Gary Hart may not have high enough morals to be president, but he would probably make a very good anchorman on television. Ted Koppel, meanwhile, was looking awfully presidential last night as he gently grilled Hart on a special edition of "ABC News Nightline" that marked Hart's first major interview since stepping down as a presidential candidate in May.

Hart retreated under a cloud, a real whopper of a cloud -- allegations of an extramarital dalliance with actress Donna Rice -- and last night Koppel asked him point blank, "Did you have an affair with Ms. Rice?" Hart said he would not answer "any specific questions about any individual." But if he should be asked whether, through all 29 years of his marriage, he was totally faithful to his wife, "I regret to say, the answer is no." He was thus belatedly answering a question from another reporter that he refused to answer last May: "Did you commit adultery?"

When Hart answered that question, in effect, "yes" last night, he also pleaded that the press "never ask another candidate that question" on the grounds that it is irrelevant. But as Koppel pointed out to Hart, the question was relevant, at least in Hart's case, because the answer could indicate "bad judgment ... something we do not want in our president."

Hart responded that he had already made "a confession that would probably make Nathaniel Hawthorne wince" and indicated he would go no further. He'd gone far enough, surely, to titillate "Nightline" viewers, who were promised by Koppel at the start that he would ask Hart "two questions in particular" before the one-hour, expanded broadcast was over.

Koppel, a showman as well as a journalist, withheld the first question, about Rice, until almost the midpoint of the program. The second question -- was Hart jumping back into the presidential race? -- was saved for about 10 minutes later. Hart said he was not, but seemed to hold out the possibility that he might at some future date.

Insisting he'd been guilty of "not crime, but sin," and noting the Bible declares "we're all sinners," Hart said, "One of the greatest sins is to waste God-given talents. I've been given some talents ..." No snickering, please! Hart explained later that the talents he meant included "an ability to communicate with people on an intellectual and a nonintellectual level."

Hart was communicating successfully on the Koppel show. There was a certain hooey content apparent in his semicircuitous rationales (even Koppel suggested there was "snorting and thigh slapping" going on over some of Hart's explanations), but he came across as genuine, as someone who believed what he was saying. This is what suggests he might make a good TV news anchor. His chiseled features do photograph well. He exudes credibility, which is no mean feat after the mess in which he's been embroiled.

"I'm not a perfect man, Mr. Koppel," said Hart. "I'm human. I commit sins." Koppel restrained himself from demanding a detailed enumeration.

Koppel and Hart sat side by side, not the usual "Nightline" format. Usually Koppel sits at his pulpit and questions newsmakers who appear on a big screen in front of him, even if the newsmakers are in Washington and sitting in the same ABC News building on DeSales Street from which "Nightline" originates.

Why did Hart get special treatment? Because he asked for it, Koppel said yesterday from his office before the broadcast, and because of the "very personal" nature of the questions. Koppel said similar special treatment was given former presidential adviser Robert McFarlane and Henry Kissinger on previous "Nightline" programs.

It was Richard Harris, one of the "Nightline" producers, who first approached Hart about appearing on the show last spring, when the scandal broke, Koppel said. He and Hart have had several telephone conversations since. At first Hart wanted it stipulated that if he appeared on "Nightline," no questions about sex and scandal would be asked, and Koppel said he told Hart, "Look, I don't think you're going to find a reporter in the country who's going to sit down with you under those conditions."

The trademark of "ABC News" was flashed over Hart's picture several times when he spoke last night so that other news organizations using the footage later would be sure to include the credit. In fact, ABC News has been the most aggressive and comprehensive on this deliciously tawdry tale. In June, Barbara Walters landed the first big TV interview with Rice for ABC's "20/20." Walters asked Rice, "Did you share a room, did you sleep with Gary Hart?"

And Rice, apparently with no irony intended, responded that she would not answer because it was "a question of dignity."

With commercial time subtracted, last night's "Nightline" interview lasted about 45 minutes. It was, as might have been expected, riveting fare all the way, and Koppel and Hart were both at their best. Hart looked squarely into the camera during the shot of him that opened the show. It was a "trust me" sort of gaze more than a "forgive me" sort of gaze, though at the very end of the show he dramatically apologized to his son and daughter, near tears when he expressed "how sorry I am for letting them down." Nathaniel Hawthorne would not have winced. Neither would Richard Nixon, probably. Nor Ollie North. Political theater this juicy gives politics a good name -- so to speak.