What could have possessed them?

The forces of good and evil wage a holier than thou battle for our attention in the hybrid thriller “The Exorcism of Emily Rose.” Inserting a dose of horror into a standard courtroom drama, writer-director Scott Derrickson and co-writer Paul Harris Boardman have constructed a well-cast yet dopey tale that is much less than the sum of its parts. It’s certainly creepy, but not always in ways the filmmakers intended.

Laura Linney stars as Erin Bruner, a high-profile defense attorney hired by a Catholic archdiocese to defend Father Moore (Tom Wikinson), a priest accused of negligent homicide. The church, understandably not wanting to appear medieval, would prefer to make the case go away by having Moore plead out to the charge that the exorcism he performed on 19-year-old Emily Rose (Jennifer Carpenter) led to the college freshman’s death.

Going against the wishes of the archdiocese and her boss (Colm Feore), however, Bruner not only takes the case to trial but allows Moore to testify. The priest’s passionate desire to tell Emily’s story and a malfunctioning alarm clock are about all it takes to convince the attorney, an avowed agnostic, that it’s a case worth the risk to her career.

The audience witnesses the exorcism through the testimonies of Moore, Emily’s father (Andrew Wheeler) and her college friend, Jason (Joshua Close). The flashbacks show to good effect the work of production designer David Brisbin, whose chilled to the bone landscape and sparse farmhouse are the setting for Emily’s exorcism, and the frosty cinematography of Tom Stern.

Derrickson acknowledges a fondness for Kurosawa, “Rashomon” in particular, but rather than giving conflicting accounts of Emily’s ordeal, the flashbacks all mesh. Carpenter gamely contorts her voice and body to convey the demonic possession (or is it epilepsy compounded by psychosis, as Campbell Scott’s prosecutor argues?), but the film’s frights come mainly through shock cuts and sound amplification (muted to PG-13-acceptable levels).

Any suspense built through the exorcism exits the movie whenever the action shifts back to the courtroom. It does not help the audience suspend disbelief to have Scott’s Ethan Thomas, a churchgoing but highly rational Methodist, provide plausible scientific and medical explanations at every turn. It’s the equivalent of a Superman movie continually calling attention to the fact that the Man of Steel can’t actually fly. When Thomas objects to one of Bruner’s witnesses on the grounds of silliness, you will have to stifle the urge to second the motion.

The film is also a victim of its own structure in the sense that there is no mystery to the narrative. The final rendering of the jury’s verdict is anticlimactic to what’s come before -- not that there’s anything terribly dramatic in the buildup. It’s just that there’s no question concerning Emily’s fate, and the way the filmmakers spin the story, it all comes down to embracing superstition by doubting reason. That Bruner is so easily swayed makes you wonder how she became an attorney in the first place. Audience sympathy will fall squarely on one side of the courtroom or the other based on their preexisting beliefs, and nothing in the film will change that.

*

‘The Exorcism of Emily Rose’

MPAA rating: PG-13 for thematic material, including intense/ frightening sequences and disturbing images

Times guidelines: Routine theatrics of possession

A Screen Gems presentation, released by Sony Pictures. Director Scott Derrickson. Producers Tom Rosenberg, Gary Lucchesi, Paul Harris Boardman, Tripp Vinson, Beau Flynn. Executive producers Andre Lamal, Terry McKay, David McIlvain, Julie Yorn. Screenplay by Paul Harris Boardman & Scott Derrickson. Director of photography Tom Stern. Editor Jeff Betancourt. Costume designer Tish Monaghan. Music Christopher Young. Production designer David Brisban. Running time: 1 hour, 54 minutes.

In general release.