The lack of an article, definite or not, in the title of Jake Scott’s film suggests that Brad Ingelsby’s screenplay might be intended to have some universal import. If so, it must be his belief that the lives of most American women represent a kind of mini-series soap opera slimmed down to a two-hour compilation of dramatic (or melodramatic) highlights. “American Woman” is actually just the tale of a particular woman who endures a succession of travails before, apparently, accepting her life as it is rather than as she might like it to be.

She’s Deb Callahan (Sienna Miller), who’s introduced as a thirtysomething single mother dolling herself up for another date in her small Pennsylvania town. Still attractive but brassy and abrasive, she works as a supermarket cashier while carrying on an affair with a married man. Living with her is her teen daughter Bridget (Sky Ferreira), who has a child, Jesse, with a scruffy boy named Tyler (Ale Neustaedter) with whom the girl is continuing an on-and-off relationship.

One night Bridget goes off on a date with Tyler and doesn’t come home. Deb is furious, not so much out of concern for Bridget but because she’s been stuck babysitting, and confronts Tyler, who claims that he’d dropped her off at a girlfriend’s after an argument. As Bridget’s absence is prolonged, her accusations against him grow increasingly pointed, though a sympathetic cop (E. Roger Mitchell) points out that there is no evidence against him.

Distraught, and despite the support she gets from family—her mother (Amy Ryan), sister (Christina Hendricks) and brother-in-law (Will Sasso), support that, of course, she finds more intrusive and irritating than helpful—she gets drunk and crashes her car.

She survives, and six years later is raising her grandson (Aidan McGraw) on her own. Unfortunately, she has linked up with Ray (Pat Healy), an abusive control freak who bullies Jesse to boot. It takes a while for Deb finally to break up with him. Happily she meets a much nicer guy named Chris (Aaron Paul) and, after a while, they get married. He even becomes a true father figure to Jesse (now Aidan Fiske), a gangly teen. In another unfortunate turn, however, he turns out to be much less the perfect catch than he seems.

The film comes full circle at the close, with the truth about Bridget’s disappearance finally coming out. It leads to a catharsis for Deb, who by this time has, despite all the obstacles, earned a degree and can begin a new chapter in her life with Jesse.

One can point to elements of “American Women” that are intermittently affecting. Scenes in which Deb reconnects, years after the disappearance, with Tyler and they inch toward a reconciliation for Jesse’s sake, or she suddenly switches from anger to affection as she interacts with her sister and mother, are nicely written and played well. It will be pretty much impossible, moreover, for a viewer to remain unmoved when Deb and Jesse have to deal with the revelation of what happened to Bridget.

Much of the film, however, has a melodramatic feel, despite the efforts of the cast and Scott to keep it grounded in reality. Much of that has to do with Miller’s performance. She throws herself into the role with undoubted commitment—perhaps a bit too much in some of the more emotional scenes, especially early on. Nor does she age convincingly over the span of some fifteen years. (Few of the adults do, frankly, except for Madigan, though Jesse does.) Hendricks and Sasso are fine nonetheless, and Neustadter does well by his limited opportunities, though Healy comes on awfully strong as the caddish Ray. The technical credits are fine across the board, though this is obviously a picture made on a very modest budget.

As a portrait of a woman’s struggle against the manifold obstacles life can send her way, Scott’s film carries some sporadic power. Overall, however, it’s a disappointment.