The ABC News program "Nightline" is so praiseworthy in design and so exemplary in execution that it's almost unthinkable to grump about it. But recently the program tottered into perilous waters when it asked the viewing public to vote, in effect, on how it wanted a news story covered.

On the July 13 edition of the program, host Ted Koppel offered viewers the chance to phone a 900 number flashed on the screen, and, for a charge from the phone company of 50 cents per call, vote on whether the so-called "Debategate" story involving pilfered papers from the Jimmy Carter campaign should receive "major attention" or "minor attention" from the news media.

Not very surprisingly, the results were overwhelmingly in favor of minor attention and, implicitly, against further pursuit of the story. As reported on the ABC News program "Viewpoint" the following night, of 250,000 people whose calls were registered, 66 percent voted for less coverage of "Debategate" and 34 percent voted for more.

Even as he was reporting the tallies on the air, Koppel took note that conservative Republicans would probably vote strongly in favor of less "Debategate" coverage and that as a group, they had "more 50 centses" at their disposal with which to register opinion. In other words, he was admitting the poll was tacitly unfair, inadmissible evidence. But even if it weren't, one has to wonder what the results were supposed to prove, and what is to be done with them.

George Watson, an ABC News vice president and the executive in charge of "Nightline" and "Viewpoint," defends the poll--"You ask if we have any second thoughts? No"--says the telephone polls ABC takes are corroborated by more "scientific" public opinion polls taken separately, and vigorously denies that the results of a poll like the one on "Debategate" have had any effect on ABC's own coverage of the story. "It's insulting to us to imply that we make news coverage decisions on the basis of public opinion," Watson says from New York. "If we did that, the famous credibility on which we depend would be with us for a very short time."

And yet ABC News was asking its viewers how much coverage they thought a certain story should receive. It well may be that "Debategate" (admittedly, a shabby nickname for the story) has been overplayed, but it's a story that isn't over yet, so how is anyone to know? It may turn out to have been underplayed. The public has a right to an opinion, even one borne essentially of ignorance, but for ABC to incorporate a shallow sampling of that opinion in its reportage is to crossbreed "Nightline" with "Family Feud" ("We surveyed 100 peo- ple . . .").

If broadcast journalists start doing this with every news story, the majority of people would vote for good news all the time. At the very least, they would vote for more sex-tape stories and fewer sour notes on unemployment or political scandal.

Watson, asked if he agrees with the majority who voted that "Debategate" has received too much attention, says, "No." Then he is asked if "Nightline" and "Viewpoint" aren't playing into the hands of the new antimedia establishment developing in the country. "I certainly don't think so," Watson says. "It's difficult to know the consequences of reporting something like this, how it affects people. But I do have my theories and suspicions. I think that by raising the issue on 'Viewpoint' and allowing people on both sides of the coverage to have their say, maybe we can counter the suspicion that the media is arrogant and unresponsive to people who say we're full of whatever. I agree there is an antimedia feeling in this country that is probably growing; what we do is provide a forum for critics who feel there's no way to talk back to the bloody tube."

And in so doing, Watson thinks, some of that antimedia feeling can be ameliorated.

Each week on CBS this summer, the happy news of the Charles Kuralt "On the Road" show has outrated by a wide margin the largely unhappy news of "Our Times with Bill Moyers," which immediately follows it. Although both are outstanding programs, even Kuralt will concede that what Moyers is doing matters more. But it is also upsetting, and deals with unpleasant, sometimes discouraging realities. If CBS bowed to the public's "vote" via the Nielsen ratings, it would dump the bitter pill of Moyers' show and renew the cheery cup of cocoa prepared by Kuralt.

Neither show is getting the size of audience it deserves. We are talking about top-flight TV journalism, the best, but the networks have done too good a job conditioning viewers to reject anything but air bubbles between 8 and 11 p.m. Television, it could well be argued, is turning us into a nation of softies, treating us like children for whom snacks and pastries are available virtually all the time.

It's a natural and human condition to prefer good news over bad. It's like preferring an ice cream sundae over spinach. But television constantly and slavishly panders to public whim, more than to an enlightened conception of public good, and it does enough stroking of its audience without putting the content of the news up to a national plebiscite--or even taking a tiny, creepy step in that direction. Thus, the poll taken by "Nightline" was a service to no one but the phone company. It made $125,000 on ABC's bad call.