‘Loving” is a quietly radical movie. A portrait of Richard and Mildred Loving, who became unwitting activists for interracial marriage when they wed in 1958, this gentle, deeply affecting story dispenses with the usual conventions of stirring appeals to the audience’s social conscience.

Viewers expecting a climactic showdown at the United States Supreme Court — which in 1967 handed down the landmark decision bearing the Lovings’ name, declaring anti-miscegenation laws unconstitutional — or highly pitched speeches about civil rights, privacy and marriage equality will be surprised by a film that steadfastly avoids the most obvious and tempting theatrical manipulations. Instead, viewers are confronted by something far more revolutionary and transformative, in the form of two people’s devotion to each other, and the deep-seated psychological and state forces driven to derangement by that purest emotional truth.

Based on Nancy Buirski’s wonderful 2012 HBO documentary “The Loving Story” and judiciously dramatized by writer-director Jeff Nichols, “Loving” gets underway just as Richard (Joel Edgerton) and Mildred (Ruth Negga) decide to get married, after Mildred discovers she’s pregnant. A longtime couple in the rural town of Central Point, Va., Richard and Mildred reflect the organic ethnic integration of a community in which white, black and Native American citizens routinely befriended and relied on each other.

This film tells the true story of the courtship and marriage of Mildred Jeter, a black woman, and Richard Loving, a white man. Their interracial marriage was considered illegal in their home state of Virginia, and their case makes it to the Supreme Court. (  / Focus Features)

Because interracial marriage is still illegal in the commonwealth, Richard and Mildred get married in Washington, then move back in with her parents to begin raising a family of their own. Less than a month later, Caroline County Sheriff R. Garnett Brooks (Marton Csokas) is rousting them out of bed, snarling that the marriage license on the wall is “no good here” and taking the couple to jail, where Mildred is forced to languish for several days. Ordered by a judge to move out of Central Point for 25 years, they move to Washington where, in 1963, Mildred decides to write to Attorney General Robert F. Kennedy to see whether he can help them in their plight.

The rest is history, but Nichols trusts filmgoers to understand that. Rather than deliver a rote — if rousing — rehearsal of the facts of the Lovings’ case, he makes the counterintuitive decision to allow them to live in front of the camera, capturing the corn and bean fields they were born next to, the daily work they performed, the small kindnesses and everyday rituals that accrue into lifelong bonds at their strongest and most lasting. When the Lovings are forced to decamp to the noisy, assaultive D.C. streets, the viewer can feel the jolt of dislocation and share in Mildred’s longing. Like every classic saga, her appeal to higher powers had little to do with her own sense of importance or political grievance. She doesn’t want to be a symbol or a secular saint. She wants to go home.

Ruth Negga stars as Mildred Loving. (Ben Rothstein/Focus Features)

And make no mistake: “Loving” is very much Mildred’s story, as a slim, shy young woman who, by the end of the film, has found her own potent voice. Negga delivers a demure, nuanced performance as Mildred, who embraces the couple’s ACLU lawyers’ plans to take their case to federal court. As the rawboned, verbally reticent Richard, Edgerton bears an even more uncanny resemblance to his taciturn real-life character. (“Tell the judge I love my wife,” he says when he declines an invitation to attend the Supreme Court hearing of the case that bears his name.)

Nichols is too astute a filmmaker to be unaware of the analogies “Loving” invites regarding marriage equality, but he wisely leaves agendas and polemics behind. As he observed after the film’s North American premiere in Toronto in September, the Lovings didn’t get married as an act of defiance. They got married because they loved each other.

One of the most moving sequences in “Loving” is when Nichols reenacts a photo session with Life magazine photographer Grey Villet (Michael Shannon), who breaks down the couple’s stiffness by discreetly observing them washing dishes and watching television, Richard’s head on Mildred’s lap. That turned out to be an iconic image of the Sixties, and it possesses just as galvanizing an effect today, pointing up the irrationality of the forces arrayed against the pursuit of happiness at its most quotidian and innocuous.

Among the myriad ironies that animate “Loving,” perhaps the most cutting is when an official accuses Richard and Mildred of threatening “the peace and dignity of the commonwealth”: It’s difficult to imagine anyone more gracefully embodying those very principles. Intimate, moving and superbly underplayed, “Loving” is every bit as soft-spoken and subtly implacable as its protagonists. It lives up to its title as a noun and a verb, with elegant, undeniable simplicity.

PG-13. At area theaters. Contains mature thematic elements. 123 minutes.