“Junebug” is the story of a blue-state woman meeting her red-state in-laws – and the purple bruises that result. Madeleine (Embeth Davidtz) is the quintessential cosmopolitan. Born in Japan, raised in South Africa, she runs a gallery in Chicago specializing in outsider art. One day at an auction, her eyes lock on George (Alessandro Nivola), a young stud from North Carolina. Quicker than you can say “southern fried chicken,” they’re making out to the clipped rhythms of a Godardian credit sequence – an announcement of director Phil Morrison’s stylistic ambitions.

When Madeleine learns of a reclusive, self-taught painter based near George’s family home, the newlyweds head south, cultural baggage in tow. Mr. Morrison sketches in the family during their journey, establishing the pattern of tension, affection, and unspoken frustration that defines their personal and collective lives. The man of the house, Eugene (Scott Wilson), retires silently to his basement workshop, while his imposing wife Peg (Celia Weston) lords over the hearth, chain-smoking in brittle resignation.

Meanwhile, their son Johnny (Benjamin McKenzie) broods in the kitchen, tuning out the relentless yammering of his anxiously upbeat, extremely pregnant young wife Ashley (Amy Adams). Ashley is in a tizzy over the arrival of Madeleine, whom she imagines to be smart, thin, beautiful, and worldly – the (presumed) model of autonomous, self-made womanhood she is not, and imagines she might like to be.

Madeleine lives up to expectations from the second she arrives in the driveway doling out double-cheek kisses, and Ashley gloms on, plying her with a barrage of questions and compliments. Eager to make a good impression, Madeleine handles the attention well. She indulges Ashley’s exuberance, forgives Johnny’s antagonism, and does her best to smooth over Peg’s suspicion.

There’s a fine, observant comedy in this meeting of sensibilities, a Jamesian alertness to irony, nuance, and the precise texture of interweaving social codes. You sense Madeleine’s fascination at her first real contact with a way of life she previously knew through books and art, and notice the ways she instinctively overcompensates, intellectualizes, and asserts her ego.

Mr. Morrison is even more adept at illustrating the family’s oscillation between curiosity and distrust, empathy and envy. “Junebug” plays variations on these feelings as it slowly builds to a dramatic and symbolic crisis: Ashley goes into labor at the exact moment when Madeleine has one last chance to secure representation for her artist. A choice must be made, a side must be taken: the self or the group, business or family, art or life.

“Junebug” rides this schematic straight into the contemporary American divide. It doesn’t presume to smooth over our irreconcilable differences; it tries to humanize them. That’s a worthy impulse in these divisive times, a laudable change of pace from the mannered, solipsistic whimsy endemic to American independent cinema.

Working from a script by playwright Angus MacLachlan, Mr. Morrison and his cast excel in their creation of a Southern clan stripped of sentimentality. Their solidarity is genuine – and genuinely admirable – but it is also a source of unhappiness. You sense both the strength and the suffocating weight of the nuclear family; the sustenance it provides and the limitations it imposes.

A friend of mine who grew up in North Carolina exalts this aspect of the film as a rare expression of the Southern ethos from the inside out. I’m sure he’s right: The family portrait feels authentic, lived-in. But as we talked over the film from our different points of view – a dialogue that “Junebug” productively elicits – my objections to certain dramatic failures were dismissed on the grounds that, having never lived in a red state, I simply couldn’t “get it.”

That polite conversation among friends should devolve into the same polarization the movie seeks to diffuse may be an ironic affirmation of its potency. And it points to a tangle at the heart of a movie that otherwise loosens some national knots. But it also points to what I take as its central flaw: an imbalance of perspective.

Through the family on one side and Madeleine on the other, “Junebug” offers two different conduits of sympathy. In the most controlled passages of the film, when these opposing viewpoints are held in equipoise, balance is achieved and both sides are illuminated.

Once the third act plot mechanics gear up, however, the rich ambivalence of the former is compromised by the faulty characterization of the latter. Madeleine offers a surrogate for the urban art-house audience – me and you and almost everyone we know – but she ends up an ineffectual one. Casting her as a dealer in outsider art is much too neat, a screenplay contrivance that ultimately reinforces the cultural stagnation it attempts to relieve. The vitality of “Junebug” is strong enough to withstand her, but it doesn’t really need her. And that may be part of the point.