The hip-shooters in Congress who would renege on the hostage agreement seem not to have quite grasped the significance of what the Soviets were up to in the final frenzied days of maneuvering for the hostages' release -- and why.

The Soviets were doing their bombastic best to sabatage the deal.

Why? Because, according to U.S. analysts, the Soviets didn't like what the hostages' impending release said to them about the internal politics of Iran. What it signified was that "moderate" influence is on the rise in the faction-ridden power structure that passes for an Iranian government.With the hostage issue out of the way, the fear in Moscow was that sooner or later Iran would begin edging back toward "normalization" of its historic relations with the West -- sooner, with Europe, but later with the United States.

That's not just a guess about Soviet thinking by the U.S. government's analysts. It is based on intelligence reports described by one of the leading figures of the departed Carter administration as highly reliable "intercepts."

It was these reports that prompted the Carter administration to respond with an unusually blunt protest when the Soviets, just a few days before the hostage settlement, jumped in with an official pronouncement accusing the United States of planning a military attack on Iran. The fear was that this could torpedo the talks, then in a particularly precarious phase, by inflaming Iranian fanatics and undermining the "moderates" pushing for a settlement.

Now if that's the Soviet game -- to stir extremism on the Iranian right in the interest of squeezing out more moderate forces and promoting Iran's communist-oriented far left -- it becomes almost reason enough for the United States not to renounce the hostage settlement. To do so would be to cut the ground out from under precisely those elements the United States ought to be trying to encourage an reinforce.

To its considerable credit, the newborn Reagan administration, still only loosely in place, seems to have met this first test with admirable restraint and long-headedness. So have Senate Majority Leader Howard Baker and the new chairman of the Foreign Relations Committee, Sen. Charles Percy. The new Republican leadership downtown and on the Hill was wise to move swiftly to try to damp down the initial impulses of many in Congress to "punish" Iran.

The instinct for revenge is understandable. It is only natural to find gratification in hollering about "blackmail" and "extortion." There was a little of both in the hostage settlement. The reports of torture and abuse, now spilling out, are grounds enough for revulsion and a powerful emotional response.

It is convenient, too, to see the militants who kidnapped the hostages and occupied the embassy as one and the same with the Iranian politicians who helped engineer the hostages' release. "They are all, after all, the creatures of the Ayatollah Khomeini," said The Wall Street Journal in an editorial entitled "Renounce the Deal."

But, of course, they aren't. It would take a half-dozen of these columns to delineate all the diverse elements in Iran's turbulent, unfinished revolution. And it would take the gifts of a soothsayer to predict how Iranian politics will now evolve.

On some points, however, almost all the experts agree. The hold on power of the octogenarian Ayatollah Khomeini is shaky, and unlikely to last much longer. Even the lifting of sanctions won't solve or even greatly ease Iran's economic crisis. The war with Iraq sputters on, its outcome unpredictable.

But to the extent that the ending of the hostage crisis helps clear the way for a solution to all of these problems, it also strengthens the hand of those Iranian political figures who favored it.

This would not be reason enough to honor the hostage settlement if it was, in fact, dishonorable. But this was not some private deal cut by the United States with kidnappers. Whatever pressures the United States was under to enter into it, it has the weight of an international agreement. Algeria and other countries were deeply involved.

So if he hostage seizure was immoral, as well as illegal, the morality of the question of honoring the settlement cuts two ways. Surely some value attaches to the sanctity of the word of the United States, given in concert with intermediaries acting in good faith.

The common sense of the matter moreover, cuts only one way. Many of the same people who would surely count themselves among the shah's stoutest supporters. Which is to say that at one point, anyway, they recognized the crucial geography of Iran.

The United States can find ways other than reneging on the hostage deal to signal what its policy would be in future cases of hostage-taking. There would be little to be gained and much to lose by repudiating those who show the most advance America's long-term interests. Iran's geography is no less crucial now than it was in the time of the shah.