CBS and Time-Life Television have certainly succeeded in personalizing and even humanizing, Watergate with "Blind Ambition," the eight-hour TV version of history according to former Nixon counsel John W. Dean. By the same token, they also have succeeded in trivializing it. The most devastating political scandal in the history of the republic here becomes, much of the time, merely the set of rocks on which a marriage almost flounders.

Stanely R. Greenberg's screenplay was adapted from Dean's book "Blind Ambition" and from his wife Maureen's book, "Mo: A Woman's View of Watergate." The first two hours air tonight at 8 on Channel 9, to be followed tomorrow, Tuesday and Wednesday night by succeeding two-hour chapters at 9 p.m.

What "Blind Ambition" inadvertently proves is that Watergate was more appallingly entertaining in its original form. But this handsome, sophisticated production does offer insights into the workings of politics and the nature of the political beast that are rare for television and bound to fascinate and irritate millions of viewers.

"Blind Ambition" has a more convincing tone of urgency and more potentially explosive content than most TV films, yet it isn't quite as stirring or engrossing as one might have hoped. The basic dilemma is the inclusion of the material from Maureen Dean's book; the courtship, roommating and marriage of John and Mo is forever interrupting the riveting rantings and ravings in the Oval Office.

"I want to know everything about you," Mo tells John in Chapter one. "that's all very boring," John says. After eight hours, one is inclined to agree. In fact, one is inclined to take him at this word from the outset.

Part Three might have been called "Not Tonight, Mo," as we learn how the unfolding White House scandal affected the love life of the Deans - adversely, as anyone might surmise. Dean tells his wife he doesn't feel like a "Don Juan" any more and she pouts. Like "Ike," the recent and highly rated ABC miniseries, "Blind Ambition" perpetually bounces back and forth from historical events to peephole romance. It doesn't quite work, but then, perhaps viewers interested in the romance will cool their heels during the Watergate portions and those concerned with Watergate will bide their time during the repetitious bill and coo sessions.

John Dean himself has only seen the first two hours of the program, and he is not sure how he and Mo will handle the rest; he expects they'll stay home and match. "When I saw the first part, it was kind of like the first time i listened to the tapes," Dean said from his Los angeles home late last week. "I felt embarrassed at some of the things that i heard and i felt pretty good about other things. I have the impression that they have played it straight down the middle, just like the book was written."

Dean had no official role in the filming except to approve the scripts and correct certain "minor technical details," he said. "We were terribly distant from the project. We sort of forgot about it and now it's upon us and i must say, there is trepidation. We're sort of standing naked again. We've been out there once, and it's not terribly comfortable.

I think we're kind of braced for a lot of shots being taken at us again, and that's not a terribly comfortable posture, either. I suspect that's going to happen; you know, that people will just start firing away at the Deans again," he said.

Greenberg's screenplay isn't very rough on Dean. Oh, Mo calls him "you dummy" and an "idiot," and his lawyer calls him an "idiot," too, and he does some faintly idiotic things, but basically he comes across as a combination of Chicken Little and the Little Red Hen. He sees the skey is falling and he runs around trying to get others to help him pick up the pieces. They won't. Deanis portrayed as a martyr, and though the script has him blaming "stupid obedience and blind ambition" for Watergate, it is kinder to his own ambition than Dean was himself in his book.

Martin Sheen, who plays the character, always seems more reminiscent of James Dean than John Dean anyway. He never captures that peculiar Wind in the Willows quality Dean had on the witness stand. As wife Maureen, Theresa Russell has far more depth as a character, and even when hysterical in the later chapters, she behaves in a way that is consistent with the icy cool Maureen we watched on TV long before Watergate became fodder for prime-time follies.

The spellbinding performance, though, is Rip Torn's sterling trun as Richard M. Nixon, probably the Yummiest Richard, from an actor's point of view, since The Third. Torn doesn't do a nightclub impersonation, but he has got most, if not all, of Nixon's mannerisms down pat; he is as much sheer and macabre fun to watch as a monster movie.

This doesn't mean the portrait is cheap or malicious; it is just delicious, a pleasure to behold, a truly polished worked of art, and there isn't nearly enough of it in "Blind Ambition." You are always waiting for Torn's Nixon to return.

All the dialogue we hear from Nixon and associates in the Oval Office was taken from transcript of the White House tapes. This is fine as far as it goes, because it's still a kick to hear those discussions - even if CBX has seen fit to clumsily bleep expletives. But since the speech patterns change the dialogue stops overlapping the minute we leave the Oval Office and the official record, there is a stylistic chasm between these portions of the film and the others.

Most of the president's men are played satisfactorily. William Daniels is particularly sinister, in a klutzily clandestine way, as G. Gordon Liddy. When he tells Dean that he is willing to be shot on a street corner if it will serve the cause, Sheen replies "I really don't think that's going to be necessary" with a shaky astonishment that suggests an old Bob Newhart routine.

John Randolph makes John Mitchell a sympathetic figure-which isn't going to jell with everyone's view of recent history-while Lawrence Pressman all but snarls and shows his teeth as H.R. Haldeman and Graham Jarvis is clearly meant to suggest shifty menace as John Ehrlichman.

Veteran producer-director George Schaefer got from many of them moments that at least suggest a dreadful reality; he sustains a climate of escalating madness and desperation that is almost as thick ad the angst in a Bergman picture or the aura of depravity in something like "The Damned." Still, it is not a movie filled with high moral outrage - not until the last minute when Dean, after four months in a cushy sort of a jail, is asked by an offscreen voice, "Mr. Dean, Mr. Dean, could Watergate ever happen again?"

There is no answer - ONLY AN OMINOUS SILENCE. Perhaps executive producer David Susskind suggested that corny ending himself.

Whether viewing America is anxious to see a replay of the Watergate mess remains unpredictable. "Washington: Behind Closed Doors," a thinly plated roman a clef from a John Ehrlichman novel, didn't break any ratings records when ABC showed it in late 1978, and it is unlikely the miniseries, though marked by grit and energy, will ever be shown by the network again. That means they lost money on it. Losing money is a capital offense in network television.

And yet CBS has scheduled "Blind Ambition," after some delay, during a "sweep" month in which critical ratings are taken. If viewers are grabbed tonight, they are likely to remain with the show, sex and politics presumably still being unbeatable topics for luring the curious. And the novelty of hearing real names in a drama about corruption, and of seeing a recent U.S. president portrayed in anything but a favorable light, may make the shows a big draw.

Dean himself doesn't want to make any risky predictions about the fate of the program with the Nielsens. He was not thrilled by "Washington: Behind Closed Doors" either in book form - "not a particular form of fiction that I find entertaining"-or on TV. "I only saw one segment of it, and to me it was just incredibly distorted. Here were caricatures of the worst features of everybody that was involved."

(Dean also said he has read "the bulk of" Richard Nixon's book of memoirs but that "it's not exactly a page-turner.").

Of course, "Blind Ambition," which is not presented as fiction, raises old and pesky questions about the suitability of the docu-drama for dealing with such real-life events. Most of the Watergate figures are played by actors, but a newsreel shot of the real Gerald Ford pardoning Nixon was inserted. For some strange reason, former California senator John Tunney also shows up as himself, though his role in the Watergate investigations was anything but indispensable. Each chapter begins with the authenticating written and spoken announcement, "This film is John Dean's eyewitness account of Watergate. Scenes in the Oval Office are drawn from verbatim transcripts of White House tapes."

The Deans got $100,000 for the TV rights to their books-two for the price of one," Dean says. But of what possible benefit to the country is a TV version of "Blind Ambition?" Dean based his answer on how people he knew who'd seen the film had reacted.

"The reaction that pleased me most was not dissimilar to some reactions I got to the book," he said. "First of all, people said the story all fell in place for them in a way it hadn't before. They could grasp the sequence of events better. The second thing, I guess, is that a number of people said they could identify what happened there at the national level with what happened in their own lives. It's sort of, 'But for the grace of God, there go I,' which I think is a very honest thing for someone to say."

Dean sounded pleased with Martin Sheen's portrayal, but displeased by Russell's of his wife. "I think Theresa is an attractive girl, but I don't think she is Mo by any stretch of the imagination. I think Mo has mixed reactions about Theresa, too."

Dean has tried to keep up with books about Watergate, but sometimes they are off the bookstore shelves before he has a chance to buy them, he said. A journey of a thousand miles apparently begins with several dozen books.

"The curious thing," said Dean, "is that my story always formed the outer parameters of Watergate, and I don't even know what I didn't know. And no one else who has written about those years seems to be volunteering anything. So there may be gaps."

The television version of "Blind Ambition" may not close any of the gaps nor really amount to much of a sobering clarification, but for at least a sizable portion of its excessive running time, it does make a slightly fabulous circus of horrors. CAPTION: Picture 1, In "Blind Ambition," Martin Sheen and Theresa Russell as the Deans; Picture 2, Lawrence Pressman as Haldeman; Picture 3, Rip Torn as Nixion.