Starring Kimberly Elise, Shemar Moore, and Steve Harris. Rated PG.

Although this movie is being promoted as yet another over-the-top African-American comedy, it is considerably more than that, in both a positive and a negative sense. Indeed, Diary of a Mad Black Woman is so in tune with 21st-century U.S. mythology, its script could probably be successfully transformed into a high-school civics test.

First, the story. After 18 years of marriage, nouveau riche ghetto bride Helen McCarter (Kimberly Elise) is given the boot by her high-powered lawyer husband Charles (The Practice's Steve Harris, whose super-blunt approach makes assholery appear virtually indistinguishable from the self-righteousness he used to demonstrate every Sunday on TV). After literally picking her ass up off her former front doorstep, Helen is forced to seek refuge in Grandmother Madea's house, the part of this larger-than-life matriarch being assumed by screenwriter Tyler Perry (who also plays two characters who are NOT in drag). To the prodigal granddaughter's surprise, her old life seems to agree with her-especially the churchgoing part-and she soon meets a light-skinned man who is as perfect as her ex-husband was defective. (Indeed, Shemar Moore sometimes comes across like a Dan Hill song made flesh.)

Before she can surrender to her new love, though, she must first make peace with her past, to divorce the loathsome Charles in her heart as well as on paper.

Here's where things get tricky. The ideology being preached by this film is as conservative as any found in a charismatic revival show, and its emphasis on the values of family, hard work, monogamy, and religion utterly relentless. Of course, one could say that what Perry is doing in both his play and movie is no different from what Chris Rock does on-stage: holding up a traditional ideal to viewers whose lives have been blighted by too little consistency and too much abandonment, delivering each sermon in a manner that combines humour and hope.

What this means, basically, is that Diary of a Mad Black Woman will seem liberating to some people and imprisoning to others. At one and the same time, it is both a get-out-of-jail-free card and another nail in an already airless coffin.

Most surprisingly of all, Diary of a Mad Black Woman will probably prove equally moving to both groups.

Only in America.