VENICE - I haven't got my Peanuts archives to hand at the moment, unfortunately, but I think it was that pint-sized sage Linus Van Pelt who once opined that "there is no heavier burden than good intentions." Mira Nair's "The Reluctant Fundamentalist," a commendably argumentative but airlessly diagrammatic plea for parity in the still-ragged post-9/11 dialogue between Islam and the West, feels that strain more than most. A somewhat speciously juiced-up adaptation of Mohsin Hamid's acclaimed 2007 novel, adding a shrill hostage-thriller framework to an otherwise theory-based study of mutable cultural and spiritual identity, it would be typical book-club cinema even without a noble literary source: distributors might want to consider handing a bulleted printout of Points For Discussion to patrons as they leave the cinema.

In a nutshell -- and the film is rather fond of nutshells -- "The Reluctant Fundamentalist" tells the story of Changez (Riz Ahmed), a young, whip-smart Pakistani immigrant whose vertiginous ascent up the Wall Street ladder begins to stall when the grim events of September 2001 raise external barriers of xenophobic American paranoia, not to mention internal concerns of cultural betrayal. It's material that seems tailor-made for the touch of Mira Nair, the maddeningly inconsistent Indian-American director, many of whose best films to date have focused on brittle clashes between Eastern and Western social and political mores, sometimes within a single character.

Modest but searching works like "Mississippi Masala," "Monsoon Wedding" and "The Namesake" negotiated this tricky line of conflict with warmth, good humor and an emphasis on personal and familial idiosyncrasies over broad We Are The World sentiment. Dismayingly, that lightness of touch is scarcely in evidence on her latest, surrendered to the potted, broad-stroke plotting and cloying exoticism that, respectively, hampered "Amelia" and "Vanity Fair," her disastrous forays away from contemporary, ethnicity-oriented storytelling.

"The Reluctant Fundamentalist" is a smarter, more tension-fuelled film than either of those Reader's Digest farragos, but persistently thwarts its most interesting ambiguities by underlining them so emphatically. It's not enough, for example, for Changez's Soho-boho artist girlfriend (Kate Hudson, dispiritingly wan under a dark curtain of Very Serious Hair) to have find her own inadvertent prejudices excavated by their subtly diverging reactions to New York in crisis; she has to stage an implausibly tone-deaf  exhibition titled "I Had A Pakistani," complete with exhortations to "throw on a burqa." It's not enough for the punitive actions of Changez's fatherly, company-guzzling boss (Kiefer Sutherland, amusing in Lane Pryce glasses) to suggest the punitive entitlement of an America heading for a fall; we have to witness a thudding eureka moment when he stresses the importance of "fundamentals" to a boardroom of corporate trainees. Oh, such irony!

The film is, thankfully, a little braver and less lurid when it comes to detailing the purported fundamentalism in Changez himself, who, as the film's ungainly framing device reveals upfront, has since abandoned finance -- and indeed America -- for a career as an influentially radical academic back in Lahore. There's a genuinely jolting moment when he confesses a detached admiration for the terrorist attacks on the US: "The ruthlessness of the act," he says in conversation with a skeptical American journalist played by Liev Schreiber, "was surpassed only by its genius."

It's a line that makes one wish there were an actual character to nourish and contextualize such provocations: though sharply played by exciting British up-and-comer Riz Ahmed, Changez isn't written with enough wit to render him any more than a handsome spout of strong ideas. ("How do I become less interesting?" he asks rhetorically at one point, as if aware of the problem himself.) As such, he doesn't serve Nair's impulse to forge inter-cultural conversation as well as he might, and matters aren't helped by a visual and sonic palette that tends more toward rote Eastern mystique than it really should: an ominous kidnapping sequence at the start, all murkily spotlit jewel tones by usually ace DP Declan Quinn and the percussive world-music overkill of Michael Andrews's strident score, seems particularly ill-judged.

Indeed, that might go for the whole present-day subplot introduced by screenwriter William Wheeler, and not only because the sequences between Ahmed and Schreiber, as the former relates his life story in flashback, are the film's most perfunctorily staged and performed. (Changez's gifts don't extend to narrating: "As the tensions got worse, the biryanis got more delicious," he relates, his face valiantly straight.) More importantly, embellishing the material with genre trappings, while presumably a commercially-minded move, runs counter to the film's stand against fear-mongering, regardless of Changez's culpability.

The Mira Nair of "Mississippi Masala" would have found sufficient dramatic fire and urgency in the protagonist's ample personal conflicts with his family, his colleagues and his lover to make such a stakes-raising gambit redundant; as it is, all the film's characters are straw men in an argument as promisingly heated and finally un-nuanced as those between Anna Paquin's naively righteous Lisa and an opposingly impassioned Middle Eastern classmate in Kenneth Lonergan's "Margaret." That, incidentally, is a film that spoke no less provocatively, and a lot more subtly, about the see-sawing burdens of guilt and martyrdom in post-9/11 America -- without ever being as strenuously About Things as Nair's sporadically stimulating misfire.