By Jennifer Johnston Viking. 132 pp. $15.95

IRELAND does not let its people go. While other writers may cast around for a subject, the writer in Ireland is propelled by the daily experience of betrayal, witness to the murderous, stubborn anger born generations ago when two rights came together and made a terrible wrong. There are so many layers to the conflict, cross raised against cross, flag against flag, class against class, so many deaths and so many hearts hardened into hatred that to sort it out is a work for angels. They have been few on the ground, but they do exist, and the helpless beating of their wings is the subject of this latest novel by the Anglo-Irish writer, Jennifer Johnston.

It is unfortunate for the American reader that Johnston has not received much attention on this side of the Atlantic. A writer with a deservedly high reputation in England and Ireland, Johnston in Fool's Sanctuary once more turns to the past, to the days immediately following World War I, to explore the people and the landscape of her troubled country.

Hers is the Ireland of the Protestant upper classes, country houses and the dreamy occupations of those who fear neither wolf nor the patriot Wolfe Tone on the doorstep. Sanctuary is what they call the estate where 18-year-old Miranda Martin lives, looking out on the Irish Sea. Her father, gentle and remote, devotes his days to reclaiming the land, building drains, planting trees, offering schemes for the government to take it over and set up a farmer's cooperative. Bolshevism, an English visitor exclaims, and Miranda responds curiously, "Is it? . . . I thought Bolshevism was something really dangerous."

The world is gathering itself up around Sanctuary, preparing to argue its way in with the terrible logic of violence: this, having been done, that must now follow. Cathal, Irish Catholic friend and lover of the young Miranda, returns from university in Dublin caught up in the approaching rebellion and cautioning her that "it's like sparks are coming out of people's heads. Everything looks normal, but when you breathe in . . . . "

As Miranda and Cathal sport on the beach, he taking care not to wet his Dublin shoes, they are watched by two men. Miranda's older brother, Andrew, is home from England, wearing the King's uniform and carrying the King's coin. Although he has come to visit his home with a fellow officer, he has forged his own separations -- cutting himself off from his father and from Ireland. Cathal, his boyhood friend, is someone to sneer at, and of Dublin he rages that "I'd blow the whole damn city to smithereens and all the damn traitors and half-traitors with it. Poum."

"Poor Andrew . . . held together with string," thinks Miranda years later, meeting him in London and recognizing that with Andrew, as with Ireland, "somewhere among the misunderstandings and the ghosts and the fear there was love."

JOHNSTON HAS told her story backwards, beginning with the old age of Miranda, who ever after that terrible weekend has held herself apart from life, shut away in sacrifice and atonement. What she has been guilty of is innocence, and in Ireland the innocent blow up with the guilty.

Johnston writes a tight and a beautiful prose, weaving past into present. Fool's Sanctuary is a short novel, and Johnston acts the role of a wizard without time to waste, using words as a wand to tap her characters into life. She offers us people who are as vivid as the drama that surrounds them, and the helplessness with which they let love die does not seem strange to a generation that has learned to see Ireland as a place where one grief piles onto the last, and the word that might bring peace cannot be said because, as Miranda remembers, "My tongue seemed to be filling my mouth, no word could possibly pass the heap of it." In Johnston's novel, as in her country, the words are not said and men march forth in fearful and hopeless bravery. It is not just Cathal and his fate that moves the reader to tears; it is all of the characters, caught in a conflict they can't control. If there were a guardian angel following the lovers across the sands of the Irish Sea, the angel, too, must grieve.Susan Dooley is a Washington writer and critic.