the arms buildup without SALT. But if they get them, SALT itself will become irrelevant -- irrelevant because it is innocuous.

Thus it can be seen that the furor over SALT is phony because the treaty is not the problem. It is not so important in itself to merit the agitation it has provoked. Its significance is almost entirely symbolic. Conservatives see it as an escalator to a non-nuclear military buildup and an end to the "no more Vietnams" syndrome. Liberals think it will slow down the nuclear arms race and allow the United States to concentrate on its economic priorities. They may both be reading more into SALT than it deserves. But when one is desperate, one takes whatever trolley car comes along.

SALT is, of course, symbolic in one other sense. It ratifies Soviet military equality with the United States and acknowledges that in this realm we are no longer the undisputed Number One. SALT did not, of course, create this condition. But by acknowledging the undesirable, it seems to sanction the intolerable: that Americans live in a world they cannot control and are confronted by adversaries they cannot intimidate through force of arms. Pax Americana was a nice ride while it lasted, but it is now over.

SALT II -- which was, after all initiated by Richard Nixon and Henry Kissinger -- is a victim of bad timing. It comes in the wake of the defeat in Vietnam, reversals in Angola, Ethiopia and Afghanistan, the collapse of the shah of Iran, the triumph of OPEC and the collapse of the dollar to the status of a funny-money currency. That none of these events had anything to do with the supposed "decline" of American military power does not make their impact any less disturbing. People are anxious. They do not like a nuclear arms race, but neither can they abide seeing events slip out of contol. Consevatives play on these anxieties. They talk about "national will" and "power" as though they were talismans that would make everything right again.

Whether or not SALT II ultimately clears the Senate, it has already -- like the Pamama Canal treaty last year -- been inflated out of all proportion to its significance. The symbol has become everything. Its ratification may not achieve much, but its defeat would be a stunning victory for those, seething with an unfocused frustration and resentment, who seek to rekindle the Cold War.