No other recent film has demonstrated the extent to which modern-day studio melodramas have descended to the level of old television movies better than “Domestic Disturbance.” The Harold Becker thriller features a major star and has been mounted with great care and obvious expense, but the narrative–about a divorced father’s determination to protect his son against his potentially malevolent stepfather–would barely have made a decent Movie-of-the-Week twenty years ago. When your mind wanders during the picture–and given its mediocrity, there’s plenty of opportunity for that to happen–you can imagine precisely the same story being told back in 1985 or so on a flickering small screen with somebody like Bruce Boxleitner or Peter Strauss in the lead. It’s a depressing thought. Even the title is generic.

The plot of the picture is extremely simple. John Travolta plays Frank Morrison, a divorced boat-builder whose ex-wife Susan (Teri Polo) is remarrying wealthy, well-liked businessman Rick Barnes (Vince Vaughn). Frank remains very close to his son Danny (Matt O’Leary), who’s begun acting out as a result of his parents’ break-up, and, amiable fellow that he is, tries to persuade the boy to give Barnes a chance. After the wedding, however, Danny alleges that he witnessed Rick kill someone. (Shades of William Castle’s 1965 “I Saw What You Did.”) Though the kid recants under threat from Barnes, Frank remains convinced that the story is true, believing that the victim was Ray Coleman (Steve Buscemi), an odd character who’d shown up at the nuptials and stayed around afterward. After the police dismiss his suspicions, he investigates on his own, eventually putting himself in danger by looking into Rick’s past. The conclusion, needless to say, brings jeopardy to the entire original-family unit.

There’s a great deal that’s wrong with “Domestic Disturbance.” Most basic is the endangered child premise, which would be unattractive even if it were handed with any subtlety, as is not the case here. But the problem is exacerbated by a lack of shading in the characters and dumb narrative turns. Father Frank, for instance, is just your basic dour, concerned parent, and Rick little more than a snarling cartoon. Susan, meanwhile, is totally clueless until the very end, and Ray a standard-issue sleazebag. Danny is the most interesting figure, but he’s treated pretty much as a mere plot device. Under these circumstances it’s predictable that the actors aren’t at their best. Travolta does his serious regular-guy routine, the same sort of thing he essayed in “White Man’s Burden” and “Mad City” without much success. (He’s really better in showier parts.) Vaughn displays a sinister smile which looks good, especially in shadow, but not much else. Polo’s a cipher, and Buscemi does little more than his usual shtick. O’Leary shows promise, but it will take a better role than this to fulfill it.

As to the script, its weaknesses are legion. Apart from the fact that the wife is portrayed as totally oblivious to what’s happening around her, the local cops are necessarily depicted as either fools or incompetents. Frank ultimately discovers the truth about Rick’s past with absurd ease by simply clicking onto a newspaper internet site. And out of nowhere appears a blast furnace to provide a convenient means by which a body can be incinerated. The protracted finale is a further mistake–it’s messy, ugly and ultimately absurd–and it’s made worse by Becker’s clumsy staging: the big confrontation is conducted in so confined a space, and is so poorly lit and shot (by Michael Seresin), that it’s almost impossible to see what’s happening to whom, let alone care about the outcome. A bland score by Mike Mancina fails to pump things up.

A wicked stepfather is surely a good subject for a movie. Joe Ruben showed just how good back in 1987, when he made his nifty little chiller “The Stepfather,” featuring a sharp script by Donald E. Westlake, skillful direction by Ruben and an extravagantly vivid turn from Terry O’Quinn. It also properly focused on the relationship between the child and the step-parent, in the process making the daughter, in its case, a far stronger and less dependent character than Danny is here. “Domestic Disturbance” may have a much bigger star and a glossier production, but it’s not in the same class.