Conviction, a word that connotes both the condemnation of a criminal as well as the passionate fervor by which one defends a belief or principle.  Combine the two and you get “Conviction,” starring Sam Rockwell and Hillary Swank. The film is based on the true story of Kenny Waters (Rockwell), who was sentenced to life in prison for a crime he didn’t commit, and his sister Betty Anne (Swank) who subsequently dedicated her life to fighting for his release. Featuring a star-studded cast and a gripping true-life narrative, “Conviction” seems a recipe for box office and award-season success, yet the film veers disappointingly into overly sensational moralizing which frequently trivializes its source material.

With her brother in jail for robbery and murder, the stakes are high for Betty Anne to clear his name.  A high school dropout at the time of Kenny’s conviction, for the sake of her brother, she manages to obtain a GED, a bachelor’s, a master’s in education, and ultimately a law degree. Word of a single mother raising two boys while working part-time and putting herself through law school eventually leads to the enlistment of Barry Scheck, founder of the Innocence Project. The Innocence Project is a non-profit organization that works to exonerate wrongfully convicted individuals through DNA testing which played a large role in helping to achieve Waters’s acquittal.

Beyond the scope of simply telling Kenny and Betty Anne’s account, “Conviction” is also largely the story of both the Innocence Project and the greater struggle of working within a sometimes-flawed system of justice. Sometimes subtly done, mostly this approaches pedagogical moralizing: “You know your father’d be dead right now if Massachusetts had the death penalty,” Betty Anne tells Kenny’s daughter.

Perhaps as a result of the film’s desire to turn Kenny’s story into a moral lesson it simplifies the nuances and complexity. For example, the trial scene almost completely glosses over the specifics of Kenny’s involvement in the crime. From what is actually depicted in the movie it seems that Kenny was convicted on an extremely circumstantial basis—that is, a couple witnesses claiming to have heard Kenny admit to the crime and his blood type matching that of the perpetrator. The only real explanation for how he ended up wrongly charged of murder and robbery is that he didn’t bother to hire a more expensive and more qualified lawyer than the public defender because he was certain of his innocence.

Similarly, the film has a simplistic style so that all involved can focus on the plot. Director Tony Goldwyn engages in an occasional artsy camera angle but the film’s cinematography is underemphasized. Construction of the scenes is fairly straightforward and thus better attests to the weight of the narrative. However, the problem with “Conviction” arises when the arresting (no pun intended) account repeatedly devolves into mere theatrical melodrama.

Nowhere is this more evident than in Hillary Swank’s acting. A two-time Academy award-winning actress, Swank seems to have a natural predilection for heart-wrenching roles where she plays an underdog protagonist who ends up on top only through her hard work and perseverance. That may have worked for her in “Boys Don’t Cry” and “Million Dollar Baby”—nonetheless it not only falls completely short for her in “Conviction,” but also comes off as picturesque peddling to a sympathetic audience.

Swank’s acting may be fairly exaggerated but to her credit this may be due in part to the enormously overdramatic script. While visiting with brother Kenny in jail, Swank pleads, “You just have to promise me that you’ll never give up!” The script is pockmarked with clichés and perhaps bears most of the blame for Swank’s over-the-top performance.

Yet, while much of “Conviction” is overdone, not all of the performances are quite as bad as Swank’s. Sam Rockwell is very effective in his role as Kenny Waters, a character whose ethics are deliberately ambiguous. For though Betty Anne is certain of his innocence, Rockwell is able to convey the fine line Kenny walked between being a good person at heart yet also prone to violence. Minnie Driver, who serves as an ironic foil for Swank’s character, also adds a degree of realism to the film.

The writing isn’t always sensationalized, though, and sometimes manages to maintain an element of humor that balances out some of the intensity evident in other parts of the scripts. Betty Anne’s son, who fixes up a place for Kenny to live upon his expected release, exemplifies this when he says, “At least Uncle Kenny’ll  think it’s nice…compared to jail.”

“Conviction” is entertaining and funny but very much a production. Understandably, the film ends on the happy note of the case of Kenny Waters finally brought to justice, but chooses to omit the fact that he passed away only six months later after spending nearly a third of his life in prison for a crime of which he was innocent.  Between its didactic aspect and its tweaking of the truth, “Conviction” is definitely a missed opportunity.