Is it really possible to make a comedy about abortion? Alexander Payne, who cowrote and directed this mischievous bit of sociological screwball, has brought it off. And he has done it by creating a heroine so degraded, so memorably vile, that she throws us off our usual track of empathy. In Omaha, Ruth Stoops (Laura Dern), a dirty gutter wretch, hustles for a few dollars so she can get high on aerosol fumes; that’s her entire life. Arrested for vagrancy, and pregnant for the fifth time, this skanky addict-loser is taken in by Norman and Gail Stoney (Kurtwood Smith and Mary Kay Place), beaming local leaders of a Christian anti-abortion organization called the Baby Savers. At first, the film looks like a cheap shot at pro-life piety. But when Ruth is stolen by a pair of lesbian pro-choice activists, the satirical framework clicks into place. Citizen Ruth scabrously sends up a war in which both sides have become so consumed by righteous zealotry that they’ve lost touch with the individual women they’re ostensibly out to save. The movie is a little too aware of its own outrageousness, but the performances are pinpoint perfect: Mary Kay Place, hatefully sunny; Swoosie Kurtz, the cut-and-dried soul of leftist smugness; and Burt Reynolds, in top oily form as the Baby Savers’ evangelical leader. And Dern is a revelation: Desperate, kooky, as devious as a pack rat, her Ruth grows likable, and even heroic, by remaining too pure a scoundrel to be taken in by the phonies around her.