Television forgives us our trespasses. It hardly dares to bring them up.

Prime-time entertainment distances social problems and gives them tidy escapist solutions. Documentaries that may seem troubling and penetrating also can have an additional soothing side: in your past year, nonfiction network TV has managed to suggest that most of the arson and urban violence in the United States occurs in the South Bronx.

There are exceptions. There are times when television confronts us with disorders that hit close to home, and few hit closer than "Battered," an NBC movie about wife-beating that airs tonight at 9 on Channel 4.

The importance of the film has to do with more than its nerve in bringing up the discomfronting subject of domestic violence, a problem doubly acute in that even its victims shrink from discussing it. In addition, "Battered" has sparks of insight into the whole dilemma of human relations that go awry, peace negotiations that crumble, and rational beings who cross over the threshhold into unthinking acts of physical cruelty. It is about why we insist on continuing to harm one another.

Karen Grassle, who stars in the film and who cowrote the script with Cynthia Lovelace Sears, is seen weekly as mother Caroline Ingalls on NBC's most successful series, "Little House on the Prairie," a doggedly pleasant and pacifying romanticization of American home life in another and virtually imaginary century. People have problems on that show - they go blind, for instance - but they don't mistreat or betray one another. All threats spring from the world outside.

"Little House" is an idealized version of family life," Grassle concedes. "I think it's because of my appearance on that show that I wanted to do something that had to do with contemporary problems. It was some kind of liberal guilt, I guess."

She smiles a very warm and reassuring smile. Her performance in the film - as a suburban housewife whose 10-year dream marriage reveals itself to be a fantasy with one vicious slap in the face - is tremendously affecting and believable, largely because the wife is not presented merely as a victim of abuse, but as someone who helped precipitate her own dilemma with a childlike outlook on what a marriage is and that a husband should be.

The film deals with two other couples whose paths cross during the story and whose homes are disrupted by variations on the same situation. A young actress named Chip Fields plays a wife who refuses to concede that her husband's fits of violence are anything other than fleeting abberrations. Indeed, she blames herself.

Grassle and Childs visited Washington last week to make a Hill appearance on behalf of H.R. 12299 - "the Domestic Violence Assistance Act of 1978" - which would set up an Office on Domestic Violence (under HEW) and a national tool-free hotline for victims of a crime that, for the most part, goes unpunished and unreported.

"We didn't do the program to support the bill," says Grassle."I started three years ago on a script, and we, Congress and I, were just chugging along on the same path. The actress in me was greedy for a good part, and I had a file of possible ideas. Then I met this woman journalist in Texas who filed me in on the realities of this problem and I was stunned. I said, 'This has to go on television.'

"The situation is so bad we have to face it. It's an epidemic - the single most unreported crime against women, and there are estimates that it occurs three times as often as rape. Something like 22 percent of all police fatalities occur when they're responding to domestic violence cases."

One problem for Grassle and her collaborator, and for director Peter Werner, was how to dramatize this violence without just adding to television's substantial body count. Of course, this is not comic-book stuff, and despite all the brawls and clobberings we have seen on TV, when Grassle is first struck by Mike Farrell, who plays her seemingly straight-arrow husband, it is a devastating and depressing jolt - even if the NBC promotion department has been clumsily using the scene in tawdry on-air ads for the program.

"There's so much violence on television, and it's so off-the-cuff, that we certainly didn't want to add to that," Grassle says. "You see all these shows that start with a rape or start with a beating. We did not want to encourage thinking of women as someone you assault. We very much didn't want to exploit violence in the course of supporting antiviolence."

In her role as the martial partner and sparring partner of LeVar Burton, Fields falls for her warrior husband's morning-after apologies: "I'm sorry. I don't know what gets into me. I hate myself for hurting you." It takes the coaxing of a friend to shake her from the notion that she is beaten by her husband because she has somehow failed him.

"Before we starting shooting, I'd talk with a girl on the phone who'd been through this kind of thing," Fields says. "She was a lot like me - black, 26 years old - and we'd talk, like, from 10 p.m. to 3 a.m. every night. And she could relate to everything that went on with my character in the script.

"I couldn't understand why she should be the one to feel guilty. And she said it was because her husband seemed like such a nice guy, so well liked in the community, so popular, that she'd rationalize the beatings to herself; 'It must be me.'"

The film is not just a tract against bullying hubbies. It shows the shadings of guilt on both sides, and the humiliations that accompany acts of violence within families - the mutual corrosion or obliteration of self-esteem, the way one act of violence makes others come easier. Grassle's character must also deal with a terror that society has conditioned within her, the fear of being alone, and with the belief that she cannot function without a strong and assertive man to take care of her.

In fact, the most moving of several scenes is when the husband goads his wife into recalling for friends how they met at a party and the wife begins to weep as she remembers how unreasoned and pathological her dependence and hero-worship were. She says, "I didn't want to be anywhere without him."

"Battered" is a morality play and suffers from some narrative awkwardness and occasionally rhetorical dialogue. Burton is disappointing with his absent-minded performance as Childs' husband; coincidentally, he is starring in a CBS movie tonight that airs simultaneously with "Battered," and may be over-extending himself as an actor.

Draft spats between Howard Duff and Joan Blondell, as a pair of rowdy old boozers, come off as incongruously comic, but Grassle says this was intentional, so that the tragedy that later befalls Blondell's character would have that much more impact. It may not work out just that way for viewers.

The intentions continually redeem faltering execution, however, and even the semblance of a "happy" ending doesn't impair the film's resourcefulness in dramatizing the very darkest sides of the American home and the American dream - institutions that television usually treats not just with kid gloves but with kiddie mitties.

"Battered" confronts horrors that most TV depictions of the American family pretend do not exist.

Some of the women in the film, like some of the battered wives in real life, end up at a communal shelter where they literally seek refuge from their marauding husbands. It sounds like another case of having given up on curing the causes of a problem and inventing a device to deal with the effects instead.