The Phoenix's 'Rancho Mirage' extends the string of new Steven Dietz plays produced here

Six  residents of Rancho Mirage share thinly sliced wry toast.

Achieving a certain level of material comfort represents for many Americans the object of the Declaration of Independence's promise of "the pursuit of happiness." Those people who live in gated communities may fancy that Jeffersonian right a matter of covenant, fleshed out by such details as what outbuildings are permitted and what color you can paint your house.

In the play now being given a "rolling world premiere" at the Phoenix Theatre, the friends who gather at the home of Nick and Diane Dahner expect to revel in the satisfaction of the ingrown social relationships their exclusive neighborhood implicitly celebrates. But in the first scene of Steven Dietz's "Rancho Mirage," the anxiety woven into such friendships seems almost contractual: Is prickly guest Louise partial to a wine called "Menage a Trois" or one called "Three Lovers," and was the wrong wine bought, imperiling the prospective fun?

The Dahners puree that question thoroughly, stirring in concern about how well they really know Louise and her possibly estranged husband Trevor. The couple rehearses the matters that can't be raised with either that couple or Charlie and Pam Caldwell. Nick Dahner plops an LP onto his trendy turntable. It's Miles Davis playing "So What." The cool modernist chic is reflected in Dan Tracy's set for this production, perfect insofar as contemporary interior design both proclaims personality and subtly masks it lest visitors find out too much (unless they peek into closets and garages).

And so we are off to the races in this searing comedy about secrets and their bad habit of coming out at the worst times. Social life is centered on couples, so much so that one guest is initially ignored because her husband is late to the party. Children, even ones not yet in actual Rancho Mirage households, are primarily pawns and bargaining chips in earnest adult games.

Dietz's characters are not temperamentally secretive, but prone to bluntness, needling and flashes of resentment they freely give voice to. That generates a lot of the humor, but most of the rawness as well. "Rancho Mirage" is so relentless in peeling off layers of the six characters' lives that it begins to have the feeling of farce. That's a dangerous direction for a play to go in if it's trying to ground an audience's sympathy in real human problems, but I think the playwright brings it off.

A less assured production might have made such relentless unveiling tedious, but Bryan Fonseca directs a cast that takes pains to take pain seriously and let the laughs take care of themselves. In the course of two acts, the upscale friendships are torn to shreds. Only the savage sustenance the six wounded grownups get from revelations about "the very best people we know" helps them survive to make a video-recorded show of peace at the end.

It's no accident that the play's setting is drolly described in the program as "the Dahner Party," a pun on the infamous Donner Party of the 1840s, which pushed west through early snows toward California, got trapped south of Great Salt Lake and managed to enable the survival of about half the group by resorting to cannibalism. The American dream has taken many damaging forms, and in "Rancho Mirage" is subject to crippling emotional and financial privation. If we eat each other alive along the way ... well, we're living the dream, aren't we?

Earl Campbell and Jolene Mentink Moffatt played with assurance the uneasy Dahners, gamely covering up impending financial ruin and exile from their fragile, restrictive paradise. As Trevor Neese, Bill Simmons, playing one of the aggressive blowhards he does so well, made a fierce sparring partner for Sara Riemen as the tactless Louise, who is trying to live down a promiscuous past without much in the way of spiritual resources.

Spiritual resources are exactly what  Joshua Coomer's Charlie Caldwell believes he has to draw upon, The foreign-adoption scenario he has envisioned to resolve ambivalence about his and wife Pam's childlessness fortunately gives the play backbone. What might otherwise seem a parade of bickering and "gotcha" moments takes on dignity and poignancy as a result. We learn, for example, how vague a notion the Rancho Mirage residents have of life outside their privileged environment. Diane Timmerman plays Pam with a nice sense of keeping up appearances and tolerating her husband's unfashionable Christianity, though her character's vulnerability makes her susceptible to Charlie's altruistic fantasies.

Though Dietz doesn't hit the religious note hard, Charlie seems a character in the mold of the apostle Paul. He's too insulated to have had a road-to-Damascus conversion, but his yearning to capture life with his camera bespeaks a need to bear witness to a truth he alone of this group can see. He may lack Paul's self-assurance, but he has that spiritual warrior's intellectual seriousness and sense of mission. He evidently sees beyond the edge of the mirage. What comes into view may be only another mirage, but as Paul famously says (often misquoted with the insertion of "and be merry"): "What advantageth it me, if the dead rise not? Let us eat and drink, for tomorrow we die."

What happens in the last scene is shadowed by some of the play's tendency toward farce, but it also points to a resolution of an unexpected kind, one that will not need to strike like lightning to be long-lasting. As the poet Rita Dove has written in an essay on the Pauline Epistle to the Ephesians: "Grace is a state of being, not an assault; and enlightenment, unlike epiphany, is neither brief nor particularly felicitous."  That's far from a process that any covenant for a gated community can stipulate, and it's what faces the people of "Rancho Mirage" as they start sifting through the mess they've made.