Joyce Carol Oates’s new novel, “A Book of American Martyrs,” arrives splattered with our country’s hot blood. As the Republican Congress plots to cripple Planned Parenthood and the right to choose hinges on one vacant Supreme Court seat, “American Martyrs” probes all the wounds of our abortion debate. Indeed, it’s the most relevant book of Oates’s half-century-long career, a powerful reminder that fiction can be as timely as this morning’s tweets but infinitely more illuminating. For as often as we hear that some novel about a wealthy New Yorker suffering ennui is a story about “how we live now,” here is a novel that actually fulfills that promise, a story whose grasp is so wide and whose empathy is so boundless that it provides an ultrasound of the contemporary American soul.

The opening pages explode. Immediately we’re there, inside the head of Luther Dunphy, filled with the zeal of divine vengeance. “So swiftly the Lord executed my moments,” he thinks, “there was not time in the eyes of the enemy to register fear or alarm.” After telling his boss that he’ll be late for work, Luther drives to the Broome County Women’s Center in Muskegee Falls, Ohio, timing his trip to coincide with the arrival of the chief doctor, Gus Voorhees. As Gus gets out of his van, Luther raises his shotgun and shoots the doctor in the throat, “as if the Lord had dealt His wrath with a single smote of a great claw.”

[Book World: ‘The Accursed,’ by Joyce Carol Oates]

From that instant of violence — resembling the 1994 murder of physician John Britton and his guard in Pensacola, Fla. — Oates draws her own vast tale about righteousness both religious and secular. Spreading out over more than 700 pages, the novel has room to trace the events that motivated Luther before that deadly morning and to explore the penumbra cast by Gus’s death over the next decade. We come to know both men’s wives and children: the well-educated, liberal Voorheeses and the poor, devout Dunphys. They are American families so separated by opportunity and ideology that they could be living in different countries, but Oates’s sympathetic attention to the dimensions of their lives renders both with moving clarity.

The opening section stays close to Luther, the deadly activist who will initially strike most readers as a monster. But in the careful accruing of Oates’s narrative, he becomes something more real and complex: a father shattered by guilt, a husband incapable of arresting his wife’s depression, a carpenter bravely laboring through crippling pain. It’s no wonder that such trials would push him toward a search for redemption, a cause greater than himself. There’s a hypnotic dread and sadness running through Luther’s life that only the energy of a great cause could cure.

He confesses to us: “The possibility that the Lord God, Who has spoken to others and has shown the way in which His will might be fulfilled in the world of humankind, might have spoken at last to me — this was terrifying to me.” Encouraged by the “justifiable homicide” doctrine of a particularly strident antiabortionist, he concludes, “You, Luther Dunphy. You are the chosen one.”

This enraptured fanatic poses an existential challenge for America, a country predicated on a Declaration of Independence, a celebration of individuality, a tradition of radical self-reliance. In a sense, our national fiction began with Charles Brockden Brown’s “Wieland” (1798), a gothic novel about a man driven to murder by a voice he believes is divine. A modern master of gothic sensibilities, Oates is wrestling with a similar conundrum more than 200 years later: What voice is Luther really hearing?

The novel insists that Luther’s sense of mission is no less palpable than that felt by his victim, Gus Voorhees. In later chapters focusing on the doctor, we see a man driven by equally deep-seated ideals, just as convinced of the rightness of his cause as his most strident opponents are. His liberal mission brooks no compromise, no accommodation of others’ sensitivities nor even an acknowledgment of the risks he subjects himself to.

Joyce Carol Oates (Dustin Cohen)

It’s on this last point that the story moves toward the collateral victims of Dr. Voorhees’s murder and offers its most poignant insights. What will the doctor’s wife and children suffer by loving a man who refused to guard his own life more cautiously? What price will they pay by having their own lives forever viewed through the optics of the country’s abortion conflict?

Those questions come to dominate the novel as Oates shifts her focus to two girls: one a daughter of Dr. Voorhees, the other a daughter of Luther Dunphy. The lost children of American martyrs, they move in worlds so alien to each other that only we can see the filament of pain that connects them. Bright Naomi Voorhees struggles for years to construct a record of her father’s life, while plodding Dawn Dunphy pours her anger into becoming a professional fighter — a plotline that recalls Oates’s most unlikely book, “On Boxing,” published in 1987.

For “American Martyrs,” Oates has mastered an extraordinary form commensurate to her story’s breadth. The book is written in a structure fluid enough to move back and forth in time, to shift from first to third person without warning, sometimes breaking into italics as though this febrile text couldn’t contain the fervency of these words. We hear internal monologues, conversations, lectures and sermons, court transcripts, newspaper articles, phone calls, a college application, documentary footage, even a haunting passage of free verse composed of the pleas of Christian women secretly begging for abortions.

In these hyper-partisan times, we want to know, of course, is this a pro-choice novel or an antiabortion novel? Although Oates’s Twitter feed leaves little doubt about her personal views, as an artist, she’s far too good to allow her book to descend into such polemics, and gradually the story moves away from that endlessly cycling debate between evangelicals and civil libertarians. The Voorheeses may reflect her own ideals, but the Dunphys are treated with equal respect. Last fall at the National Book Festival in Washington, Oates reflected on these Christians who so aggressively oppose abortion: “I wouldn’t write about people that I didn’t like and respect,” she said. “I think they’re acting from their own idealism, which is, in some cases, extraordinarily courageous. I’m very fascinated by that kind of strange, perhaps tragic courage.”

To enter this masterpiece is to be captivated by the paradox of that tragic courage and to become invested in Oates’s search for some semblance of atonement, secular or divine. Regardless of your own faith or politics, the real miracle here is how, even after 700 pages, we can still be racing along, steeling ourselves for the very last line, a line we’re desperate to reach — but not too soon.

Ron Charles is the editor of Book World. You can follow him on Twitter @RonCharles.