Ambitiously directed by Emilio Estevez (1996's "The War at Home"), "Bobby" uses a tragic real-life event—the assassination of U.S. Senator Robert F. Kennedy at L.A.'s Ambassador Hotel on June 5, 1968—as the destination for twenty-three fictionalized characters who become the unwitting witnesses, bystanders and, in some cases, victims to a life-changing moment in American history. With a sprawling ensemble of interweaving and intersecting storylines and people—hotel workers, guests, political aides, etc.—the film is purely Altman-esque in structure, though a little more broad, obvious and calculated in its telling.

Eerily reminiscent in many ways to Altman's 1975 masterpiece, "Nashville," which also culminated in an assassination, Estevez tends to spell things out for the viewer and always seems to be strenuously aiming to make big statements. In comparison, Altman allowed his characters to live and act in a more naturalistic fashion, and gave his audience the leeway to draw their own conclusions and formulate their own theories on the picture's social and political relevance. "Bobby" sweeps the viewer up in its own right, drifting smoothly from one set of characters to the next and never overstaying its welcome, but the occasionally forced material threatens to become monotonous. In his uneven screenplay, Estevez does not write believable back-and-forth dialogue, but long speeches and monologues that ring false. Had he stepped back and let his characters breathe rather than continuously making sure that an "important" point was being made, the film would have been better for it.

As a cinematic and historical microcosm of who we as an American people were in 1968 and who we now are in 2006, however, the problematic "Bobby" remains a stirring dramatic mosaic of crushed dreams, broken ideals and mounting cynicism in a strife-filled landscape. All of the racial, socioeconomic and political bases are covered by the characters inhabiting the Ambassador Hotel on June 4, 1968, the fateful day of the California Primaries and the eve of Robert F. Kennedy's death.

Recently retired doorman John Casey (Anthony Hopkins) clings to his memories of the hotel and waxes philosophic about days gone by while playing chess in the lobby. Hotel manager Paul Ebbers (William H. Macy) has his hands full with racist kitchen boss Timmons (Christian Slater), a mistress in switchboard operator Angela (Heather Graham), and a wife in kindly beautician Miriam (Sharon Stone). The kitchen staff includes philosophical black chef Edward Robinson (Laurence Fishburne) and downtrodden Mexican-American Jose (Freddy Rodriguez), the latter disappointed about having to work a double shift instead of attending the Dodgers game. Washed-up singer Virginia Fallon (Demi Moore) is about to perform her last night at the Ambassador, while husband Tim (Emilio Estevez) feels hopeless in watching his abusive fallen star of a spouse drink herself into oblivion.

There's more characters where those come from. The college-aged Diane (Lindsay Lohan) is preparing to marry classmate William (Elijah Wood) in an effort to keep him out of Vietnam. Manhattan socialites Samantha (Helen Hunt) and Jack Stevens (Martin Sheen) are celebrating their anniversary at the hotel, but all Samantha seems concerned about is buying a black pair of shoes to match the outfit she plans to wear to Kennedy's speech. Czech journalist Lenka Janacek (Svetlana Metkina) desperately wants an interview with Kennedy, but PR aide Wade (Joshua Jackson) rebuffs her attempts by labeling her a Communist. Cafe waitress Susan (Mary Elizabeth Winstead), fresh off the bus from Ohio, dreams of becoming a Hollywood actress. And wet-behind-the-ears junior aides Cooper (Brian Geraghty) and Jimmy (Shia LaBeouf) take a detour to the hotel room of a drug dealer (Ashton Kutcher) and end up going on a day-long acid trip. Most of these figures and several more finally converge for Robert F. Kennedy's much-publicized speech, given only moments before the shots rang out in the kitchen that would claim Kennedy's life and injure five others.

"Bobby" has so much going on that if a particular subplot doesn't strike one's fancy, the viewer can rest assured that another one will be picked up a few seconds later. Some aren't developed enough to hold much substance, as in the relationship between married couple Samantha and Jack, the latter grown depressed by his wife's materialism. Others are preachy and staged awkwardly, as in most of the kitchen scenes where Edward prattles on and on with lugubrious monologues about race and class status. A few show promise—weary switchboard operator Angela, prejudicial kitchen manager Timmons, and engaged friends Diane and William spring to mind—but not the screen time to explore their characters in three-dimensional terms.

Meanwhile, the more involving stories pack a wallop, and they feature the best performances to go along with them. Demi Moore (2003's "Charlie's Angels: Full Throttle") is astonishing as the boozy Virginia Fallon, delivering a fierce and courageous portrayal of an aging star afraid to admit she is on her way down. Sharon Stone (2006's "Basic Instinct 2") is heartbreaking and vulnerable in a way she has never been before as soft-spoken beautician Miriam, who discovers her husband's unsavory extracurricular activities through an unexpected third party. Moore and Stone share one of the best scene in the picture—an acting tour de force that hits all the right dramatic notes—as Virginia comes clean to Miriam about the hateful person she has become. Finally, the usually over-the-top Nick Cannon (2003's "Love Don't Cost a Thing") is shockingly good and beautifully understated as disenfranchised Kennedy aide Dwayne, whose old idealism is reclaimed all too briefly when Kennedy himself shows him an act of gratitude.

"Bobby" ends with the inevitable, the chaos of the shootings and the reactions of the people in the Ambassador powerfully and ironically overlaid by Robert F. Kennedy's final speech to the people, rich in inspiration and hope for a country he loved and a future he would never get to see take shape. The effectiveness of this finale reverberates with the knowledge that in the present day, nearly forty years after Kennedy's assassination, many of the same political conflicts and issues are still disturbingly relevant. "Bobby" doesn't get everything right—far from it—but when writer-director Emilio Estevez allows his images and the reality of his characters do the talking instead of the overwrought, self-important dialogue he has constructed for them, the film works with indelible cogency.