"If you argue correctly, you're never wrong." It's a motto Nick Naylor (Aaron Eckhart) believes in and lives by, both from experience and out of necessity. As a leading Washington, D.C.-based lobbyist working for the Academy of Tobacco Studies, Nick has built his career on defending the tobacco companies, persuasively debating against anti-smoking pundits, and aiding in advertisements targeting the teenage demographic. It's not exactly the most virtuous of jobs, and his work has left him publicly reviled, but Nick takes it very seriously, believing in one's freedom to choose whether he or she wants to smoke or not. Of course, it doesn't hurt matters that he's a keen businessman who, by basically BS-ing his way through debates opposing his side, is able to argue skillfully, and yes, in a strange way, never be wrong.

Written and directed with lightning-fast precision by Jason Reitman (son of Ivan Reitman), "Thank You for Smoking" is of a cinematic breed that doesn't often show itself: a comedy that not only succeeds at getting laughs, but also is thought-provoking. An ultra-smart, all-opportunity satire in which no one is safe, the movie doesn't just point the finger at Big Tobacco, but at everyone, from big-headed D.C. politicians and senators, to story-hungry reporters, to even pretentious Hollywood studio bigwigs. The film works, sometimes brilliantly, at seriously exposing the flaws and hypocrisy within American government and business, all the while keeping a biting, sarcastically funny tone. This material, adapted from a novel by Christopher Buckley, couldn't have been easy to tackle, but Reitman is fully up to the challenge.

The large ensemble of exceptionally fine actors ravish their roles—even the ones that are a little negligently developed on the page—as if it's their first meal in months. Prime among them is Aaron Eckhart (2004's "Suspect Zero"), whose stupendously charismatic and layered work deserves to be remembered come next Oscar season. Eckhart's Nick Naylor isn't a bad man, and yet he has embraced a tobacco lobbyist profession that could be considered immoral in the job description's overall purposes. Furthermore, he appears to be more than willing to teach his impressionable 12-year-old son, Joey (Cameron Bright), the tricks of the trade and the value of persuasion and charm in driving home any stance of an argument. Even when the question is raised as to whether Joey's exposure to his father's work is healthy for him, Nick always seems to have an answer to silence them. That is Nick's job, after all. Eckhart is simply fabulous as a man who presents a sure-headed persona to the public—even in the face of harsh criticism—that doesn't always coincide with who he is behind closed doors. The changes he goes through during the course of the film, most of them subtle but impacting, hold an unsentimental emotion and gravity, especially as they relate to his loving, respectful relationship with son Joey.

The support Aaron Eckhart gets from his co-stars is invaluable. In his third (and best) film role in less than a month, Cameron Bright (2006's "Running Scared" and "Ultraviolet") is a delight as Joey Naylor. Joey's adoring bond with his father is the real heart of the picture—that one genuine glimpse of compassion and love that is necessary to balance the rest of the film's ruthlessly acerbic nature—and Bright, for once not be placed into immediate peril or being the antagonist himself, embraces the chance at getting to act as a more normal representation than he's accustomed to of a kid his age.

In other memorable turns, Sam Elliott (2003's "Hulk") is powerful and commanding as former Marlboro Man Lorne Lutch, now dying of lung cancer, who Nick is sent to pay off in exchange for his silence against the tobacco companies; Katie Holmes (2005's "Batman Begins") plays deliciously against-type as cutthroat journalist Heather Holloway, who will do anything (and sleep with anyone) to get her story; Maria Bello (2004's "Silver City") and David Koechner (2005's "Waiting...") are hilarious as Polly Bailey and Bobby Jay Bliss, eternally harried lobbyists for the alcohol and firearm departments who meet regularly with Nick to swap war stories; and William H. Macy (2005's "Sahara") is right on target as Senator Ortolan Finistirre, whose do-gooder wish to place poison symbols on cigarette packs makes for an ironic counterpoint to past personal indiscretions he'd rather keep silent.

Writer-director Jason Reitman does a cohesive, satisfying job at interweaving and bringing to life his diverse group of characters. In this way and in its subject matter, "Thank You for Smoking" actually makes for an ideal comic companion piece to 1999's more dramatic, equally thoughtful "The Insider." The one area where Reitman's work uncovers a seam is in its length, or lack thereof. At 92 minutes (this includes a long opening titles sequence and the end credits), the film is too short to do unadulterated justice to its every subplot and character. When Nick travels to Los Angeles to discuss with Entertainment Global Operations (EGO) head Jeff Megall (Rob Lowe) about increasing smoking by glamorous stars in the movies being made, there is a brief suggestion that more razor-sharp commentary about the Hollywood studio system is to come. Unfortunately, these short scenes don't really lead anywhere, hinging on broad stereotypes and throwaway racist remarks that go against the rest of the film's quick-witted perceptiveness. Katie Holmes' newspaper gal Heather Holloway also could have used some more shaping so that her actions in the third act appeared to be more complicated than easy one-dimensional villainy.

Fair-minded and frequently penetrating, "Thank You for Smoking" moves effortlessly from riotous to darkly humorous to poignant, creating an all-cylinders pastiche of the ongoing, determinedly fruitless fight against a highly addictive drug that aids in killing thousands of people a year. Really, director Jason Reitman has evaded any and all preachy inclinations to tell a story less about smoking and more about democracy in America—freedom of speech, freedom of the press, freedom to fight for what we believe in—and our sometimes skewed vision of what such a thing constitutes. "Thank You for Smoking" is no dry history lesson, though, although it should be a rich conversation piece for adult audiences. More than anything, the film is rousing, ballsy, and purely entertaining in a big way.