What might have been a typically on-the-nose socially-conscious TV-style docudrama about the 1967 Supreme Court decision striking down state laws prohibiting interracial marriage instead proves a genuinely moving human drama in Jeff Nichols’ “Loving.” The key to the film’s success is simply reticence—in Nichols’ writing and direction and in the acting across the board, but especially in the performances of Joel Edgerton and Ruth Negga as Richard and Mildred Loving, the Virginia couple whose surname serendipitously reflected the deep emotion that bound them together over years of legal persecution.

The facts of the Lovings’ story are simply told. Unable to marry in their native state, Richard and Ruth traveled to Washington. D.C. in 1958 for the ceremony and then returned home. There they were arrested one night as they slept by the local sheriff, and the judge offered them a deal arranged by their lawyer—their one-year jail sentence would be set aside if they agreed to leave Virginia for twenty-five years. They moved to Washington, but weren’t happy there, and a return to Virginia for the birth of their first child nearly landed them in jail before they were permitted to go back to the capital. Mildred especially longed for the countryside, being especially concerned about the city’s effect on their growing family, and eventually worked up the courage to write Attorney General Robert Kennedy asking for help. He referred her letter to the ACLU, and young lawyer Bernie Cohen took up the case, eventually presenting it to the Supreme Court after a series of defeats in the state judicial system; during the long process the national press became involved, with Life magazine publishing a story about their plight. (Michael Shannon, a Nichols favorite, appears here as photographer Grey Villet, who came to their farmhouse to shoot some stills for it.) Finally in 1967 the case was decided in the Lovings’ favor, and they could live in Virginia without fear of being arrested.

This story has been told before—in a 1996 telefilm, “Mr. and Mrs. Loving,” with Timothy Hutton and Lela Rochon that was well received (though Mildred noted its many inaccuracies—Richard had died in a car accident in 1975, and never saw it) and in a 2012 HBO documentary, “The Loving Story,” which Nichols employed as a source. But this version is exceptional. The writer-director proves himself a master of simmering tension, letting the story unfold at a measured pace without histrionics; even the villains of the piece—Marton Csokas’ sheriff, David Jensen’s judge, Bill Kamp’s home-town lawyer—are presented as more misguided than malicious, people born into a traditional worldview that they can’t even dream of questioning. As Cohen, Nick Kroll, as well as Jon Bass as his associate Phil Hirschkop, play their parts with a deadpan comic tone that emphasizes a deep well of uncertainty and immaturity that they desperately try to hide from their clients. And while Shannon brings a sudden burst of energy to his scenes, the other supporting players—particularly Sharon Blackwood as Richard’s hardworking, laconic mother (who, among other things, is a midwife) and Winter-Lee Holland and Chistopher Mann as Mildred’s mother and father—keep their emotions well in check, though Terri Abney, as Mildred’s sister, and Alano Miller, as the Lovings’ friend Raymond, are given moments of greater volubility.

The quality of restraint shows up most notably, though, in the performances by Edgerton and Negga. Richard was a naturally taciturn, rather stoic fellow, and Edgerton, who can be a very volatile actor, embraces the man’s quiet, undemonstrative personality. Negga is almost ethereally soulful; though in the end she is the more activist of the two, her steely resolve is of an uncommonly gentle sort, watchful and unassuming. The expressions of affection between the two are modest, too, although their slightest glance and gesture is suggestive of the abiding love that allows them to continue their struggle over so long a period without losing faith in one another. It’s characteristic that in the end they decline to attend the Supreme Court proceedings, which allows Nichols to exercise reticence to the very end, presenting the outcome without the fanfare another director would have been tempted to bring to it.

The production is in every respect a mirror of the Lovings’ personalities, with cinematography (Adam Stone), editing (Julie Monroe), production design (Chad Keith), sets (Adam Willis) and costumes (Erin Benach) that are discreetly on target without calling attention to themselves. David Wingo’s background score, all strings, is similarly understated.

For some “Loving” may feel overly subdued in telling such a major civil rights story in such a low-key fashion, but Nichols’ gently intense approach is true to the character of the couple that made history without meaning to.