LOVE TRIANGLE: Drew DeCaro (foreground) Julie Rowe and Kevin Bergen in Harold Pinter's Betrayal, now playing at American Stage. Credit: Courtesy American Stage

LOVE TRIANGLE: Drew DeCaro (foreground) Julie Rowe and Kevin Bergen in Harold Pinter’s Betrayal, now playing at American Stage. Credit: Courtesy American Stage

The real subject matter of Harold Pinter's greatest plays has always remained mysterious. Who are the two men who haze and hound a third in The Birthday Party? What is the secret significance of the ill-tempered vagrant whom two brothers introduce into their flat in The Caretaker? Why does a woman, married to a professor, decide to become his evil family's live-in whore in The Homecoming?

In these and in a few other plays — including The Dumb Waiter and Old Times — Pinter distinguished himself as a man who knew something, something deep and unsavory, about the forces at work in human society. Exactly what these forces were and how they operated was never entirely clear. But Pinter, at the very least, had taken a photograph. If you could make sense of the blurred figures, you might just understand something tremendous.

The Birthday Party reached the stage in 1957 and Old Times was produced in 1970; the plays that followed mostly didn't have the same weight. Certainly Betrayal (1978) — which is currently being shown in a mildly interesting version at American Stage — comes across today as Pinter Lite. All the mystery and menace that make Pinter Pinter are missing from the play, and what we're offered instead is a largely superficial adultery drama with one special feature only: It's told backward, from last scene to first.

If the American Stage actors were more adroit at speaking Pinter's language — and crafting his pauses — the play still might be a success. But only one, Julie Rowe, finds all the opportunities in her dialogue, while Kevin Bergen makes do with the obvious only, and Drew DeCaro offers less than that. So if you were hoping that Betrayal might explain Pinter's Nobel Prize, you're in for a letdown. Try the author's earlier plays if you want to know why he matters.

If Betrayal's story were told first to last, it would go something like this: Jerry is a literary agent whose best friend, Robert, a publisher, is married to Emma. One day Jerry tells Emma that he's wildly in love with her, and she's willing, at least, to listen. They begin an affair, rent a flat for their rendezvous, and for years enjoy each other's company and intimacy. But somewhere along the line, Robert finds out about the unfaithfulness — of wife and friend both — and, anyway, the infatuation of the two lovers begins to fade.

You might think that the play's unusual structure is revealing: that Pinter wants to illuminate aspects of the Robert-Emma-Jerry triangle that wouldn't at all be so obvious if the play unfolded conventionally. Unfortunately, that's not the case: In a few instances, Pinter shows us scenes in normal sequence, and without fail it's these that have the greatest dramatic effect. For example, after Robert discovers Jerry's adultery, he meets with Jerry in a restaurant. What he says there — and more important, what he doesn't say — makes the encounter tense and potent. But there's no such dramatic payoff when the scenes run backward. I remember seeing a script-in-hand reading of Betrayal soon after the play was published, and the thought I had then was that the work was so banal, Pinter had reversed the usual scene order in a last-ditch effort to be provocative.

All these years later, I'm less willing to guess at the playwright's motives, but seeing the American Stage production, I had the same thought I had decades ago: The back-to-front idea doesn't work. It's at best a failed experiment, at worst a gimmick. Nothing is illuminated.

Still, Pinter's language remains gloriously special, from his rhythmic repetition of innocuous phrases to his bravura explosions of displaced emotion. But the problem with this production is that two of its three main actors don't run with the interpretive opportunities the playwright provides them. Again and again, Kevin Bergen as Jerry speaks Pinter's infinitely ambiguous lines as if only the most obvious surface meaning were all that were in them. Even so, he shows us a fairly wide range of emotion over the play's two acts, which is more than I can say about Drew DeCaro as Robert. His portrayal is two-dimensionally masculine, offering little more than amiability at good moments and bottled anger the rest of the time.

On the other hand, Julie Rowe as Emma begins to explore her dialogue's potential, giving a more emotional reading of her character than I expected, but with such attention to detail that I finally was convinced.

Director Todd Olson has to be faulted for not eliciting more colorful performances from his male actors, though he skillfully moves everyone around Scott Cooper's multi-leveled set with a minimum of confusion. One of Olson's cleverest ideas, by the way, is to place dates around the stage ("1999," "2008"), which light up at the beginning of each scene. The backward movement of Pinter's play may still be confusing, but this device helpfully alleviates the confusion.

I've seen two other full-dress versions of Betrayal, one at Sarasota's Banyan Theatre and the other a film with Jeremy Irons and Ben Kingsley. Despite the play's limitations, both were riveting, the Sarasota production as much as the film, and both for the same reason: superior acting.

The American Stage version is far from riveting; in fact, the longer I watched it, the more bored I became. So just be aware: Betrayal is not the sort of play that made Pinter Pinter. And the American Stage version is, in any case, only moderately successful.