Dead Man Walking.

THE death penalty remains one of the trickier problems we find ourselves grappling with. Is taking a life for a life justice or barbarism? Is the state entitled to turn killer under any circumstances? Is the Old Testament "a tooth for a tooth" just? Or is some modified form of the New Testament's not casting stones more appropriate? And then the economics of it. What costs the taxpayer more: the death penalty with all those appeals and stays of execution, or extensive imprisonment and maintenance of the prisoners? And what about the risk of recidivism -- those news stories about parolees promptly raping and murdering again?

I confess I don't know where I stand on all this. Which is partly why I am the proper audience for a movie such as Dead Man Walking, and perhaps why I find it so absorbing. It is based on the homonymous book by Sister Helen Prejean, a nun whose ministry to the men on Death Row has turned her into a leading advocate for the abolition of capital punishment. Her book is based principally, I gather, on two of the killers she dealt with: one repentant and anxious, the other sullen and unfeeling. Tim Robbins, the actor who adapted the book and directed the film, fused the two men into one, Matthew Poncelet, creating a more interestingly complex character. It was certainly a clever move to have the guiltier of the two accomplices -- the one who remains unseen -- get off with a lighter sentence, whereas Poncelet, who merely came along for the ride and was sucked into the rape of a young woman and the murder of her and her fiance, is condemned to death.

The movie's chief virtue is its genuine striving to be fair to all concerned. This is particularly apparent in the treatment of the crime. Verbal and pictorial references to it weave their way in increasing detail throughout the film. The rape has erotic aspects, but is not wallowed in; its viciousness, and that of the killings, is strongly but unexploitatively conveyed. The final punishment is crosscut with the crime, so that sympathy for the by now greatly humanized Poncelet is not allowed to outweigh our horror at what he did. The film is like one of those Platonic dialogues ending in the well-known Socratic aporia: nothing is spelled out; the viewer's mind must clear its own way through ironies and ambiguities.

Since Susan Sarandon, who plays Sister Helen, and Tim Robbins are life partners jointly active in liberal causes, we can extrapolate their stand against capital punishment. And careful scrutiny of the film suggests this position, albeit without shortchanging the contrary arguments. This balance is achieved largely through the attention paid to the parents of the victims (though the murderer's dysfunctional family is likewise cogently examined), and also through showing the contradictory goings-on both inside and outside Louisiana's Angola prison, and various other actual locations where much of the film was shot.

Helen Prejean also prayed and shared grief with the victims' families, even though it was hard to overcome their resistance to one whom they viewed as an ally of the guilty. The three parents in question neatly -- but not too neatly -- represent three points of view: realization that an execution might not be the best solution, insistence on a life for a life, and a transitional attitude in between. The three roles are superbly filled by Raymond J. Barry, Celia Weston, and R. Lee Ermey. None of these actors is overfamiliar to moviegoers, which greatly heightens the quasi-documentary atmosphere. But even the stars in the two leads manage admirably to make you forget who they are.

Miss Sarandon has evolved over the years from sexy starlet, through seductive leading lady, to mature and magnificent actress for all occasions, emphasis having shifted from her commanding bosom to her enormous, eloquent eyes -- two globes containing continents of compassion. She has that priceless reverse-baked-Alaska ability of being cool of face and voice while conveying fervor within, yet staying scrupulously within the bounds of histrionic seemliness. There are things about nuns I have hitherto never fully understood; this actress, given this script, makes them lucently clear.

As Poncelet, Sean Penn is a revelation. Latterly a highly questionable writer-director, Penn has all along been a compelling actor. Here he is nothing short of stunning. Every physical detail of his characterization -- looks, expressions, bearing, gestures, intonation, silences -- is better than just correct: correct and unpredictable. There is also a nascent spiritual quality, growth of the soul, that the performance makes manifest. And there is no cheap plea for sympathy, only a certain flamboyance of the apposite kind: part Byronic, part defiantly aggressive, part pitiful. In short, a histrionic landmark.

Fascinating, too, are the performances by Roberta Maxwell as Poncelet's weirdly erratic yet not inhuman mother, and Lois Smith as an unidealized, idiomatic mother to Sister Helen -- herself, needless to say, no unerring plaster saint. Even the smallest parts are accorded a flavorous authenticity, and Roger Deakins's camera is enlightenedly ironic as it traces inextricable moral entanglements with a worldly-wise, pictorially sensitive gaze. I am told on good authority that the film's initial three-hour version was by far the best; the reduction by half an hour, second-best; and the final cut demanded by the producers, two hours plus, only third-best. A sad comment on our times, when trash like Heat can go on for three hours, but Dead Man Walking must be severely curtailed.

Even so, plenty is left to be thankful for. Especially the realization fostered here that questions exist to which there are no cut-and-dried answers, questions that must always be addressed afresh, and wrestled with for solutions that are, at best, provisional.