Richard Helms, widely accused of failing to keep in touch with the shah's opposition while he served as our ambassador in Iran in 1973-76, now offers his reply. It's not good enough.

The general question of what contacts the United States ought to have with the opposition is, of course, crucial. Scores of Third World countries important to us in various degrees face turbulence in the 1980s. Yet many of them run restrictive political systems in which the United States may enjoy only limited access to people likely to come to power. This opens up a troubling prospect of flying more or less blind.

Helms, director of the Central Intelligence Agency before going to Tehran, offers his specific answer on Iran in a brilliantly conveived symposium, "Contacts With the Opposition," put out by Georgetown University's Institute for the Study of Diplomacy. With the United States being roundly criticized for neglecting to establish timely contacts with the religious elements that ousted the shah, Martin Herz asked a clutch of fellow retired diplomats to mine the theme.

Helms concedes that "lack of attention to activity in the mosques in the poorer sections of Tehran was a failure of embassy coverage . . . The lack of coverage in depth of church activities during the '70s may well have prevented an adequate understanding of religious forces at work when trouble started in 1978."

He denies -- to me, unpersuasively -- that there were any "deals" cut with the shah to inhibit American intelligence-gathering. Yet he concedes indirectly that the shah's police and intelligence agency, Savak, misinformed the embassy about the country's political stability. And he says that against the embassy's need for political intelligence, it had to "balance" such competing interests" as listening posts for Soviet missiles. In what opposition contacts it did maintain, the embassy took care not to be too encouraging or visible. "We did the best we could . . ."

"Certainly it would have been useful to have advance knowledge," Helms concludes. "But the participants in the uprising did not themselves have that foreknowledge. It is thus questionable whether more contacts with religious and bazaar elements would have provided it."

Helms' authentication of the American intelligence lapse in Iran is valuable. But he shows a strikingly unprofessional diffidence in the face of it. How can a career intelligence officer say it would have been "useful" to know what was going on but it is "questionable" whether more contacts with the opposition would have helped?

How could better contacts not have helped?Had we been aware earlier of the shah's fading popularity and of the growing popular resistance to his rule and of the possibility of his being toppled, then at least we would have had a timelier chance to ask the root policy question of whether we wanted to harden our support for the shah or to lean harder on him or to disengage or whatever.

This does not ensure that we would have made the right policy decision, if there was any decision that could have spared us our current ordeal. But what is the purpose of intelligence, including contacts with the opposition, if not to arm policy-makers with the best available materials of decision? Helms' dismissal of what greater profesionalism might have produced in Tehran turns the intelligence creed upside down.

The worst of its is that, to judge by other testimony in this symposium, our lapse in Iran may have been something of an exception. There is perphaps less truth than commonly supposed to the popular post-Iran impression that regime-blinded American diplomates have avoided opposition leaders and movements for years. The symposium makes clear that regimes regularly object to such contacts -- but the contacts go on. It left me feeling that quiet embassy insistence can crack the case in many places and discretion (including use of the CIA) can work in others.

But the last word surely belongs to the shah. It is relayed by Wiliam H. Sullivan, our last pre-ayatollah ambassador in Tehran. He otherwise is tightlipped about Iran, but he does recall the shah's reaction when Sullivan informed him, just before the roof caved in, that the United States had arranged, but then suddenly canceled, a meeting in Paris with Ayatollah Khomeini. In "stunned incredulity," the shah asked, "How can you expect to have any influence with these people if you won't meet with them?"