Walter F. Mondale's brother Clarence was quoted yesterday in a Style report as saying "the wisdom around here is that Walter Mondale can't win" the presidential election. The report did not include his statement that, while it would be a long, uphill battle, he thought it was winnable.

God hath blessed you with a good name. -- William Shakespeare, "Much Ado About Nothing"

It is misery to live in the fame of others. -- Juvenal, "Satires"

BROTHER AND SISTER, thy name is fame.

Laurance Rockefeller knows all about it, and Billy Carter too. As for Eunice Kennedy, she's always answering questions about what Ted thinks of this or Jack thought of that.

It's a curious life, a celebrity's sibling's. Many dine at the White House and never worry about tickets for the Academy Awards or film premieres or the Redskins. But after a while, they tire of being introduced as "the brother of the movie actress" or "you know, the senator's sister."

Who are they?

Those interviewed in the Washington area -- Clarence and Morton Mondale, George Jolson, Susan Spielberg, Ronald Hoffman and Mac Dunaway -- are very private people, seeming to ride the cusp of celebrity only with reluctance. Yoko Ono's sister, Setsuko Ono, a senior loan officer at the World Bank, refused to talk even on the telephone. But others did speak about themselves and, inevitably, about the brother or sister they grew up with who made them a sibling of fame. The Candidate's Big Brother

Brotherly love doesn't deter Prof. Clarence "Pete" Mondale from criticizing the Democratic presidential nominee's oratorical skills: "He gets so rigid when he speaks, he almost puts me to sleep.

"I think it's Minnesota style. I heard terrible speeches growing up."

A professor of American Studies at George Washington University since 1965 and a father of seven, Pete Mondale, 58, says he and his brother -- just a year and a half apart in age -- were once good friends. At their weddings they were each other's best man. "But then Fritz became attorney general [in Minnesota] very young," he recalls. "It was tough. I was the oldest and the pacesetter . . . the sibling rivalry . . . People started asking who the Mondale was . . . They kept saying the Mondale."

Sitting in his cubbyhole office on the second floor of a GWU row house, he wipes beads of sweat from his ruddy cheeks and forehead. The older, taller, heftier brother of Walter Mondale has just bicycled to work from his home in Mount Pleasant.

"We're not close," he says. "We're in two different worlds. But we are sympathetic." The one time he walked the few blocks from his office to the White House in the four years his brother was vice president was just after Jimmy Carter had lost the 1980 election. Otherwise their families get together on Easter, Thanksgiving and Christmas.

But practice has made the role of the "candidate's brother" easier. "Everyone is overshadowed by someone," he says. "You can't wring your hands and hide away in a closet."

He disagrees with "the stuffed-shirt character the press has settled on for Fritz," and adds, "It's not that he's boring." He just has a "deadpan sense of humor" and "Fritz thinks there is a certain way you should act in public."

He takes amusement in what he calls the "Washington gee-whiz factor": "People like to take my picture so they can say, 'Gee whiz, I stood next to the person who stood next to the person who might be president someday.' " This "glory by association" amuses him especially since he says, "I have absolutely no influence with my brother."

Does he think Mondale will win? Says the professor: "The wisdom around here is that he can't." 'Mammy's' Other Son

George Jolson wanted to go into show business, just like his older brother Al -- the vaudeville performer once billed as "The World's Greatest Entertainer." But Al Jolson -- still remembered down on one knee, arms outstretched and belting out "Mammy" -- told him it was the "toughest racket you could get into," and advised him to go back to school.

So George Jolson enrolled in George Washington University and became a pharmacist. But soon he got "sick and tired of it."

Sitting in the front-window office of James L. Dixon & Co., a real estate firm near Dupont Circle, he says, "Let me tell you how this came to be: Someone put an article in the paper about Al Jolson's brother selling his drug stores and James Dixon called me up. I told him I wasn't interested in buying real estate and knew nothing about it, but he said, 'It doesn't matter. Let's go to lunch.' "

Jolson worked with Dixon until he died earlier this year. "Yep, 27 years." Dixon's widow, real estate agent and seer Jeane Dixon, still shares the office.

When you ask his age, he responds quickly with "old enough." Later he says he is 15 years younger than Al, who died in 1950 and would have been 98 this year.

The Yoelson family (some of the family members changed to Jolson after Al took that name) lived in Southwest Washington on 4 1/2 Street (now an unnamed court near Southeastern University). George says many people still stop him on the street asking about his brother. He says he doesn't mind -- usually. But sometimes the "questions get so personal it's nauseating."

Yet being "Al's brother" had definite advantages.

"I went to three Joe Louis fights," he says, "and I suppose I could have gotten out of the war -- Al knew some three-star general at the Pentagon, or rather some three-star general knew Al." He grins. "That was World War II not the Revolutionary War, but I wanted to enlist."

He leans back in his black leather chair, and takes off his silver wire-rimmed glasses. Recalling the time Al came home before he had lunch with the president at the White House, he said, "No matter what he was doing he always came home." Another time, "Al came home and said, 'Let's go see Uncle George.' I told him we don't have an Uncle George. He meant he wanted to go to Mount Vernon. He said he hadn't been there since he was a kid."

When they got up to "Uncle George's" Jolson said they sat at a picnic table with a couple of Cokes and "in a few minutes there were about a thousand people around. That man was magnetic . . . and he was my brother." Growing Up Spielberg

Susan Spielberg's brother, director Steven Spielberg, has attracted millions to the box office -- and at least one date to her.

She remembers how, at the end of one evening, her date presented her with an 8-by-10 glossy of himself. "That might have had something to do with the fact that my brother makes movies."

One of the industry's most successful directors, Steven Spielberg, 36, has directed, among others, "Jaws," "E.T." "Close Encounters of the Third Kind" and "Gremlins." Susan Spielberg, 30, is happy to stay at home in Montgomery County and take care of her 2-year-old son Uri while her husband Jerry works at a Washington law firm. "Steve likes to say all of us Spielbergs create something," said Susan. "He creates movies. My sister Ann creates screen plays. Nancy creates jewelry. And I create babies."

She calls herself "a zany Erma Bombeck," and says if you knew what it was like growing up in the Spielberg home in Phoenix you'd know why.

"My mother was crazy; she'd let us do anything. She'd do anything. One time, Steve wanted to film a maid who was supposed to have blown up cherries jubilee in a pressure cooker. My mom let him use the kitchen and even helped fling canned cherry pie filling on the walls."

She thinks Steve, more than anyone in the family, combines her mother's whimsical creativity and her father's technical genius. "He was so patient with Steve. They used to sit for hours and splice movies."

She says her whole family keeps in close contact (her mother called during the interview) and she flies out to Hollywood four or five times a year. Recently she went to London to watch the filming of her brother's latest, produced with George Lucas, "Indiana Jones and the Temple of Doom."

When she was seven months pregnant she went to the White House for a private screening of "E.T." and after Uri was born he got a personal letter from President Reagan. In July her brother asked a friend of his -- Michael Jackson -- to get her tickets to the Jackson's New York tour concert. The most comforting advantage is the security of knowing that her brother would always help her out financially, if necessary.

But she is becoming increasingly concerned about publicizing her connection with her older brother, especially since her mother was threatened during the Olympics and had to hire a bodyguard.

She asked not to reveal her married name "because you never know what people might do."

She still fancies herself and her brother as oversized kids. "We'll never grow up," she says. Even at her wedding, "Steve grabbed the 8mm camera from the photographer and started filming us upside down." An Older Brother's Role

As Ronald Hoffman sits in his Treasury Department office surrounded by economics books and stacks of stapled pages, he occasionally looks out the window that directly faces the White House.

It was in there that the movie he loves to talk about began -- "the movie" being "All the President's Men," in which his brother, Dustin Hoffman, played Washington Post reporter Carl Bernstein. In fact, he says he helped his brother get the role opposite Robert Redford:

"I heard Woodward was writing a book about Watergate and so I called him up and asked for a copy. He sent me a Xeroxed copy with felt-tip pen cross-outs and I read it all in one night and called my brother and said, 'This is fantastic.' "

After the filming began, Ronald Hoffman stayed involved with the movie. Because he was on the Council of Economic Advisers in the Nixon administration and worked in the Old Executive Office Building in 1972 and 1973, he commented on the dialogue, checking to see if there was "logical character development" and if the "office looks" were right.

He continues to read scripts for his brother, though he has no desire to return to the acting he did when he was 6 years old.

"My mother tried to push me into it, even though I had no interest in show business," says Ronald Hoffman, at 53, six years older than his only brother. "She used to drag me around the movie lots where my father worked. He was in charge of the props for Columbia Pictures, getting things like chairs, tables and, one time, a boatload full of bananas."

But Ronald Hoffman, now a senior staff economist at the Treasury Department, did not share his mother's "rich fantasy life about what went on in Hollywood." After being a child extra in "Mr. Smith Goes to Washington" he "retired" from the business.

His mother had other plans for his younger brother, Dustin. She wanted him to be a musician and started giving him piano lessons when he was 5. Why his brother went into acting, Ronald Hoffman says he is still not sure.

"He wasn't an obvious star," the older brother says. "He didn't stand out in the high school plays . . . and he certainly didn't have the looks . . . and he was little."

"My guess is that he had an artistic disposition and systematically applied his intellect to keep improving on the product." The Lawyer and the Actress

Mac Dunaway called her "Dorothy" or simply "Sister" even after she decided "Faye" would make a better stage name.

"It was sometime in high school. She just came home and dropped her first name," says Mac Dunaway, the managing partner in the Holland & Knight law firm overlooking Farragut Square and the brother of actress Dorothy "Faye" Dunaway.

"She has been starstruck since she was little. I remember being in 'Saturday Evening Ghost' with her in elementary school. Even then she had to do everything perfectly. We used to fight like cats and dogs. She was a straight-A student and a National Merit scholar and the teachers were always saying, 'Why can't you be more like your sister?' I was more interested in football."

With clear blue eyes matching his white-collared blue shirt, Dunaway, 41, resembles his older sister especially when he laughs, summoning the deep dimples that frame his smile. "I think we both remember the time I became physically dominant. She couldn't beat up on me anymore."

Married for 19 years and a resident of Chevy Chase Village, Mac Dunaway says, "Those rough times with Sister are long since past. Things that used to grate on you fade with the passage of time. You realize that family is the lasting relationship."

Along with being a friend, Faye Dunaway is also her brother's client. He draws up her contracts for film and stage performances. They visit frequently when she is working in New York and living in her apartment there. This July his three children flew to London to watch their aunt film the made-for-television movie "Ellis Island" with the late Richard Burton.

For both Faye Dunaway, 43, the star of the films "Chinatown" and "Network," and Mac Dunaway, who was heading off to his frequent golf and boating retreat, Hilton Head, S.C., times were not always so successful financially. "There was little extra money when we were growing up," said Mac Dunaway. "My father was in the Army and we were constantly moving around. But we learned to meet new people and deal with new situations and my mother always pushed us and told us to do whatever we want. She always said, 'Set your sights high.' "The Mondale 'Black Sheep'

Just blocks from the White House, William "Mort" Mondale, the self-proclaimed "black sheep of the Mondale family," sits in a quiet, sparsely furnished office at the headquarters of the National Education Association at 16th and M.

A program development manager for the NEA who spends most of his time training teachers, Mort Mondale, 49, says he is unlike his two older brothers. He does not have a graduate degree and has "wandered from one job to another living in different places." And, he says, "I got divorced. Fritz would never do that. He sticks to his decisions."

Taller, but with the same deep-set blue eyes as Walter Mondale, Mort Mondale says it's not easy being the brother of a presidential candidate, especially when you work at on organization that hands an important presidential endorsement to your brother.

"I have damn good credentials," says Mort Mondale, a music teacher in Minnesota for 22 years and the former president of the education association there. "It angers me when people say I got this job because of my brother or that he got his endorsement because of me."

He says it's also hard to get used to the fact that people get mad at him because of his brother's stances. Recently he unlisted his phone in Alexandria because he and his wife were getting obscene phone calls in the middle of the night.

"Sometimes you just want to be left alone, like after San Francisco," he says. "You start to get paranoid. Why all of a sudden are old friends calling up? Even dear friends set us up at parties -- one minute we're guests and the next we're on stage."

What happens if Mondale and Ferraro win in November? Says Mort Mondale, "It makes me tired to think about how my life will change."

Though he says he is much more prone to "stirring up trouble" than his political brother, Mort Mondale says his brother wasn't above performing his own antics when he was young. "He tipped over outhouses one Halloween," he recalls.He says his brother lived up to the comment under his high school yearbook picture: "A little nonsense now and then is relished by the best of men."

One of the more recent was the first Thanksgiving he moved to the vice presidential mansion. "He greeted us at the door with black tails, a clashy blue shirt and tennis shoes. Then during the dinner, he kept throwing turkey bones at my wife's plate. He's a lot of fun in private."