More charcoal drawing than portrait in oils, "Ten Unknowns" is the smart and literate latest from Jon Robin Baitz, one of the American theater's smartest and most literate young writers. It's acted with forthright wit and piles of charisma by its cast of four, including a silver-maned Donald Sutherland and the lovely Julianna Margulies, of "ER" fame (looking a bit like Frida Kahlo -- only gorgeous). But this tale of an American painter living in self-imposed exile in Mexico remains a bit sketchy, its characters articulate but distant figures whose conflicts and crises are not compellingly dramatized.

Sutherland plays Malcolm Raphelson, a figurative painter who fled the New York art world nearly three decades before the play begins in 1992. Included in a significant exhibit celebrating "10 Unknowns of 1949," Raphelson later fell afoul of Jackson Pollock "and his homies," as his assistant, Judd Sturgess (Justin Kirk), puts it. Raphelson himself is likewise happy to pontificate on his excommunication from an art world dominated by Abstract Expressionism: "If you suggested that those guys were hiding behind a kind of mock freedom, with those decorator fields of color, those restaurant paintings, washes of -- which was actually a kind of soul-deep conservatism, a refusal to commit -- you were dead." He can get riled, but Malcolm's bitterness has mostly leeched away into the soil of southern Mexico, where he's lived and painted in happy -- if apparently solitary -- exile ever since.

Recently he's been rediscovered, in a minor way, and the aggressive art dealer Trevor Fabricant (Denis O'Hare) hopes to capitalize on his revived appeal in a major way. Trevor, in fact, was responsible for sending Judd down to nudge Malcolm back to the canvas, hoping for a new burst of creativity to complement earlier paintings in a planned retrospective.

And indeed Judd's wry presence seems to have been a tonic: The paintings are now stacked up in a corner of the studio, which is rendered with inviting, ramshackle flair by set designer Ralph Funicello and lit in subtle tones by Pat Collins. As the play proceeds, Trevor tries, first politely and eventually desperately, to get Malcolm's permission to spirit the new work away to New York.

But the artist is proving curiously recalcitrant. One convenient and comely distraction: Margulies' Julia Bryant, a grad student from Berkeley studying the disappearance of frog species in the area. She's invited to join Malcolm's makeshift menage, providing an audience for much acerbic talk about the art world then and now, as well as the increasing exploitation by Yanks of the charms of southern Mexico.

"I suppose the only thing to do is keep moving south, like some German war criminal," quips Malcolm on this subject, as the talk crackles along smartly. Baitz is a master at astute, witty and well-phrased dialogue that tackles topical issues and real ideas with an effortless naturalness (he could be called the American David Hare). U.S. cultural imperialism and artistic trend-mongering are neatly skewered (the latter a bit too neatly, really), with the cynical Malcolm dryly comparing himself to the departing Glass Frog. "Extinction is everything down here," he cracks.

Line by line, the play is intelligent and elegantly written, but the characters often seem to be mere vehicles for their creator's wit, smarts and verbal facility. Take away the provocative attitudes and big vocabularies, and they seem a bit hollow. As a result, it's easy enough to take pleasure in their well-reasoned debates and well-chosen wisecracks, but engaging with the crisis at the heart of the play is rather harder.

This turns on a moral conundrum faced by Malcolm in regard to the authorship of his latest paintings (a taste for drama turning on clearly defined moral questions is another trait Baitz shares with Hare -- and Arthur Miller). Perhaps if we'd warmed to Malcolm -- or to the sulky Judd, played with perhaps a smidge too much sullen sarcasm by Kirk -- this issue might give the play the dramatic momentum it seems intended to inspire.

But Malcolm's character remains opaque -- the motivations for his equivocal behavior are a big question mark. As are Judd's: His much-alluded-to history of drug abuse is no substitute for more thorough characterization. Avoidance may well be an emotional strategy employed by both these characters, but it's not very stageworthy. The behavior of both seems driven more by the exigencies of the plot than any well-defined impulses within them.

Appearing on a New York stage for the first time in 20 years, Sutherland has a nice, laid-back authority. Slouching toward the bottle of mescal whenever things get tense, his Malcolm exudes a rough-edged imperiousness and casual charisma that go some distance toward distracting us from the elements in his character that are unexplored. Although she isn't given much to do, Margulies is a warm, appealing presence and seems thoroughly at home onstage. And O'Hare, a terrifically skilled actor, brings a coiled, cool intensity to the unrewarding role of Trevor, who spends most of his scenes enduring Malcolm's dismissive ire or Judd's sarcastic taunting.

But for all the fine work of the cast under Daniel Sullivan's straightforward direction, the characters have a bloodless quality. There's something, well, abstract about them. We never forget that they're figments of a playwright's imagination, theoretical people whose theoretical fates are being tidily dispatched. At one point Malcolm angrily denounces Pollock and Co. for "veer(ing) away from the human." In its own way Baitz does the same in "Ten Unknowns," substituting intelligence and craft for real heart.

Set, Ralph Funicello; costumes, Jess Goldstein; lighting, Pat Collins; music, Robert Waldman; sound, Janet Kalas; stage manager, Roy Harris. Artistic director, Andre Bishop; executive producer, Bernard Gersten. Opened March 8, 2001. Reviewed March 4. Running time: 1 HOUR, 50 MIN.