In the late afternoon mountain cool of Santa Fe, John D. Ehrlichman, tanned and bearded and nearly as laid back as the old town itself, drove a dusty Ford Bronco over country roads to pick up his small stepson at the local Montessori school. He had spent the morning writing. Had it not been for visitor, he would have used up the afternoon prowling the local art galleries or sketching or trout fishing.

He has a new wife 24 years his junior -- young, bright, pretty and as chirpy-cheerful as a bluebird. He has a new novel which will probably be a bestseller. In New Mexico he has friends and respect and a nice parole officer. That evening, he would dine at Santa Fe's best restaurant, coddled and fussed over by the owner who is always flattered by his patronage. If living well is the best revenge, Ehrlichman has that too.

The last time most of us saw him, Ehrlichman was gripped in the unwelcome embrace of a congressional witness chair.Of all Richard Nixon's cohorts summoned before the Senate Watergate Committee and into the range of the television cameras, he was surely the least attractive -- cocky, pugnacious, tough and nasty. And he often seemed untruthful. That was nearly six years ago. Now when I report that I am writing about Ehrlichman, people ask, "Is he the one who got religion? No, that was Charies Colson.

In the Nixon days, outsiders even confused Ehrlichman with H.R. (Bob) Haldeman, guardian of the door to the Oval Office, and during their years as two of the dominant figures in the Nixon White House, even habitues of the place took to referring to them as Herdleman. Actually, they resembled one another only in the way they resembled every careerist who upon being promoted into power overnight turned mean and bullying. But there were important differences. Ehrlichman was the one with the sense of humor and a feeling for the language, a born wordsmith who crafted cruel poetry out of an embattled FBI chief's troubles by proposing that he be left "twisting slowly, slowly in the wind."

After the hearing, Ehrlichman was twice tried on two different conspiracy charges involving the White House scandals and convicted both times. He was barred from the practice of law. He came to Santa Fe and wrote his first novel, The Company, a slick pop view of corruption in high places in Washington. It was a success. He went to prison for 18 months, beginning his term before an appeal was decided. At Safford, Ariz., a minimum security facility, he finished his second novel. He was released just a year ago.

Now he sits in the sandy yard behind the pink wall of his pink adobe house, looking down at the pink adobe town below and the brown mountains beyond that, acknowledging that the prison experience -- indeed, all his experiences since he was compelled to resign as Nixon's chief domestic counselor on April 30, 1973 -- have altered him in some ways, but not as dramatically as one might suppose.

He says the Ehrlichman we saw before the Ervin committee was not the prototypical everyday Ehrlichman. He saw himself besieged, in a hostile environment, in an adversary position, responding to combat as he would have responded trying a case in a courtroom in the old days when he was a Seattle real-estate lawyer. It was before he had become disillusioned with Nixon, and he still thought of himself as the president's advocate.

Besides, he was scared. Although it could not have been detected in his public performances, he says now that the entire period was the worst time of his life, even worse than pulling himself together to face jail. He had begun that year in a new, more visible role than he had had the previous term, and for a few months he could be found basking in the warm glow of media atention -- long, friendly pieces from the likes of Business Week and appearances on "meet the Press."

By April he was "making a free fall into the unknown. What I knew about grand juries and criminal law and all that you could put in your eye. I had no idea where I was heading. And when I first sensed the dimensions of the problem, I had a very very bad time."

Three years later he went on his book tour and found people gazing at him with astonishment. "My you've changed," they would tell him. "You're not the person I expected to meet."

"My answer to that is I never was the person everybody saw in the Watergate hearings. But I had realized that I was never going to catch up with my image. It was set in concrete. It bothered me enormously for a while, what people thought of me. But I made myself stop caring because I knew I couldn't do a thing about it, and I knew it was going to tear me up if I tried."

Ehrlichman had come to Santa Fe after his trials with no notion of permanence. His marriage was over. He thought of this amiable antique town, awash in tourists and Indian jewelry, as a place to make a "disconnection," a temporary haven where no one would notice or care if he stopped shaving and gave up three-piece suits. He had a book to write and a borrowed house in which to write it. Moreover, he had a plan to avoid confinement through alternative service by volunteering to work with Indians in the state.

When that fell through, Ehrlichman went to jail beginning his concurrent sentences of 30 months to 5 years about 8 months before he had to. He went because he recognized the odds against a successful appeal and because he could no longer cope with his anxieties about imprisonment.

He doesn't remember his dreams, but he would wake up each morning full of unfocused fears. Would this be the week the sky would cave in on him? "The days simply had no quality, and I came to realize this was not freedom. Mentally, it was worse than being warehoused for a while."

On Oct. 28, 1976, he presented himself at the Swift Trail federal prison in Arizona, a fenceless establishment with a broom and glove factory, two tennis courts and a population mostly of Mexicans jailed for illegally entering the country.

It was not nearly as bad as Ehrlichman's fantasies, and he looks back on it with amused contempt. "There were no physical beatings or things of that kind. There was no calculated harassment beyond the bureaucratic nonsense that you get in the army. It was as close to being in the army as any experience I've ever had. They dress you in army uniforms; you're supervised by a bounch of incompetents who used to be in the army and who are afraid for their jobs. The places is run by fear, just like the army. I think I slept on the same cot I had in 1943."

Safford authorities gave him a plum job -- the lobster shift at the powerhouse. Every hour from 3 a.m. to 7 a.m., he had to check gauges. In between he could sit undisturbed in the quiet of the night and work on his book.

The food at Safford wasn't bad, and he made friendships which outlasted his stay.

Although Safford was far less inimical than he had imagined, it still required considerable intellectual and emotional adjustment. Time is prison's unyielding oppressor -- time lost, time counted. Ehrlichman finally decided that for his psychic survival, he would have to stop marking off the days and, instead, use each one as if it were a special gift.

Suppoce he were terminally ill and knew precisely how long he had to live? "If you had 131 days, you'd savor every sunset, you'd greet every dawn as early as you could. You'd fill every day with as much sensual pleasure and intellectual pleasure as you could. And that's what I did. I finally turned it around."

The outside world helped. He got an immense amount of mail -- letters and reading matter from friends and strangers. Henry Kissinger bought him a subscription to the Wall Street Journal because he thought it important that Ehrlichman keep up. Rep. Paul N. McCloskey Jr. (R-Calif.) wrote often, visited several times and, one November, turned up with a complete Thanksgiving dinner for him.

Theirs had been a long, warm association begun during college years at UCLA and famously ruptured when McCloskey took a hard stand against the Victnam adventure. "It was my fault," Ehrlichman says. "See, he would call me up and say, 'I wanna ride to work in the morning.' So I'd stop by and pick him up and then he'd work on me all the way in. And it just got too rough. So I finally had to say, 'Look, I can't be both thing. I can't be your friend and work at the White House, and so we're just going to have to have an interlocutory separation until I don't work here any more."

When his trials were over and he was preparing to leave for New Mexico, Ehrlichman wrote to McCloskey and mended the friendship. It was McCloskey who prodded Ehrlichman into using his last months in jail to do research on the prison's wetback population; a Chicano cellmate helped him conduct interviews for an article he is now writing. And when the house Ehrlichman had rented in Santa Fe came up for sale, it was McCloskey who managed the purchase for him. Prisoners can't do business.

The $89,000 place McCloskey helped Ehrlichman buy is really a walled compound with two houses. The smaller building is used by one or more of his five children when they visit, the slightly larger one by his wife, the former Christy McLaurine, and her son David, 4. The oldest room in their house was built 165 years ago, and all the rooms have "vigas," the crude ceiling timbers which appears to be the main selling point of homes listed in the local real-estate ads.

As the day cooled, we moved into the living room. It is sparsely furnished -- an old round oak table, a few local artifacts, a lot of plants and a pair of handsome wicker chairs which last year changed Ehrlichman's life. He had seen some in the movie "An Unmarried Woman," wanted them and had spent his urban excursions shopping for them. While in New York on business in the spring, he began canvassing showrooms specializing in wicker. The fifth one he tried not only had the chairs, it employed Christy McLaurine as an interior designer.

Ehrlichman bought the chairs and on the plane home that afternoon wrote her a note. Thus began the courtship. They married in Noember and appear to be living happily ever after.

The Ehrlichman home is on a hilltop, reached by a winding dirt road and populated mostly by families of Hispanic origin. It is hard to picture the Ehrlichman of old boasting with Brotherhood Week pride that he and the son of Marquis Childs, the columnist, are the only Anglos on the slope.

Ehrlichman turned 54 in March. He is a large, soft man with a midsection as ample as ever, and food is clearly important in his life. At lunch downtown that day, he passed up dessert only after what was good-humoredly described as a "titanic struggle." Although he has never consumed hard liquor, he is not the total abstainer he was assumed to be in his White House days: dinner was accompanied by a carefully chosen French white wine.

There is gray in his beard, and the spray of lines radiating out of the corners of his eyes gives him a benign avuncular look; only rarely is it dissolved by a familiar, joyless feral grin that is an automatic response to any hint of hostility. Mostly he is agreeable, gracious and entertainingly ancedotal. If he harbors any rancor over the past, it would appear to be channeled wholesomely into his fiction.

The new novel is called The Whole Truth. It could be subtitled Ehrlichman's Revenge. As The Company did, it again offers Ehrlichman's cynical view of a national government in which just about everybody is corrupt or corruptible. It features a besieged president whose chief transgression is not lying but getting caught at it.

The hero is a younger, romanticized version of Ehrlichman -- an idealistic, ferociously ambitious West Coast lawyer who, seduced by the power and glamor of White House life, undertakes an illegal act at the bidding of his president and then is expected to take the fall for it. The story has an attorney general's wife who could be a double for the pushy, pathetic Martha Mitchell, a duplicitous occupant of the Oval Office who is Nixon's spiritual heir, and televised hearings pursued by a malevolent Southern politician broadly drawn along lines that conjure up former Sen. Sam Ervin.

The book says what Ehrlichman has always said in dealing with the Watergate episode -- all our modern presidents have been equally unattractive morally. (It does not, however, stress that only one, through the creation of an in-house team of investigators that came to be known as the Plumbers, institutionalized the pursuit of leakers and political enemies.)

Sprawled in his wicker chair and cheerfully twirling his glasses, Ehrlichman volunteers, "My premise is that nice guys don't get to be president." Needless to say, the assessment includes the present holder of the title.

As for his own past, Ehrlichman still views the two events that sent him to jail as "mistakes" but not criminal mistakes. He was convicted of obstruction of justice in the coverup of the Watergate burglary and of authorizing the burglary of the office of Daniel Ellsberg's psychiatrist and of lying about both events. Now he chooses his words with care, saying, "I still would have to take the position that I did not knowingly participate in either of the conspiracies I was charged with."

History, he thinks, will perceive that entire period differently, although he has no expectation that it will absolve him or support his still-vehement claim that, with the theft of the Pentagon Papers, genuine national security reasons existed for investigating Ellsberg by all possible means including the effort to examine his doctor's files.

In any event, Ehrlichman seems to hold no visible grudges for some old enemies. Last spring, shortly after his release from prison, French television paid his way to Paris by Concorde so he could appear on a panel program about the Nixon presidency. One of the other panelists was Bob Woodward, who, with Carl Bernstein, had no small part in exposing the Watergate scandals.

After the taping, Ehrlichman lunched with Woodward. They talked casually about the past and more seriously about Woodward's new project, a book on the Supreme Court, and then went off together to see a Cezanne exhibition. "We parted as good friends," says Ehrlichman.

Woodward also found the encounter impressively pleasant and remembers his surprise at how relaxed Ehrlichman was and how completely he seemed to have put the past behind him.

Ehrlichman's feelings for Nixon are less amicable. The loyalist of the Ervin committee hearings was transformed into a dissident the summer of 1975. In preparation for his trials, he spent weeks listening to the tapes the White House had been compelled to surrender to the office of the Special Watergate Prosecutor. It was a revelation, he says, to hear Nixon telling other people things "diametrically opposed" to what Ehrlichman had been told. "He was working both sides of the street."

His shock is a little surprising considering how well he understood Nixon and how well he learned to manipulate him in matters involving affairs of state. When it was mentioned that Ehrlichman once had been described as the conscience of the White House, he stroked his bald head reflectively and said it was an identification he had been careful to avoid.

"With Richard Nixon you could not effectively function if you were perceived as the conscience of the White House. You had to meet him where he was. You had to talk to him in functional terms. If you saw something you didn't approve of, you had to figure out a way to present it to him, a way that would appeal to his sense of political reality. If you wanted to get results, you didn't go in there and say, 'Sir, 20 bishops have endorsed this, and it is the right thing to do.'"

That may sound like a strain only to persons of limited imagination. Ehrlichman used to think of the relationship in terms of big business, of a Xerox or IBM salesman preparing the pitch and asking himself: "What will motivate this guy to buy my product?" As Ehrlichman says he saw it, "The White House is a big marketplace of ideas, and you've only got one buyer."

Ehrlichman had come to Nixon through Haldeman, another old UCLA classmate. Recruited to help in the early unsuccessful campaigns, he had been asked back for the winning one in 1968 and had then moved into the White House. He did not especially like Nixon, but he respected his brains and his ability, and he was grateful for Nixon's confidence in him. "I had a pretty free hand as long as it didn't slop over into the political area and cost him anything."

He detected some flaws, but where someone else might have thought they represented character defects, Ehrlichman saw a man who feared confrontation and was terrified of hostility. He knew there were sharp differences between the public and the private personae, but he had no idea how many Nixons there were until he heard the tapes.

"Talk about needing controlled environments," Ehrlichman exclaims.Tone of voice, choice of words, syntax -- every element of speech varied, depending on whether he was talking to Chuck Colson or Henry Kissinger or Bryce Harlow. Profanity was used selectively. Meetings with Pat Moynihan, for example, had no expletives to be deleted. "He was never crass with Moynihan because that's the way he understood Moynihan -- as a Harvard professor of lofty ideas. You know, all that."

Few of Ehrlichman's White House associations have withstood the strains of the Watergate period. He has maintained a casual relationship with Haldeman, whose friendship seems to have survived the derisive view Ehrlichman gave his Watergate book in Time magazine. They do not correspond with any regularity but on learning they were to be in New York at the same time, they arranged to dine together after first getting permission from their respective parole officers. In general, alumni of penal institutions are forbidden to consort with one another. For the remaining year and a half of his parole, Ehrlichman must have formal approval before he leaves the state to undertake anything like the multi-city tour he will be making on behalf of his novel.

The last time Ehrlichman talked to Nixon was at Camp David when the President tearfully told him he must resign. Nixon did send him an autographed copy of his memoir, and Ehrlichman will probably reciprocate in a few years. In the bedroom where he does his writing, 20 cartons of notes from the White House years are stacked against the wall, and Ehrlichman is about to start transforming them into his story of Watergate.

Writing is easy for him, and he blocks rarely. "Once in a while I'll come to an absolutely blank wall. Then I pretty much gotta lay it down and go do something else. But it doesn't take very long. That's one of the really pleasant things about writing fiction, the way those doors open. Something like that happens in painting that I've experienced a couple of times. It's a high, it's a real kick to see that open up."

Along with book writing, he handles several other remunerative gigs. One morning a week, Ehrlichman composes and tapes five 60-second commentaries on current events for the Mutual Broadcasting System which sells his feature, "The View From Here," to 120 of its radio affiliates.

No more than five times a year he will lecture, reportedly for $3,000 an appearance, at a college or before a business group. Folks are friendly, he reports, but he expects a modest show of animosity and has no trouble dealing with it.

During the question period, someone in the audience invariably challenges him about profiting from notoriety. Fairly aflame with sincerity, Ehrlichma observes that tickets have been sold for $2.50, and he doesn't know whether he can provide $2.50 worth of useful information, but that is certainly his intention. If he succeeds, he offers no apology. If he doesn't, dissatisfied ticket-holders should demand their money back. On the other hand, anybody who would come expecting a freak show is not going to get value for the money. So far, nobody has ever asked for a refund. CAPTION: Picture 1, Christy McLaurine and John Ehrlichman were married last November and live in the pink Sante Fe home seen in the background. They met last spring in New York at a furniture showroom where she worked as an interior designer.; Picture 2, Ehrlichman has boxes and boxes of documents from his White House days and plans to convert them into his own version of the Watergate story in the next few years. Other than writing he lectures no more than five times a year for a reported $3,000 an appearance. Next Saturday he is acheduled to speak before the White House Fellows Association.; Picture 3, No Caption