Because of its controversial subject matter, Marc Forster’s “Monster’s Ball” has the potential to spark an extreme, politicized reaction. Confronted with racism, suicide, sex, violence, and execution, the audience wants nothing more than an outlet for its emotions — something to cry about or scream at.

But Forster’s film is also a strict exercise in subtlety. Despite dealing with issues that lend themselves to political messages and morals, Forster’s approach is understated. The suppression of an emotional response seems to be Forster’s goal, and through this suppression comes his greatest achievement: showcasing sheer talent and beauty.

“Monster’s Ball” focuses on the strange lives of the Grotowski family — three men spanning three generations — and their respective collisions with racism, sex, and death. The family trade is an unusual one, executing prisoners at the local state penitentiary. After losing his stomach before an execution, the youngest Grotowski, Sonny (Heath Ledger with a convincing Southern accent) kills himself, understanding that he has betrayed the family by not fulfilling his job.

Sonny’s death brings a gradual, tempered change in his father, Hank (Billy Bob Thornton). After retiring from the prison, Hank begins to heal, only to confront the death of another child. This time, it is the son of Leticia Musgrove (Halle Berry). As Hank begins an affair with the grief-stricken Leticia, he discovers that he executed her husband Lawrence (the mostly believable Sean “P. Diddy” Combs) weeks earlier, when Sonny lost his nerve.

To contrast with the change that slowly overcomes Hank, Forster creates a world in which life and death are commonplace and unimportant. Emotionless sex — an act that normally represents togetherness and vitality — takes place fast and dully in poorly lit apartments. Death is equally unglamorous. Nobody, particularly not the executioners, thinks twice about the execution of Lawrence. There is none of the glaring symbolism and sickliness of “Dancer in the Dark,” for example.

Instead, Forster uses a quietly effective technique, as when he switches between Leticia brushing her teeth and Lawrence burning with electricity. He leaves out suggestions of otherworldly, telepathic unity between husband and wife, instead showing them as they are in their separate worlds — a powerful observation.

Indeed, the most poignant element in the film’s dull world is the solitude of its inhabitants. “Monster’s Ball” is a movie of few characters, and none of those characters ever really breaks out of his or her shell. Forster captures this separation, allowing himself to dwell on the symbolism of jail bars and reflecting glass that literally divide these solitary creatures.

Fortunately, this symbolism never becomes too obvious or over the top, and subtlety still rules the film. These moments of solitude let cinematographer Roberto Schaefer focus on the beauty of landscapes and their seeming permanence relative to humans. Forster also heightens sound, giving the film the whispery texture of an old record and a sense of history. It seems that time passes so quickly that the characters have stopped trying to grasp moments and have instead let go, letting life and its varied emotions pass them by.

Since they have relinquished loud, extreme emotions, the ensemble cast of “Monster’s Ball” must rely on nuance, and the actors pull it off wonderfully. Thornton gets deep into his character, comfortable and thorough despite his muted emotions. Berry’s performance is equally notable. In one powerful if disturbing scene Berry moves, within seconds, from nostalgic laughter to deep grief to sexual longing, all with subtle changes of gesture and voice.

Among the supporting cast, Peter Boyle pulls off the stubborn sorrow of a dying patriarch. His racist character, once a strong, hate-and-lust-filled man, now breathes with a respirator and feels intense if silent self-loathing. And in a role originally slated to be played by “American Beauty’s” Wes Bentley, Ledger pulls off his deepest character to date.

When Forster finally unites the two tragic figures of Hank and Leticia, the change is palpable. In post-coital glow, Hank even comments, “I haven’t felt anything in so long.” The film has more emotion after this point. Hank begins to overcome his own racism, while Leticia reacts loudly to his father’s. Finally, there are moments of intimacy — characters and their passions finally overpower the whispery sound and stretching landscapes.

Forster thankfully saves “Monster’s Ball” from becoming a tale of metamorphosis: the change itself is slight and sequential instead of sudden and overpowering. While the film may lose some potential impact because of its overarching silence, it ultimately benefits from the preserved subtlety of its performances and writing, a welcome change of pace from Hollywood’s love of spectacle.