THE ALL-TRUE TRAVELS AND ADVENTURES OF LIDIE NEWTON.<i> By Jane Smiley</i> .<i> Alfred A. Knopf: 452 pp., $26</i>

Why the current fascination among novelists with the years bracketing the Civil War? Could it be fallout from Ken Burns’ Civil War documentary? The allure of a powerful moral issue set against the backdrop of compelling drama? Last year brought us Charles Frazier’s “Cold Mountain,” a prizewinning epic about a wounded Confederate soldier’s trek home to his beloved, and this year we have Russell Banks’ “Cloudsplitter,” about the abolitionist crusader John Brown. And now, four years after her own Pulitzer Prize winner, “A Thousand Acres,” comes Jane Smiley’s “The All-True Travels and Adventures of Lidie Newton.” A confluence of factors in mid-19th century Kansas--plucky pioneers with a moral mission who moved westward into a situation ripe with conflict--no doubt drew Smiley to this period.

Smiley’s ninth book of fiction is a memoir focusing on the action-packed, life-altering 21st year of a feisty heroine from Quincy, Ill., who marries a Yankee abolitionist and accompanies him to Kansas Territory. There, a fight that presages the Civil War is waging between Free Staters and Missourians over whether the new state will abide slavery. Smiley’s novel is a rousing, grippingly paced historical saga, but it manages at the same time--in classic Smiley fashion--to also be a touching portrait of marital love, an account of personal growth from ideological ambivalence to strong convictions and a searching inquiry into complex moral issues.

Smiley starts on relatively solid, simple moral ground, at least by contemporary standards: Her characters are emphatically not “sound on the goose question,” meaning they don’t accept slavery. But, as they are transformed by unfolding events that constantly surprise them, she quickly moves from this position into grayer, much more interesting areas: How far should one go in the name of beliefs? How tolerant should one be of others’ values, particularly values you find abhorrent? Is territoriality justifiable? Is theft in the name of a cause justifiable? Is it OK to steal from people who have been good to you, even if you don’t believe that what you’re taking--a slave--can rightly be considered property at all? Is revenge justified? Are there circumstances in which killing is justifiable?

Lydia Harkness is a large, plain woman of 20 who has been in the care of her narrow-minded older half-sisters since her mother’s death seven years ago. To their despair, she prefers horseback-riding, shooting, swimming and writing to sewing and housework. Her family is eager to marry her off, even to an abolitionist from Massachusetts passing through on his way to Kansas Territory. The year is 1855, and Kansas is not yet part of the union. Abolitionists from the North, like 30-year-old Thomas Newton, are flocking to what has been touted in fliers as a land of mild climate and major opportunity in the hopes of keeping it slave-free. Because her options are few and she is an adventurer at heart, and because she is drawn to Thomas’ levelheadedness and “air of amusement,” Lydia decides somewhat impulsively to join him.

What the newlyweds come up against in the territory is “something alien and unexpected.” They find a harsh climate and an inflammatory situation between the pro-slavery Missourians, depicted as “obdurate and threatening” drunken “Border Ruffians” and the more genteel Northerners. Smiley convincingly details the many stages of confrontation as well as the financial and practical aspects of eking out a subsistence living, whether crammed into shared rooms in the lively, growing town of Lawrence or alone on an isolated claim on the windy prairie in a rough 12-by-12-foot windowless cabin. Despite the dangers and hardships, Lydia and Thomas gradually come to know and respect one another and to feel “safe in the wilderness of space and nuptial contentment.” The lighthearted scenes of sweet domestic intimacy spent reading Emerson, Stowe and Thoreau or talking teasingly about relations between the sexes are particularly charming.

There are constant tension and continuous clashes with the mean-tempered, intemperate Missourians. These include ambushes by border patrols and pogrom-like sackings as well as threatened retaliations to atrocities said to have been committed by abolitionists including John Brown. Smiley effectively intersperses small, carefully wrought domestic quarrels that arise between the “disputatious” Lydia, who wants to quash the enemy, and her sometimes frustratingly restrained, judicious husband.

When Thomas is shot in cold blood along with Lydia’s beloved horse, it is no surprise that her first reaction is to seek revenge. And it is utterly in character that she should disguise herself as a boy to search for the killers, a development that enables Smiley to further highlight the inequalities women suffered then. It is also no surprise that Lydia has internalized Thomas’ “desire to act on principle” and finds herself weighing her every move by wondering what her husband would think. “What to do for Thomas, what to do that he would not have disapproved of, how to honor him, even how to think of him, was a hot little nut of a question that I turned over and over, trying to crack, day after day,” she tells the reader. When she collapses after a miscarriage and is taken in by slaveholding Missourians, whose principles she finds loathsome but who are unfailingly kind to her, she realizes that issues aren’t as simple as she thought.

The voice Smiley creates for her sympathetic and wonderfully human heroine is sharp, engaging, wry and wise. Also right on the mark are the chapter headings that never give away too much (“I See the Bottom of the Well,” “I Sully My Character”) and the many distinctive characters, including Lydia’s wild soul mate of a nephew, Frank, who seems to have wandered off the pages of Mark Twain, with his ubiquitous “see-gar stub” protruding from his mouth.

The intricate emotional analysis for which Smiley has become justly celebrated, tracing characters’ feelings as they fluctuate and evolve with the precision of fine needlework, is much in evidence in “Lidie Newton.” She is as adept at capturing the subtle nuances of relationships as she is at chronicling complex political activity. This is a gripping story about love, fortitude and convictions that are worth fighting for regardless of the outcome.