As Leena, the conniving slut of Romulus Linney's Appalachian-set "Unchanging Love" at the Studio Theatre, Robin Baxter is evil, evil, evil -- she likes sex and she likes money, plus she's barren, an adulteress and very probably not a natural blonde. A person can't hardly get more awful, especially not a female-type person, which Leena, turning her wiles on man after man, definitely is. This pile of Spider Woman cliches can't really be called a character, but Baxter brings a full-bodied sensuality and cool, amoral strength to the part. Playing a woman who's married into the wealthy Pitman clan with only her financial expertise as a dowry, she's full of grasping, greedy life. As the play progresses, you begin to feel that the wan, virtuous characters who are her victims deserve to fall to her.

Linney based his play on a Chekhov short story, but his dramaturgy is a marriage of Arthur Miller -- lots of big confrontational speeches -- and Lillian Hellman -- lots of nasty scheming white people. Owing to colorblind casting that ignores the race prejudice that existed in the Prohibition-era South, there is an unsympathetic black character too: Elmer Musgrove, the poor farmer who trades his fertile daughter to the money-rich, children-poor Pitmans in return for four acres of near-worthless land. Equal-opportunity venality.

The Pitmans, who own the only store in the impoverished town of Maynard, N.C., use their economic power to cheat their customers. They're Linney's version of the little foxes that spoil the vines. Here, as with Lillian Hellman, evil abides in the rich and reaches the poor only as a result of trickle-down morality. "If the store didn't cheat so much," cries the Pitman patriarch's softhearted wife, Barbara, "they wouldn't cheat so much!" -- "they" being the poor, whose innate virtue is corrupted by the nasty capitalists who run their lives.

To do him justice, Linney doesn't get rapturous about the scenic beauties and homely ways that accompany rural poverty. But his social attitudes can be confusing. Leena is plotting to build a brick factory on land she helped the Pitmans acquire. This is presented as an act of rank villainy, but it's never explained why bringing factory jobs into a depressed area would be so bad for the locals. But then, except for the corrupt Musgroves and their innocent daughter, the poor don't appear in the play. The guilt-ridden rich -- "This town is mad at us! It wants to lay bloody hands on us!" -- speak for them.

"Unchanging Love" takes place in a morally uncomplicated world. Characters are either good, bad or weak, which ends up being the same as bad. With such simple psychology at work, the play inevitably becomes a melodrama. Linney's affection for Southern mountain culture (he grew up in Boone, N.C.) leads him to include a number of regional hymns, songs and social practices, such as a joke-telling session-competition among the men. The result, under Edward Morgan's direction, is that "Unchanging Love" is a melodrama that occasionally stops in its tracks for lyrical and folk interludes.

What with all the skulking and speechifying they have to do, the actors generally succeed not by acting but by injecting their characters with general, easily recognizable qualities. Constance Fowlkes as Barbara and Carla Hargrove as the child-bride Judy both exude a deep sweetness. Bill Grimmette is all servile anxiety as Musgrove, and as the villainous Lawyer Crutch Holston, Carter Jahncke is so oily he's just this side of grease. As Avery, the weak Pitman son, Peter Mackenzie is soft and pitiful. Janey Richards does more complex work in her small role as Mrs. Musgrove, sketching chillingly the picture of a woman who knows her place and intends to stay in it. And then there's Baxter, striding her vulgar, unrepentant way into the pantheon -- Scarlett, Blanche, Regina -- of Great Southern Bitches. She isn't what the play means for us to find attractive, but her selfish vitality has more life in it than any of the virtues that glimmer weakly around her. She's a missionary for pure meanness.

Unchanging Love, by Romulus Linney. Directed by Edward Morgan. Sets, James Kronzer; lighting, David R. Zemmels; costumes, Helen Q. Huang; music direction, Edward Morgan. With Bill Grimmette, Janey Richards, Carla Hargrove, Churchill Clark, Constance Fowlkes, Peter Mackenzie, Robin Baxter, Jason Adams, Carter Jahncke, Hugh Nees. At the Studio Theatre, 1333 P St. NW, through Feb. 3.