FOR FOUR MORNINGS last week, Richard M. Nixon was back in the news, being interviewed by CBS correspondent Diane Sawyer. This third segment, broadcast Thursday on the CBS Morning News, dealt with the Watergate break-in of June 17, 1972:

Q: What does this anniversary mean to you? Anything?

A: Well, only that it happened a long time ago, and it reminds me, of course, of the fact that I went through it 10 years ago, and relived it several times since. I, as you may recall, taped 26 hours of television for David Frost about Watergate and related issues; I spent three and a half years writing my memoirs, and several hundred thousand words on Watergate in that. And having done that, lived through it three times. As far as I'm concerned, I've said everything I can on the subject; I have nothing to add, and I'm looking to the future rather than in the past.

Q: But 10 years later, when you sit and look back and think about it, it's got to be a different feeling, or at least when you say to yourself, you know, "Why did it happen?"

A: Well, I think that it's understandable that with the morbid fascination that Watergate has, particularly for people in the media, who feel that they played a great part, as they did, in not only Watergate but the Vietnam War and everything else where they opposed me; that under the circumstances, they think that I, therefore, must be like they are, and that every year I've got to look back and wring my hands, and say, "Why did this happen? Why did this happen?" and so forth.

My attitude is somewhat different from that. I think -- well, one of my favorite expressions was, when we made some of the tough decisions that helped bring the war in Vietnam to an end, like going into Cambodia, which of course saved thousands of American lives by destroying the Communist supplies in that area; the bombing and mining of Haiphong, which incidentally was also just 10 years ago -- that's another anniversary that was happening, which of course set the stage for ending the war and getting back our POWs. And after it happened, there'd be demonstrations in the streets, and all that sort of thing, and people would come to the office wringing their hands and saying, "My God, couldn't we have done it a different way, or maybe we shouldn't have done it." And I always said this: "Remember Lot's wife. Never look back."

Now, I don't mind others looking back, and being critical: "Why was this done? Why was that done?" and all that sort of thing. If they think that's going to serve the interests of the country, let 'em do so. I don't think it is, but maybe it'll do their own Narcissus complexes some good, and if it does, that doesn't bother me a bit. But as far as my participating with them in it, no way. I'm looking to the future. They can look back.

Q: But a lot of people say -- and these are common people, ordinary people, people in the street -- that you never just said, "I covered up, and I'm sorry."

A: Well, that is, of course, not true. As a matter of fact, if you go back and look at the Frost broadcast, and if you read my memoirs, I covered all that in great, great detail. And I've said it all, and I'm not going to say anything more in the future.

Q: Do you think about it when you're just sitting alone, when you're not working?

A: Never. No. If I were thinking about it, I wouldn't be able to do what I think is some of the constructive work I've been doing on my new book, and also I'm preparing for the travels I'm going to be doing. You see, I understand the obsession with this subject. It's understandable. But people who are obsessed with it don't understand me. I went through it, I know what went wrong, I know that I have a responsibility, I'm not trying to excuse myself. But I'm not going to spend my time just looking back and wringing my hands about something I can't do anything about.

Q: You don't even sit sometimes and think to yourself, once again, as everyone thinks you must, "Why didn't I burn those tapes?"

A: I've covered that also, of course, in my memoirs and I must say that I must get, oh, a half a dozen letters a week even now: "Why didn't you burn the tapes?" And the answer is, of course, I should. It should have been done. But the main part is, they should never have been started.

Q: You did say to David Frost that you had made horrendous mistakes, one not worthy of a president, ones that did not meet the standards of excellence that you had dreamed of as a young boy. What was the worst one, the thing that you're most sorry about?

A: Oh, I've covered this in great detail, and I'm not going to go into it any further.

Q: There's no one thing that you had in mind when you were saying that?

A: Well, I've covered it already, but perhaps, on reflection, the thing that was the greatest mistake was in failing to concentrate on it the moment that I got the word on it.

Q: What's it like to be Richard Nixon, and to go out and walk into a room? What do you sense when you walk into a room? Do you ever think, "These people are looking at me because I resigned," or --

A: No, I never look back. I never look back. And people are very friendly. You have to realize that people who reach the highest levels in public life don't become obsessed with themselves, and thinking, "Oh, my God, what are people going to be thinking of me?" and asking. If they do, they're never going to be great leaders.

Q: You also said to David Frost, "I let down my friends, I let down the country, I let down an opportunity I had for projects that would have built a lasting peace; and I let the American people down, and I have to carry that burden with me for the rest of my life." Does the burden get heavier or lighter?

A: Now that says it all, right there, and as far as I'm concerned, having said it then, I'm not going to say it again now.

Q: Could I get some phrases again (characterizing former associates)? John Mitchell.

A: Well, I think we've covered enough, now, so I think we'll --

Q: How about John Dean?

A: No comment.

Q: You won't even say whether the burden, year by year, gets heavier or lighter?

A: No, I've already pointed out that I'm not looking back.