To ratify or not to ratify.

TO RATIFY OR NOT TO RATIFY?

IT LOOKS as if Ronald Reagan will sign an arms-control deal with the Soviets this year, one that would eliminate short- and intermediate-range nuclear missiles from Europe. But it is less certain that the Senate will ratify such a treaty before Reagan's term is over.

Fifteen years have elapsed since the Senate ratified a weapons treaty. "It may languish in the Armed Services Committee the way SALT II did in '79,' says the Heritage Foundation's national-security analyst, Jim Hackett. "You can't verify small, mobile missiles --either the existence or the number of them.'

The State Department thinks otherwise. "Verification would be greatly simplified, since we're talking about an entire class of weapons,' says a State official. But will the Soviets even agree to "simplified' on-site inspection by U.S. Government officials? In the past, it is true, U.S. scientists have been allowed to put seismic monitors on Soviet missile test sites in the Urals, but that practice was highly limited.

Also, as many conservatives in Washington point out, the Soviets could put enormous pressure on the U.S. for the same degree of access, and if the U.S. were to agree, our nuclear secrets might be exposed to hostile eyes. Yet, if we were not able to monitor the Russians, they would surely indulge their inveterate penchant for cheating, and would merely hide their missiles instead of scrapping them. Were that the case, the U.S. would either 1) be forced to keep its own arsenal hidden, or 2) find itself at a military disadvantage. The President's special arms-control advisor, Edward Rowny, may well be correct: "The Achilles' heel of any arms-control agreement is verification.'

Senators are even more concerned about another issue, viz., without a full range of nuclear weapons deployed, what would happen to deterrence? A lot, says ex-NATO Commander Bernard Rogers. "We don't have a credible deterrent,' Rogers told me succinctly, "because our conventional forces cannot deter.' The Warsaw Pact is ahead of us 3 to 1, Rogers explains; hence the Administration (with the cooperation of the Allies) will need to convince the Senate that, minimally, a workable plan exists to diminish this disparity. So, for some senators, one condition of INF ratification will be that the NATO Allies promise to kick in more for defense.

NATO's residual nuclear deterrent will also undergo senatorial scrutiny. Eliminating land-based medium- and short-range missiles voids one weapons category, but there are "still left U.S. tactical aircraft,' says a Hill arms-control aide. Also, senators will want to take a close look at the impact of an INF treaty on ICBMs and space weapons.

Working through this thicket of issues may delay Senate approval, but probably not block it. "If a reasonable superpower agreement is reached,' says a Hill aide close to Les Aspin, "an awful lot of liberal Democrats who usually do not support Ronald Reagan will back him because they have such a yen for an arms-control deal.'

As for Republicans, adds the aide, "many who are committed to Ronald Reagan--but oppose arms control--will cross their fingers, hold their noses, and vote for the deal in order to ensure Reagan's place in history.' "It could be a very curious political alignment,' another ranking congressional staffer muses.

All of which means that treaty critics, like Armed Services Chairman Sam Nunn, will end up standing somewhere in the middle. Nunn is still vexed at the Administration's efforts to make an end-run around the ABM treaty, and is expected to use delaying tactics to prod the Administration into taking the Senate's treaty-making role more seriously. To gum up the works, Nunn will probably ask State and Defense to collect, collate, and transfer to the Hill the mountains of paper from three sets of Geneva talks, but other Democrats will not want to hold hostage the agreement they have long called for.

DOES IT MATTER whether the Senate ratifies a treaty before Reagan bows out? Probably not. Reagan would still get the credit (blame?) for the deal. As for the 1988 presidential race, a superpower agreement would make arms control a non-issue, with the public at least temporarily content with such perceived progress toward peace. Other issues would rise in importance.

But an arms treaty would sharpen the debate on SDI. Democrats would be likely to question the necessity of spending billions on a space shield when diplomacy has proved so visibly "fruitful.' The GOP thus would find it more problematic to argue for SDI, but at the same time would be better able to justify past Republican defense policy. Reagan's strengthening of the military allowed an acceptable U.S./ Soviet arms treaty to be negotiated, Republicans would argue, without compromising U.S. security--while incidentally, they hope, enhancing Ronald Reagan's place in history. Inshallah, as the Arabs would say.