Always intense, actress Jane Wyman in 1948 was devoting every waking moment to her preparation for the role of the deaf-mute in the film "Johnny Belinda," which would win her an Academy Award.

Her husband, an actor named Ronald Reagan, had complained to the press about her single-mindedness. But their daughter Maureen, a restless, bubbly 7-year-old, quickly and enthusiastically absorbed her mother's intensity. Wyman said, as she learned the deaf-mute's gestures, Maureen "would run around the house practicing sign language," and still remembers much of it today.

Recent stories about Maureen Elizabeth Reagan, the elder child of Wyman and the man who is now president of the United States, have dwelt on her last name, her connection with her father. But to many of her friends and to her brother, Michael, she is much more her mother's child, a serious, impatient, sometimes moody bundle of energy who has now, at the age of 41, set her sights on a seat in the U.S. Senate.

Michael Reagan, four years younger than his sister, comes across light and easy, like his father. He jokes, laughs easily, answers a telephone call from a reporter he does not know with "What have I done now?" His big sister also jokes and loves company, but she exudes a sense of emotions held in check. Her laugh is low, loud and staccato, a machine-gun burst across her interlocutor's bow.

On the wall of her den, she has posted a favorite plastic embossed cartoon of two buzzards salivating. One says to the other: "Patience, my a--! I'm going to kill something."

When Maureen Reagan was 7 her parents were divorced and she was sent to boarding school, which, she said, "makes you grow up pretty fast." "I guess it's unusual to be at a very young age and realize you have to take care of yourself and make your own decisions, but then if we had lived at home it would have been the same because my mother's favorite line was, 'If I get hit by a Mack truck tomorrow you're going to have to take care of yourself.' "

From early on her unconventionality and independence have seemed to contrast with the general impression of her easygoing father, but both have been gregarious people fascinated with politics, and politics has been a career much harder for her as a woman to pursue. The coming of age of Maureen Reagan also reveals not only the difficulties of having a famous name (her brother says it has hurt her politically) but also the ability of Ronald Reagan to handle with aplomb the passions and intensity of his most openly intense child.

A convinced Republican at the age of 11, she later was shocked to learn that her father still considered himself a Democrat. At 18, she dropped out of college against her father's frequently expressed wish. She tried one marriage at age 20, and then another at age 23, before waiting nearly two decades to marry a third time to a man a decade younger.

If Maureen Reagan's run for the Senate seat from California is one more annoyance heaped on the president by his headstrong eldest offspring, he gives little sign of it. He enjoys her company, takes her in stride and makes small jokes about wishing she wouldn't run. To Maureen, this is typical deprecatory Reagan humor: Spying her in the Oval Office this cold winter, he said, "If you can't bring the sunshine, would you just stay home?" He also, she says, swiftly lectured aides who had violated his neutrality rule by being hostile toward her Senate bid in the press.

After her parents' divorce, she said, "I was very upset." But "both my parents were determined that we would have as normal an atmosphere as possible. So in the intervening years until my father and Nancy married, he would always be at our house at Christmas, would share holidays, and so there was always a family feeling." As Wyman's acting career climbed and Reagan's declined, there were times when Maureen and Michael would see more of their father than of their mother. He would take them to his ranch for the weekend. "There was a tremendous amount of time spent."

After 20 years as an actress, singer, radio talk show host and campaigner, Maureen Reagan has developed an effective, well-modulated speaking style, but when someone tried to kill her father a year ago, she briefly lost control: "This CANNOT, this WILL NOT, happen to another president!" she said in front of the cameras, her voice breaking with rage.

That Extra Dimension

Over many years of campaigning for her father, other California politicians and now herself, she has given the Reagan name an extra dimension, useful to her father. Hers is a conservative, business-oriented Reaganism which can still support the Equal Rights Amendment, the right to choice on abortion and some kind of restriction on handgun use. Little of the resentment toward the Ronald and Nancy Reagan expensive life style can be visited on a daughter who lives with her husband in a $600-a-month two-bedroom apartment in west Los Angeles and drives a dirty 1978 Mustang.

She admits to trouble raising money. She had to cancel a contract with one leading campaign management group and suffer publicity about her uncle Neil Reagan endorsing one of her opponents and calling her effort "hopeless." She is fourth in the polls, with only 9 percent, but says her growing network of volunteers will help her win the primary in June. A longtime Reagan observer, who insists Reagan is as much like her father as her mother, said her determination to stick with a losing campaign grows from the same spunk her father is showing in sticking with his economic program against widespread opposition.Her opponents, while complimenting her campaign abilities, say she is living on name identification. "Maureen would not be in this race if her name were Maureen Murphy," said Rep. Robert Dornan, currently in fifth place in the race. He says the same thing about front-runner Rep. Barry Goldwater Jr.

She pushes hard for local businesses to pick up lunch, sports and other school programs hurt by federal budget cuts. She rankles at White House staffers who discount the impact of a threatened $100 cut to Social Security recipients--"it's the difference between eating and not eating," she says. She is deeply involved in programs for disabled veterans. Recently she missed part of an important fund-raiser for her severely under-financed campaign because she was absorbed in working with an organization that finds jobs for delinquent youths.

"I'm a people person," she said, "I don't know how to deal with anything else but people."

"I think probably that the only weakness that there is, in a political sense for Maureen, is that she can care too much," said her husband Dennis Revell, 29, a recent law school graduate and businessman who for the moment acts as her campaign director. He is tall, slim, and gracious, seemingly calmer and quieter than his wife. In his presence, she can be as demonstrative and coy as a slightly worldly wise high school cheerleader, clutching his hand and gleefully recounting the delights of "playing kissy-face" in the back seat when the Secret Service does the driving.

Revell said he learned something about the press in his earlier years as a political organizer and anticipated some of the attention his marriage has brought him, although he was still surprised to see reporters lined up on Wilshire Boulevard when he emerged from his wedding. He deflated a budding controversy by quickly dismissing an employment agent who had, without authorization, referred to Revell's Reaganconnections. As for the differences between his and his wife's ages, "I don't think people are concerned about that these days."

He and his wife eat out a lot, but he cannot approach his wife's passion for food of all kinds. Even the menu of the Bel Air Sands Hotel's Caribbean Terrace, off the San Diego Freeway, drew her considerable attention. "Now I'm torn," she said. "I was going to have scrambled eggs with tomatoes, but then I saw the french toast." The french toast with sausage well-done and coffee won out. "Sometimes I think we go to movies just so we can eat popcorn," said Revell, eyeing his wife. She launched into a vivid description of the freshly popped kernels served at the Palms Theater on Motor Avenue, a favorite haunt.

She dates her enthusiasm for politics from the first gavel-to-gavel television coverage for the national conventions in 1952, when she was 11. She liked the Republicans better, she says now in a gale of laughter, because they seemed better organized: "A beautiful summer sun outside and I was glued to the television. My mother thought I was completely insane . . . About a week later they found me knocking on doors asking people if they were going to vote for Dwight Eisenhower." Michael, her adopted brother, and she had been sent to the Chadwick School in Palos Verdes. She spent a year at Emerson Junior High School in Los Angeles before going on to high school at Immaculate Heart in Hollywood.

She and her mother and brother converted to Catholicism when she was in high school (she is a Lutheran now) but the hard rules of the nuns did not suit her temperament. On a school retreat election night in 1956, she was prohibited from loud talk or listening to the radio. She paid dearly for the yell of joy she let out when the nun asked the students to pray for President Eisenhower and his second term.

Her mother, though now a registered Republican, "has never been politically active." Maureen Reagan saw less of her father when she reached her teens, "but I thought he was a Republican, he sounded like a Republican." When someone remarked, as she was stuffing envelopes for Richard Nixon in 1960, that it was too bad her father was a Democrat, she was surprised and called him. "Are you a Democrat?" she asked. "Yes," said her father, who had not yet switched parties. "What did you do that for?" replied his stunned daughter.

'Patience My Foot!'

After a year of college at Marymount in Arlington, she dropped out and got a job as a secretary in Washington. Asked why, she repeats her motto, sanitized for general audiences: " 'Patience my foot! I'm going to kill something.' I just wanted to do something, be somewhere. I thought $60 a week was more money than I'd ever see in my life." She said education for women in those days was slanted toward "getting a Mrs. degree . . . I wanted to be an actress, that's what I wanted out of life, and I felt to be an actress you had to know a little something about the world."

Her parents "were not thrilled," she said. "You have to understand, my father was the first person in his family ever to go to college." He worked as a lifeguard, waited on tables at the dormitory, doing whatever was necessary to put not only himself but also his older brother through school, she said. Yet, Maureen Reagan points out, his four children, all infected with a certain amount of restlessness, have never finished college. She credits her father with "a great deal of flexibility" in dealing with these rebellions: "When I left school, my father said, 'Well, write if you get work.' "

Asked who the man she married at 20 was, she said: "A jerk."

"Was he a lawyer, a . . . "

"That's all I'm going to tell you, he was a jerk."

Michael Reagan said his sister's first husband was a District of Columbia policeman. The marriage lasted less than a year. She then met a marine officer, who later left the service to practice law, but that marriage lasted only three years.

Domestic life did not suit her. "That idea was foisted on me, but it wasn't my idea," she said, "and I think that's something people should choose and not be forced into. The importance of homemaking and mothering is choice." She performed in local theater in Washington, then returned to California to work "in nightclubs . . ." she paused, " . . . singing." She paused again, " . . . sometimes well." A few acting parts came, "but there was such an upheaval in the business at that time, trying to get parts for women, and you had generations of women competing against each other. I just didn't want to do it anymore." She became a popular talk-show host on Los Angeles radio station KABC, a right-of-center Republican woman to balance the station's liberal-leaning male star, Michael Jackson.

The need for more job training and health care for veterans kept coming up. In 1969, wearing "the highest heels you could find and a miniskirt," she had joined a USO tour of Vietnam as a country rock singer. To this day she can tick off the names of the firebases she visited. It became clear to her, talking to soldiers then and years afterward, that not enough was being done, and at the height of the veterans protests over the closing of the veterans service centers last year she again personally lobbied her father to do something. "We're going to be fighting this problem for the next 20 years, unless we come to grips with it," she said. "How do we entice people into the military, in a volunteer structure, if we don't take care of the veterans?"

Republican State Assembly and Senate candidates in California began to ask her help in their campaigns. She had an attractive personality and a magic name, and she was good at encouraging support from women. "She's very articulate, never at a loss for words," said state Sen. Robert G. Beverly, a Redondo Beach Republican who got her help and now supports her U.S. Senate bid. "She has a lot of chits with people, from campaign workers."

Forgiving, Not Forgetting

"People who hurt my friends, I have a lot of trouble forgiving," she said. "People who hurt me, I tend to forgive, but I never forget."

She left radio work to edit a trade publication, Showcase U.S.A., promoting American products abroad. Until she resigned her job recently to pursue her Senate campaign, she conducted the business as she has her political career, an evangelist for what she sees as sensible social and economic problem solving based on personal responsibility. On the issue of letting women volunteer for combat duty, she eyes her undersized male interviewer and asks, "Why should you be doing a job for which you are not physically equipped, and a woman denied that job if she wants it even though she is physically equipped?"

On gun control, she recalls the time her mother, worried about crime in her apartment building, told a local police officer she was thinking of buying a gun. "Well, ma'am," the officer said, "you're not very big, and if a burglar came into your house you'd have an awful good chance that he'd kill you before you'd ever kill him. I'd suggest better locks." Said Jane Wyman's daughter, who wants gun owners to pass a gun-handling test, "People will spend hundreds of dollars for guns, but only 25 cents for a lock for the front door."

For a long time after her two marriages, she also showed this kind of caution about her personal life. When Michael Reagan married his wife Colleen in 1975, he said his sister was still "totally against marriage." But his marriage survived the grind of the 1976 and subsequent Reagan campaigns, which he says he thinks led her to change her mind.

"Dennis is the reason I changed my mind about getting married," she said. She met Revell at a Young Republicans meeting nine years ago; they have been seeing each other regularly about three years, and married last year. "She needs someone who is totally for her, which Dennis is, someone who gives her a pat on the back," said Michael Reagan.

She said she does not know if she and Revell will have children. If they do, she will not send them to boarding school, although she is quick to defend her mother's decision to do so 34 years ago. Her mother's contracts required her to work six days a week in those days, and "the hours were incredibly long, from 5 or 6 o'clock in the morning until well into the dark of night, so if you lived at home you lived at the behest of the housekeeper."

She revels in her independence, her ability to communicate, and makes a family joke of her hold on youth, encouraging each of the other three Reagan children to refer to her as their younger sister. An interviewer mentioned that people were sometimes confused to find a president married to a woman as domestic as Nancy Reagan, yet with a daughter as undomestic as Maureen.

Maureen Reagan flashed her largest grin. "I'm not a political wife," she said.