Richard M. Nixon last night held to the main lines of his Watergate defense in much-touted television interview which shed little new light on the scandal that propelled him out of the presidency.

The 90-minute interview produced an emotional acknowledge from Nixon that "I let down my friends, I let down the county. I let down our system of government . . ."

But on the whole the President stuck to positions that had been carefully laid out during the period of intense legal deliberation between the June 17, 1972. Watergate burglary and Nixon's Aug. 9 1974, resignation.

Under prodding by interviewer David Frost, the former President pointedly denied committing any illegal act, but readily acknowledged the impropriety of his Watergate conduct.

"While technically I did not commit a crime, and impeachable offense . . . there are legalisms" he said. "As far as the handling of this matter is concerned, it was so botched-up.

"I made so many bad judgements. The worst ones, mistakes of the heart, rather than the head."

Frost presented Nixon with the record of his own words in the Oval Office. Nixon acknowledge that he went "right to the edge of the law . . . a reasonable person could call that a cover-up. I didn't think of it as a cover-up.

Nixon acknowledge he "said things that were not true" and considered courses of action he should not have even contemplated.

But he went no futher than he did in his resignation speech 2 1/2 years ago in expression of regrets and acceptance of responsibility for the final outcome of Watergate.

"If they want me to get down and grovel on the floor, or, Never. Ah, because I don't believe I should."

The interview leaves many of the Watergate questions unresolved.

On last night's interview show Frost did not ask Nixon who erased the famous 18 1/2 minutes of a tape of a Nixon meeting with his White House chief of [WORD ILLEGIBLE] H.R. Halderman, three days after the Watergate arrests.

Frost did ask Nixon what happened during that meeting. Nixon said, "Halderman's notes, ah, are the only recollection I have of what he told me."

Those notes show that Nixon ordered a public relations offensive on Watergate and nothing more.

Nixon also made no judgement on the guilt or innocence of his former top aides who have been convicted in the Watergate cover-up.

He did have words of praise for Halderman, calling him "not a German Nazi storm trooper, but just a decent respected crew-cut guy. That's the way Halderman was Splendid man."

Nixon also gave up no ground on his longtime claim that he first learned the details of the Watergate criminal cover-up during the famous March 21, 1973, meeting he had with his counsel John W. Dean III.

As the tape of that meeting has previously revealed. Nixon did [WORD ILLEGIBLE] paying blackmail demands by Watergate conspirator E. Howald Hunt. Last night he maintained the considered authorizing the payments to protect national security and possible [WORD ILLEGIBLE] cause the administration.

"I considered it for reasons that I thought were very good ones. Ah, I would not consider it, for, ah, the other reasons, which would have been in my views, bad ones," he said last night.

Frost also confronted Nixon with a tape transcript not made public before the interview were conducted.

[PARAGRAPH ILLEGIBLE]

After Frost read the porton to Nixon, the former President said that he was worried that the seven, some of whom had been involved in Central Intelligence Agency work, might embarrass the administration by exposing covert activities.

Nixon last night said that as of that date he was not aware that anyone else was involved criminally.

"I didn't know of anyboday at that point, nobody on the White House staff; not John Mitchell; ah, anybody else, ah, that I believed, ah, was involved . . .ah, criminally."

This appears to contradict the Feb. 13, 1973, transcript, which shows that Nixon was aware of Mitchell's involvement.

At that meeting, Nixon and Colson discussed who might step forward and take responsibility for Watergate.

Nixon: Well, who the hell do you think did this? Mitchell? He can't do it, he'll prejure himself so he won't admit it. Now that the problem, Magruder?

[Jeb Stuart Magruder was Mitchell's deputy at the Nixon re-election committee.]

Colson: Ah, I - I know Margruder does.

Nixon: Well then he's perjured himself, hasn't be?

Colson: Probably.

Later in the conversation Nixon said, "Mitchell seems to have stone-walled it up to this point."

Frost last night did not ask Nixon about that portion of the transcript.

Reitering a line of defense made before "resigning, Nixon said last night." I did not have a corrupt motive . . . My motive was pure political containment."

Interviewer Frost, on the other hand, voiced his own opinion that the Watergate record showed Nixon was a cover-up conspirator.

Nixon said that the interview would give viewers an opportunity to "make up their own minds." At one point he called Frost the "attorney for the prosecution," adding, "Let me make the case as it should be made . . . defense."

At one point, Nixon actually suggests that he acted as a defense attorney for his aides. This, he explained to Frost, made such advice as "Just be damned sure you, say. 'I don't remember, I can't recall,'" was "proper advice for one who, as I was at that time, beginning to put myself in the position of a attorney for the defense . . ."

Much of the interview centered on Frost bombarding Nixon with incriminating quotes from the tapes, and at times Nixon quoting back exculpatory phrases.

Nixon said that while in office during the Watergate period he was confronted with partisanship on the part of the Senate Watergate committee staff, the Watergate Special prosecutor's staff, the staff of the House Judiciary Committee, which conducted the impeachment inquiry, and by the news media.

No conspiracy, no coup, brought about his resignation, Nixon said. "I brought myself down. I gave 'em a sword. And, they stuck it in, and they twisted it with relish. And, I guess if I'd been in their position. I'd a done the same thing."