No unsightly wrinkle dares to mar the Teflon perfection of Nicole Kidman’s face. With her preternaturally smooth and dome-like forehead yanked somewhere north of her hairline, she wears a permanent wide-eyed and quizzical expression, eyebrows unnaturally arched at a slightly demonic angle. Smooth and featureless, her frighteningly pale skin stretches like high-tensile space-age fabric over her egg-sized cheekbones.

When she tries to smile, the corners of her mouth barely twitch, and her eyes remain uncrinkled — a living model of the “non-Duchenne” or inauthentic smile, which the renowned psychologist Paul Ekman has identified in his Facial Action Coding System. Feelings are never at war on Ms. Kidman’s scarily flawless face. Having long since surrendered to the peaceful miracles of modern medical science, she eerily lacks the ability to express emotion.

In brief, Ms. Kidman resembles an alien, one of those doe-eyed extraterrestrials popular among the UFO crowd, only a lot taller, and Australian. Which is a problem, because anyone who has seen any of the three earlier versions of “The Invasion of the Body Snatchers” (1956, 1978, and 1993) knows that emotional displays are what distinguish real human beings from zombies that only look human. Yet in this latest version of the classic sci-fi thriller, retitled “The Invasion,” Ms. Kidman’s inability to emote makes her look as though her body had been snatched from the very beginning. And there’s another problem with this remake: The leading characters are all played by foreigners — an Aussie and two Brits: Ms. Kidman as the heroine; Daniel Craig as her boyfriend; Jeremy Northam as her ex-husband — even though they are supposed to be Americans living in Washington, D.C. In other words, they’re all aliens in real life. And the difficulty the body snatchers have in fooling people into believing they’re human is nothing compared to the problem the cast has in convincing us they’re Americans.

What’s lost is the emotional wallop of the original film, which was directed with almost unbearable tension by that master of the thriller, Don Siegel. And with the genders reversed in this remake, nothing matches the creepy spectacle of the stunningly beautiful Dana Wynter (as Becky, the hero’s girlfriend in the original film) standing alone, hauntingly lit, in the desert at night. Has she been taken over by an alien being, or is she still human? The original protagonist, played by the square-jawed Kevin McCarthy (Mary’s brother) doesn’t know for sure until he embraces her. And then, in one of the all-time great moments of horrified realization, he says in voice-over, “I never knew fear until I kissed Becky.” We didn’t either.

We did know the original movie was a parable about “mass man,” the bugaboo of postwar intellectuals, including Mary McCarthy’s buddy, Hannah Arendt, the author of “The Origins of Totalitarianism.” When Mr. McCarthy ended the film ranting, “They’re here already! You’re next! You’re next …” it was clear he was warning against the threat of communism. To its credit, the latest remake throws some jabs at simple-minded pacifism. (The movie’s hints of peace in Iraq and President Bush making nice with Hugo Chavez are shown, with irony, as something to be feared — the triumph of alien-induced conformity over humankind’s evolutionary heritage of violence.)

And what happened to the pods? In the original, the aliens hatched duplicates of human beings in slimy pods, which looked like giant zucchinis. The sheer yuck factor of watching a character watch a pod give birth to his double made for another great gross-out moment in the genre. (The idea of the pods was, of course, later lifted for the “Alien” series, which also concerned, um, aliens inhabiting human bodies.) But the latest sequel eliminates the pods and the chilling specter of airborne spores in favor of a perhaps more plausible but considerably less visually horrifying virus. Science, or at least the kind found on film, has triumphed over imagination.

The tagline to “The Invasion,” directed by Oliver Hirschbiegel from a screenplay by Dave Kajganich and based on Jack Finney’s original novel, is “Do not trust anyone. Do not show emotion. Do not fall asleep.” No worries, mate, as they say in Ms. Kidman’s native land — at least not to the first two. It’s only the last of these that could be a problem.