However much the outcome of the Camp David meeting may add to or detract from President Carter's reputation as peacemaker, still another test promises to weigh more heavily in the balance. That is the long-stalled SALT II treaty, which has Soviet and U.S. diplomats skittering back and forth between Moscow, Geneva, New York and Washington.

From an informed source, one who follows these matters closely from day to day, comes a report of yet another stall-or, rather, a series of stalls that will checkmate a treaty with all the fierce controversy it is bound to arouse from embarrassing the president as he prepares, at a low point in the polls, for reelection.

As one of the top White House officials puts it: "Everything we're doing has just one aim, and that is re-election." Opinions canvassed over the past year against this criterion show that a no-treaty result would not damage the president and might even help him, showing him as the strong man determined not to yield to Soviet blandishments.

On the other hand, a treaty rejected by the Senate - a probability today - would be most damaging. Around a defeat, even a narrow defeat, all the passions stirred by the last-ditch opponents, by the Pentagon and by those championing the Soviet dissidents would boil. Carter would be in the middle of a no-win contest.

So, as this report goes, there will be no treaty signed in 1978. In 1979 the New Hampshire primaries will be scarely more than a year away, and with Ronald Reagan pounding on the "defenseless America" theme it will hardly meet the reelection test for Carter to embrace Leonid Brezhnev at a treaty-signing ceremony.

Therefore, there will be no treaty next year, and certainly not in 1980. While that sounds wild, it matches the stern realities Carter faces.

There is only one question: Will the Soviet play this game of stall? The answer of the observers who see it this way is yes.

The Soviets have nothing to lose, and postponing any decision on the cruise missile and its range will cause neither side any pain. The repeated expressions of concern about Brezhnev's precarious health and his role as apostle of SALT is belittled by these observers. They cite the way the narrow controls within the Politburo consolidate quickly when a public leader has gone.

One indirect benefit is to rob such anti-SALT doubters and crusaders as Sen. Henry M. Jackson (D-Wash.) and Paul Nitze, former deputy secretary of defense, of an issue. For men like Nitze-a brilliant thinker who devotes most of his time to harpooning any further agreement with the Soviets that would have a chance of acceptance on either side of the divide-it is not so much an issue, in the customary political use of that word, as a way of life.

Without an agreement covering limits on offensive nuclear weapons, the buildup of the nuclear arsenals on both sides will continue. What is more important, the quality of those arsenals, the ever-more-lethal and devastating capacity of the weapons in those great mountains of death, will multiply.

Even those most dedicated to the need for a standoff agreement are beginning to have doubts. They are wondering if a point of no return has not been reached. They express something like despair over the nuclear abyss into which the world seems to be sinking.

There are those who will be deeply disappointed if Carter fails to come up with any form of limiting agreement. But so far as voter strength goes - that fundamental goal of reelection - they are not a major factor. While they might stay home on Election Day, it is hard to imagine them voting for a conservative Republican opposed to any and all trafic with the Soviet Union.

I readily concede that this may be far too pessimistic, Secretary of State Cyrus Vance has consistently held to the belief that a treaty will be signed, with SALT II putting an effective brake on nuclear weapons development.

Paul Warnke, chief negotiator and head of the Arms Control and Disarmanent Agency, has put months of effort into talking out the details of an agreement. He has done that knowing full well that the anti-SALT crusaders have made him a principal target.

So the prophets of despair may be suffering merely an end-of-summer gloom. The meetings between East and West still go on, and reports of the comings and goings of the negotiators have an optimistic note indicating that final details are being worked out. But for Carter, a treaty requiring a two-thirds vote for ratification by the Senate is a very high hurdle indeed.