It may be titled “Marriage Story,” but Noah Baumbach’s film—his best—is actually a tale of divorce, which is, of course, increasingly a part of marriage, and doesn’t completely end a relationship, especially when children are involved.  It’s a bracing. thoughtful examination of how a couple’s intention to separate as amicably as possible for the sake of the son they both love gradually turns into legal and emotional warfare before the conflict subsides.  Featuring a host of superb performances headed by Scarlett Johansson and Adam Driver as the feuding spouses, it bristles with energy and emotion ranging from darkly amusing to brutally unkind.

Driver and Johansson are Charlie and Nicole Barber, a couple with a sweet eight-year old son, Henry (Azhy Robertson).  Charlie is the artistic director of a small but well-regarded experimental theatrical company in New York City, and Nicole is its star, having joined after an appearance in a sexy teen movie and earned plaudits in serious roles like her current take on “Electra.”  To top it all off, Charlie has just been informed that he’s to receive a MacArthur “Genius” grant. 

But all is not well in the ostensibly happy family.  Though the film begins with each spouse reading a personal statement about what he or she admires about the other, it turns out that the exercise is part of a marriage mediation session that quickly goes awry when Nicole abruptly breaks it off.  Later we see her informing Charlie, with the help of her flaky mother Sandra (Julie Hagerty) and sister Cassie (Merritt Wever), of her decision to seek a divorce when he comes to visit her and Henry in her hometown of Los Angeles, where she’s gone to film a pilot for a TV series.

Charlie is flummoxed by the news, even if he has been having an affair with a member of his theatre company, and Nicole knows it.  But he’s especially surprised by Nicole’s determination to stay in L.A., which will inevitably affect his contact with his son.  Though they informally agree to handle the separation as simply as possible, when Nicole consults Nora Fanshaw (Laura Dern, in a dynamite performance), a take-no-prisoners divorce lawyer, her deepest feelings about having played second fiddle to Charlie’s priorities over the years crystallize, and when his response—hiring a likable but laid-back attorney named Bert Spitz (a droll Alan Alda) to represent him—proves no contest, he replaces him with a shark named Jay Marotta (Ray Liotta, also dynamic), and the courtroom arguments take on a lethal tone.

“Marriage Story” unfolds with a back-and-forth rhythm, shifting points of view between Nicole and Charlie, but perhaps inevitably, given the fact that it was written and directed by a man (who, in addition, has said that his own experience of divorce is reflected in the script), it skews, at least in terms of running-time, to Charlie’s side.  There’s an extended sequence, for example, in which he’s compelled to endure a visit from a court-appointed evaluator (Martha Kelly) who solemnly observes him and Henry in the L.A. apartment he’s rented for the duration of the proceedings.  A grimly funny bit of business with a knife ends the evening.

That doesn’t mean, however, that Charlie’s portrayed simply as a victim.  Certainly he earns our sympathy when Henry shows reluctance to spend time with him—especially in a sequence of trick-or-treating gone bad.  But as the film progresses his nonchalant assumptions about how things should be in his marriage are revealed, along with his obliviousness to the effect they’ve had on Nicole’s aspirations.  Their increasingly acrimonious interaction comes to a peak in a heated exchange in Charlie’s apartment, in which both angrily vent their frustrations but ultimately reach a modicum of mutual understanding.  And wonder of wonders, Baumbach manages to close his film about an increasingly nasty divorce battle on a note which isn’t exactly happy, but suggests that a breakup needn’t mean endless animosity. 

Driver and Johansson do exceptional work here, and both will undoubtedly be in the running as awards season rolls around.  Her work may be cooler and his more heated, but their approaches dovetail beautifully, disclosing differences in the characters that help explain the inevitability of their breakup in ways they probably couldn’t articulate.  The supporting players—including young Robertson—are uniformly superb (Wallace Shawn delivers a hilarious cameo as a garrulous member of Charlie’s troupe who can’t stop reminiscing about the good old days), and the technical side—Jade Healy’s production design, Mark Bridges’ costumes, Robbie Ryan’s cinematography, Jennifer Lame’s editing—is impeccable.

Randy Newman composed the score for “Marriage Story,” and it’s a good one.  But the musical heart of the film really consists of two songs from Stephen Sondheim’s “Company” used to represent the attitudes of the Barbers.  At one point Nicole, Sandra and Cassie perform “You Could Drive a Person Crazy,” and toward the close Driver takes to the stage at a club to sing “Being Alive.”  Just as in Sondheim’s edgy musical, the numbers reflect the harsh realities of commitment, which is what, in the end, Baumbach’s film is all about.  Employing them as he does here may be a little too New York chic for comfort, but it works.  As does this potent, incisive film.