The only thing more distressing than the size of America’s prison system is its racist function. According to the NAACP, African Americans are incarcerated at more than five times the rate of whites — a situation that effectively disenfranchises black voters, permanently wrecks millions of families and endlessly perpetuates a class structure forged in the antebellum era.

(Algonquin)

Just how directly our modern penal institutions descended from American slavery was illustrated most recently in Jesmyn Ward’s novel “Sing, Unburied, Sing,” which won the National Book Award last fall. In a modern-day story that takes place during a road trip to and from the Mississippi State Penitentiary, Ward dips back into the history of Parchman Farm, where armed guards once oversaw prisoners — some merely children — sentenced to plantation labor.

Tayari Jones’s new novel, “An American Marriage,” makes a surprising companion to “Sing, Unburied, Sing.” Her African American characters would seem to inhabit a different world: They’re college-educated, gainfully employed, upwardly mobile; they haven’t been flailed by poverty or caught by the hooks of addiction. But they are black, and in America, that fact trumps everything else. The justice system that rips apart their lives is the same one that ruins the desperate family in Ward’s novel.

“An American Marriage” opens early in the marriage of Roy Hamilton and Celestial Davenport. Roy is an ambitious, handsome man with a bit of a wandering eye, but he’s devoted to Celestial and determined to support her the way her wealthy parents did. Celestial, meanwhile, is drawn to Roy’s sexy demeanor but suspicious of his fidelity. Although she’s grateful for his encouragement of her nascent art business, she’s sensitive to his condescension. Like any young couple, they’re figuring out who they are and how their household will work.

“I know that there are those out there who would say that our marriage was in trouble,” Roy says. “People have a lot of things to say when they don’t know what goes on behind closed doors, up under the covers, and between night and morning. But as a witness to, and even a member of, our relationship, I’m convinced that it was the opposite.”

In the story that unfolds, we become another witness to this relationship, but that only gives us a fuller sense of the essential mystery of marriage and of the truism that no marriage takes place in a vacuum. Each character speaks directly to us, alternating chapter by chapter, as though Roy and Celestial are pleading for our understanding — and our forgiveness. But Jones offers no clear lines of culpability here, which is what makes “An American Marriage” so compelling.

Roy and Celestial are married just a year when police burst into their hotel room and arrest Roy for aggravated sexual assault of an old woman down the hall. Celestial knows — just as we do — that Roy is innocent, but he’s convicted and sentenced to 12 years in prison. In that moment, the marriage that Roy and Celestial had begun building and the future they had imagined for themselves collapse.

Author Tayari Jones. (Nina Subin)

Jones makes a series of daring creative choices in this, her fourth novel. “An American Marriage” isn’t a story in which our racist system of justice is the dramatic focus of the plot; that system is simply the toxic landscape these characters inhabit. When Roy says, “What happened to me could happen to anybody,” his best friend shoots back, “You think I don’t know that? I been black all my life.” Similarly, the violent attack in the hotel, Roy’s botched trial, the efforts to win his release, and especially his ordeal while incarcerated all could have provided material for an exciting if familiar literary thriller. But Jones has chosen to minimize those elements for something intimate and introspective: a story about the unpredictable ways love ferments in the airless conditions of forced separation.

For 50 pages, Roy and Celestial stop speaking directly to us and, instead, write letters to each other. Jones makes the most of the epistolary form, which was once so common in novels. Both Roy and Celestial feel the awkwardness of this antique mode. They struggle self-consciously with the mechanics of articulating their thoughts on paper. Roy, particularly, shifts erratically from strained jokes to naked expressions of longing:

“This love letter thing is uphill for me,” he writes. “I have never even seen one unless you count the third grade: Do you like me ___ yes ___ no. (Don’t answer that, ha!) A love letter is supposed to be like music or like Shakespeare, but I don’t know anything about Shakespeare. But for real, I want to tell you what you mean to me, but it’s like trying to count the seconds of a day on your fingers and toes.”

Prison creates such asymmetrical conditions for married people. Roy has lots of empty time to idealize his relationship with Celestial, but she has just as much time to reconsider who Roy really is and how she wants to spend her life.

“Dear Roy,” she writes early in his incarceration, “I’m writing this letter sitting at the kitchen table. I’m alone in a way that’s more than the fact that I am the only living person within these walls. Up until now, I thought I knew what was and wasn’t possible. Maybe that’s what innocence is, having no way to predict the pain of the future.”

As Roy and Celestial move into that painful future, Jones forces us to consider what they really owe each other. Roy imagines that a man in his position “should receive some sort of special consideration” — both a license to cheat and an extra claim on his wife’s affections. But what really are the boundaries of Celestial’s responsibilities? Must she provide unwavering devotion sufficient to compensate for a prejudiced culture? Or is she just as free as any other woman to fall out of love, to reject a life that chance and racism have conspired to draw for her?

These are punishing questions, but they’re spun with tender patience by Jones, who cradles each of these characters in a story that pulls our sympathies in different directions. She never ignores their flaws, their perfectly human tendency toward self-justification, but she also captures their longing to be kind, to be just, to somehow behave well despite the contradictory desires of the heart.

Ron Charles is the editor of Book World.

An American Marriage

By Tayari Jones

Algonquin. 320 pp. $26.95