The capital burns.

WASHINGTON is Hollywood for ugly people, the saying goes, which is probably why it's so hard for Hollywood to get Washington quite right: The two cities are like fraternal twins, similar but not quite the same, and the devil always lurks in the details. Filmmakers tend to take the nation's capital much too seriously (see, for instance, the limp cinema verite of HBO's K Street), succumb to Syriana-style conspiracy theorizing, or simply throw up their hands and produce chest-thumping left-wing agitprop like The West Wing or The Contender. As for comedy, the less said the better: You have to understand a place before you can satirize it, and so what passes for political satire is usually just a jokey premise--Chris Rock runs for president! Reese Witherspoon takes Capitol Hill!--with a few Barbra Streisand talking points thrown in for ballast.

Thank You for Smoking, an adaptation of Christopher Buckley's novel, is a cut above this sorry crop--not least because, well, it's an adaptation of a Christopher Buckley novel. The premise alone puts every previous D.C. comedy to shame: The film is a Lobbyist's Progress, with Big Tobacco shill Nick Naylor (Aaron Eckhart) smooth-talking his way through a neo-Puritan world. Eckhart has a shark's grin and the boyish smarm of a man who's spent his life getting away with murder; he's an idealized, sexed-up version of the inside-the-Beltway player--which is to say, the guy that Jack Abramoff and every other K Street wannabe desperately wanted to be. And he's up against a host of other idealized types: his glory-hogging boss (a bellowing J. K. Simmons), who made his bones in the hardscrabble world of cigarette vending machines; a goo-goo senator from Vermont (William H. Macy, doing his usual milquetoast bit) who wants to slap a death's head on cigarette packs; and a femme fatale investigative reporter, repeatedly described in the film as a busty bombshell and played, inexplicably, by Katie Holmes.

Throw in a deadpan Rob Lowe as a Hollywood superagent eager to put cigarettes back on the big screen ("Indiana Jones meets Jerry Maguire . . . on two packs a day"); Robert Duvall as a mintjulep-slurping tobacco baron who takes Naylor under his wing; Sam Elliott as the Marlboro Man, now dying of lung cancer and out for blood (or at least blood money); Naylor's "MOD squad" pals (as in "merchants of death") from the booze and firearms industries, who compare annual death tolls over power lunches; and you have a film that would have to work hard not to be funny. And while first-time director Jason Reitman (son of Ivan, of Stripes and Ghostbusters fame) has rejiggered the novel's narrative, he's wisely kept most of the best lines intact, while showing a flair for quick visual gags: Lowe's Japan-obsessed superagent decked out in a kimono during a late-night call; Naylor unconscious, covered in nicotine patches, and draped seminude over Abraham Lincoln's statue on the Washington Mall by anti-smoking fanatics.

The movie is so breezy, in fact, so charming and perfectly cast (the Holmes puzzler aside), and everyone seems to be having such a good time that it feels almost uncharitable to point out the film's main weakness: the unexpected and unwelcome niceness. Buckley's novel isn't that vicious, as satires go: It doesn't offer the kind of unfiltered misanthropy that you get from Mark Twain or Ambrose Bierce, say. But it's tart and worldly-wise, drained of sentiment and mercifully free of the kind of mourning-over-lost-innocence that pervades too many American political novels, from All the King's Men to Primary Colors. But somewhere during the transition from book to screen, someone (a nervous studio head, perhaps?) seems to have fretted that audiences wouldn't line up to watch a tobacco lobbyist scramble and dissemble his way through a corrupt and self-righteous Washington, D.C. And so Thank You for Smoking acquired ... the Adorable Kid.

In the book, Naylor's son is kept safely offstage; in the movie, he's front and center. And you know what's going to happen as soon as he shows up--given corporeal form by Cameron Bright, who usually plays creepy tykes (a clone in Godsend, Nicole Kidman's reincarnated husband in Birth) but who seems to have mastered the mix of hope, naivety, and secret sorrow that every Adorable Kid needs to carry with him. You know he'll be a child of divorce who's embarrassed by Naylor and somewhat estranged from him; you know that Naylor will take the Kid with him on various excursions (to Hollywood, to the Marlboro Man's house); you know that the two will gradually grow closer, and that Dad will nearly blow it but pull things together in the end, learning a Big Lesson just in time for a stirring, "I'm-so-proud-of-you-Pop" finale.

To Reitman's credit, it's not as bad as it sounds on the page: Naylor's cynicism stays largely intact throughout, and there are some sharp moments amid the predictable father-son bonding. ("My mommy says cigarettes kill," a pigtailed goody-two-shoes tells Naylor when he shows up for his son's career day. "Well, your mommy doesn't sound like a credible medical expert," he shoots back.) The compulsively spinning tobacco lobbyist does become a truth-teller by the end, but at least the Big Lesson that the Adorable Kid helps him learn isn't that Smoking Is Bad. If anything, this film is actually more pro-smoking than Buckley's novel--perhaps because the book came out a decade ago, when the anti-smoking crusade hadn't yet reached the doors of your neighborhood pub.

But a more libertarian Big Lesson is still a lesson, and by the time Naylor finds himself in front of a Senate subcommittee, speaking truth to power with his son looking on, it's clear that Thank You for Smoking hasn't quite broken free of the Hollywood-goes-to-Washington mold. Naylor's D.C. is an entertaining place to visit, but the real city is still awaiting its close-up--and a filmmaker brave enough to realize that great satire doesn't need a message, or a profile in courage, or an Adorable Kid.

Mr. Douthat is an associate editor at The Atlantic Monthly, and the author of Privilege: Harvard and the Education of the Ruling Class.