Ask America's most accomplished actress which has been harder, acting or mothering, and she does not hesitate for an instant.

"Mothering. Definitely," she shoots back during a conversation on the eve of the premiere of her widely lauded new film, "One True Thing."

"Acting -- that's praise, money, fulfillment. Mothering -- they don't even say, Thank you.' They don't even clear the table unless you say, Excuuuse me . . . ' Real life, there's no comparison to acting. I can't really call acting work, since it's secretly so fun. Even the difficult things; it's satisfying to do the difficult things well.

"Acting isn't like real life. Life is about not being sure: Is this the right school for this kid? All those uncertainties."

Streep, 49, ought to know, having won two Academy Awards and been nominated 10 times over a 21-year career that's also included raising four children, one boy, three girls, now ages 18 to 7, in rural Connecticut.

That is why she was so drawn to the character she plays in "One True Thing," a traditional housewife, Kate Gulden. Kate reminded her of her own mother and was a departure from most of the characters she's played. "I think my mother is a great model. Women are often devalued if they're not in the workplace. If you're a housewife, you're presumed to be nothing. Well, yeah -- you try to run a household with imagination and verve."

Streep's mother, now 83, was a leftist activist and a sometime artist in New Jersey, then later became a Republican and a housewife. "She didn't have a big career, but she had a life she liked," says Streep. "She's really funny. She's full of light -- she lights up a room. I'm my Dad, more melancholy . . . " Streep pauses. "But they don't make movies about women that are happy. They have to be obsessed and neurotic."

Streep, of course, did not choose the life of her mother, but she found a memory of that time in the tale of "One True Thing," based on the book by former New York Times columnist Anna Quindlen. The film explores the complex relationship between mothers and daughters from across the divide of the feminist revolution and -- perhaps without meaning to -- gently prods the bruised consciousness of women still struggling to define their proper roles in the wake of a sexual liberation movement, a post-feminist backlash and a heightened New Age spirituality.

Kate Gulden is a prototypical homemaker from the postwar era, content and proud to be the emotional and physical anchor for her husband and two children. The film is set in 1987, and Kate has missed feminism completely (she was having kids in the '60s); she's still content to cook and bake and decorate Christmas trees in the town square with elaborate handmade ornaments.

Her daughter, Ellen Gulden, is a prototypical product of the end of the baby boom and a successful women's revolution, raised smart and proud and sure that she will accomplish anything she sets her mind to. So far so good: She's made it through Harvard, landed a job at a high-powered magazine in the world's most competitive news town and has wangled a major assignment to write about a senator. When her mother gets cancer, Ellen must abandon her Manhattan career to care for Kate.

But there is an emotional gap between mother and daughter. Ellen condescends to her mother for playing a subservient role. Kate accepts her daughter's barely veiled contempt -- she seems glad that Ellen can accomplish what she could not -- but beneath it exudes a kind of quiet wisdom that says: Someday, Eli, you'll understand.

What was true in "One True Thing's" 1987 is even more so in 1998, which is why the movie is sure to touch a chord with many women who see it. If anything, it's even tougher now for women to figure out their place in a society that sends mixed messages about roles and responsibilities.

Streep has grappled with career vs. kids for two decades (now she's dealing with aging parents, too), and has been prying toddlers off her leg to go off to movie sets since filming "Sophie's Choice" in 1982. When asked about this during a conversation at the Four Seasons Hotel this week, she sighs and closes her eyes and thinks back.

"I never made any choices, I just got pregnant a lot. And when I was done weaning a baby I'd start reading scripts," she says, clutching a long-cooled cappuccino. "I recognized myself in Eli. Actually, I felt like both of them, I've lived both those lives. My mom raised me to think that I could do anything that I wanted, and to want to do something."

Streep went to Vassar and then to Yale Drama School and was in the vanguard of the generation embracing the myth that women could "bring home the bacon/ Fry it up in a pan" (as that old perfume ad swore).

Except that Streep has actually done it rather successfully.

"Well," she says. "I take a lot of time off. So-called off.' When I'm not filming I'm working very, very, very hard." Dealing with things like orthodontia. Arguments with the school headmaster. Putting back together what's fallen apart in her absence. You may be surprised to learn that even movie stars have to yell at their kids to pick up their clothes.

But she's been home with her husband, sculptor Don Gummer, a lot; she only accepts roles that she deems worthy of removing herself from her other life. "I need to know there is a reason to take time out from the very intricate and exhausting and deeply interesting job of being with my kids and with my husband. To take four months and do a movie, it has to be worth it."

The graceful Streep, who has taken on the daunting challenge of finding happiness and fulfillment, is, not surprisingly, a role model for Renee Zellwegger. Acting opposite Streep was easy, says the young actress, because she completely became Kate Gulden. "It was not hard to believe that it was happening right there, right then," says the 29-year-old actress. She goes on, "I'm always really impressed with people who maintain a balance between their professional and personal lives. It's so hard to weigh what's important."

But Zellwegger knows she has yet to confront the hardest stuff in life and perhaps because of that, she didn't have much sympathy for her character -- at first. "I thought, I'd never be like this Ellen Gulden, she's so self-involved and blind.' I'd judge her," says the actress, speaking by phone as she got dressed for her movie premiere in Los Angeles. "It's almost comical. I thought, She's so completely unaware of how her actions affect other people.' I thought, I'd never, never behave that way. I'd never do that.' Then you think, Wait a minute -- did I? Have I?' And I'd get right on the phone with my mother and make sure I talked for more than five minutes." (In mid-interview, Zellwegger calls to her boyfriend in the next room, "Here -- I can sew that up.")

But it is not just women who have lived the characters' lives who respond to the film. Streep and Zellwegger have been attending screenings for women's groups in Dallas, Atlanta, San Francisco and other cities, and the post-film discussions have been heated and lengthy.

The film's producer, Jesse Beaton, has been mulling the film's messages and subtexts for months. She says, "We were all told you could have it all. And it's not true; it's not physically possible unless you can exist on 90 minutes of sleep a day."

She goes on, "I don't have children. I didn't really want them. But I have lots of friends who are trying to balance both things and are worn down and confused all the time because they're split, struggling to hold it together. And at the same time there are other women who woke up at 38 or 40 and are in shock that they are not completely fulfilled by their jobs. It took so much energy and effort to be successful that they have forgotten to have babies."

In some ways "One True Thing" is a celebration of the traditional and sometimes-denigrated values of making a home and raising children, since Kate Gulden is idealized as an intelligent and perfectly fulfilled human being, while the adored father turns out to have many hidden flaws.

But Ellen Gulden does not turn into her mother. She has grown and deepened as a human being and a woman by the end of the film, but she does not discard her writing career. For Streep, some of the rewards of having struggled to be both actress and mother are just beginning. Now she finds that her oldest child, 18-year-old Henry, asks, "Hey, Mom, why don't you do more movies? You could be working with some really interesting people. . . . "

"Hah!" Streep snorts. "I'm busy! And this was the same person who was draped on my leg at age 3 when I was going out the door to work."

Streep, who seems so wise in the film, says that in real life she is a long way from having all the answers.

"There is no road map for life. You don't know who's going to get sick, who'll be born with the thing that needs to be dealt with," she says. "All you can do is live inside your own life. In my life I'm grateful to have as much time as I've had at home, to work in the movies. I wouldn't trade the time I've had with my kids -- a lot of men don't get that. I encourage my daughters the way my mother did.

"But I really think my mother is a good model, you know. Her attitude is, You may as well be in a good mood, goddammit.' "

It's an attitude that, in the film, a dying Kate Gulden desperately tries to transmit to her driven daughter. Says Streep: "Your happiness is sitting in the room with you if you choose to see it there. If you don't, it's invisible and not there. I think that's true to a certain extent. You can locate it if you choose to, the happiness you already have." CAPTION: Meryl Streep: "My mom raised me to think that I could do anything that I wanted, and to want to do something." CAPTION: Meryl Streep, right, gives hug to Renee Zellwegger, who plays her daughter in "One True Thing," at New York premiere of their film.