THE MOST EXPENSIVE ANTI-IRAQ-WAR FILM EVER MADE, Avatar makes explicitly political the vague populism of such previous James Cameron spectaculars as Titanic. Of course, the writer-director's creative universe consists almost entirely of new FX and old movies, so his latest adventure is foremost an extrapolation of such gone-native Hollywood flicks as A Man Called Horse, Dances with Wolves, and (yup) The Last Samurai. (Cameron even found a part for veteran Native American actor Wes Studi.) But there's a hint of the modestly budgeted The Men Who Stared at Goats in this $230-million vision of ex-military contractors at war with the ecologically pure residents of a mineral-rich planet that's basically the Amazon rainforest.

The planet is Pandora, and it's populated by the 10-foot-tall Na'vi, nature children who are blue, striped, feline, deer-eared, and tree-worshipping. (In other words, part cat, part Celt, and part Smurf.) Unfortunately, they resemble Jar Jar Binks, which exemplifies one of the Avatar's major problems: It's a mix-and-match jumble that rarely hits on anything to call its own. Add a predictable and timid script, and the result is a movie that could barely justify 90 minutes, let alone this one's 161. Oh yeah, and it's in 3D, so both the images and the clichés will have you rubbing your eyes.

The film opens with a swooping shot of Pandora, whose jungles are half simulated nature documentary, half videogame backdrop. About to hit the surface is our hero, Jake Sully (Sam Worthington), Cameron's latest daydream of weakness made strong with futuristic technology. A veteran soldier, Jake lost the use of his legs in some battle or another. Now he's getting another chance to walk, but only in his mind: He'll lie in a capsule while his brain controls his "avatar," a biracial clone who looks 100 percent Na'vi but includes some human DNA. (Don't worry about how this might actually work — Cameron sure didn't. Recent reports that the filmmaker got beat up a lot in high school explain Jake's towering alter ego better than any genetic speculation could.)

One of many veterans who now work for "the company" — call it BlackholeWater — Jake has combat experience in Nigeria and Venezuela. (But not Vietnam, which doesn't stop Avatar from recalling Apocalypse Now once the choppers begin attacking and the napalm starts burning). On Pandora, Jake is given conflicting missions. The nice job comes from outer-space anthropologist Grace Augustine (Sigourney Weaver), a fellow avatar pilot who wants her new recruit to regain the trust of the Na'vi. (Some of them used to attend a Earthling-sponsored school, where they learned enough English that Cameron doesn't have to use much of the fake language he had created for the natives.) The nasty duty is assigned by corporate weasel Carter Selfridge (Giovanni Ribisi) and his ex-military attach´, Col. Miles Quaritch (Stephen Lang, who played a similar role in The Men Who Stared at Goats). They expect Jake to displace the locals so the company can begin extracting an essential mineral called — yeah, whatever — unobtainium.

On his first amble through the rainforest, Jake is both entranced and menaced. Pandora's jungle looks Amazonian, but with qualities clearly derived from Cameron's beloved undersea environs: Luminescent plants suggest creatures from the lower depths, and floating "seeds of the sacred tree" resemble airborne jellyfish. (Basically, Pandora is nature as a black-light poster.) The other visual trick is a matter of scale: Plants are so large that they dwarf even the towering Na'vi, making the aboriginals look like munchkins — which is to say, kinda cute. Despite abundant apparent dangers, the planet is not really sinister; the genuine threat comes from the American mercenaries sent to plunder Eden's resources.

Jake soon faces hostile creatures that look like hammerhead Stegosauruses, as well some snarling dinosaur-dingoes. He's rescued by Neytiri (Zoë Saldana), a blue-skinned babe with a barely pubescent figure. (If there's any human DNA in her, it's Kate Moss's.) Perhaps because he was distracted by new 3D cameras and improved motion-capture techniques, Cameron just grabbed the standard Romeo and Juliet plot: Neytiri and Jake fall in love, despite being the children of warring clans. But Jake can't bring himself to tell his new love that he works for people who want to banish her tribe from paradise.

When their minds are not animating their avatars, Grace, Jake, and a few other good guys relocate their operation to a floating mountain strongly reminiscent of Miyazaki's Castle in the Sky. The goal is escape interference from BlackholeWater, but that only works for so long. Eventually, the military-mining complex attacks both the Na'vi and the avatar control center, and the final showdown between Jake and Col. Quaritch is much like the one in District 9, another movie Avatar resembles all too closely.

For a grand personal statement that's reportedly been gestating for decades, Avatar is a disappointingly clunky and secondhand. But Cameron might be forgiven his underwritten script — which is, after all, entirely typical of contemporary Hollywood — if his images can upstage the story. They do, but only some of the time. Certainly Cameron uses 3D and motion-capture more skillfully than his principal competitor, Robert Zemeckis. The Na'vi are far more lifelike than the zombie tots of The Polar Express or the eminently un-Victorian 'toons of A Christmas Carol, and Avatar's 3D largely avoids the crudely priapic flourishes of Beowulf. (Is that a sword in my eye, or are you just glad to see me?)

And yet Avatar's virtual reality rarely feel real. Aided by immersive "camera" angles and sheer vertigo, sequences of dino-bird bareback riding and scrambles up floating-in-air foothills are pretty thrilling. But much of the movement is jerky, and the overall picture quality is too soft. If Pandora had been discovered by National Geographic, the pictures would be a lot crisper than this.

Derived from Sanskrit, "avatar" originally referred to a Hindu god in human form. The gods of Avatar are, of course, behind the camera. As for the characters on screen, they're barely human, whether they're all or only partly CGI. The final battle yields a significant death toll, but nothing is truly tragic here, since major characters's lives can be restored by either Earthling science or Na'vi magic. (Attempts to explain the natives's nature-consciousness as a sort of eco-Internet are just more new-age bluster.) This isn't Titanic, which astonished its 'tween audience by acknowledging that in real life not only bit players die. (Although James Horner's huge-yet-thin score does continually tease with the first three notes of Titanic's love theme.)

Avatar is a overstuffed grab-bag, so perhaps it's just a coincidence that its anti-imperialist message is so redolent of Iraq. But as the natives band together to fight the invaders, Col. Quaritch shifts into full-Rumsfeld mode and tell his troops that "we will fight terror with terror" with a "shock and awe" campaign. It's this element, however cursory, that gives the movie some punch. No matter how artificial our environments become, Avatar reassures, we'll always have counterinsurgency.

AVATAR — 2009, 161 min; showing throughout the universe.