The U.S. government's use of Navajo Marines to transmit encrypted military information during the Pacific battles of World War II is one of those amazing, little-known sidebar stories of wartime ingenuity, patriotism, and bravery on which victory turned. Because the Navajo language relies so much on complex, subtle nuances of pronunciation, these code talkers, as they were called, were able to translate code into their own tongue -- the Navajo word for ''hummingbird'' meant fighter plane, for instance, and ''beaver'' meant mine sweeper -- and elude the Japanese who had broken every other enciphered transmission. Beginning in 1942, some 400 Navajo men were eventually trained as code talkers, and the specialists were considered so crucial to winning the war that they were guarded by fellow Marines.
This particular amazing, little-known sidebar story, is, however, not so easily adapted to movie purposes -- how do you dramatize the sedentary activity of donning radio headsets for a cause? The solution in Windtalkers, a big, old-fashioned American war pic of the ''every guy in the unit signifies a type'' variety, seizes on the notion that those Marine guards were more concerned with protecting the code itself than the lives of its talkers. The movie is a history lesson that leans hard on the dramatic potential of a hypothetical: Not that there's any record that such a thing happened (and not that it's legal for a Marine to be ordered to kill a fellow Marine), but would or could a patriotic, moral soldier take the life of one of his own comrades who has fallen into enemy hands for the greater good of the mission?
''Windtalkers'' billows and bulges with scenes of angst and soldierly bonding. As Joe Enders, a battle-scarred sergeant assigned to guard Ben Yahzee (Adam Beach), Nicolas Cage winces with Ambivalent Hero Fatigue. Christian Slater, as easygoing Marine guard Ox Anderson, milks the pauses between combat for all they're worth by wah-wahing on a harmonica in the gloaming, accompanied by the Navajo he's assigned to protect, Charlie Whitehorse (Roger Willie), on wooden flute. In a clunky, educational demonstration of the sins of bigotry, belligerent squad member Chick (Noah Emmerich), sinks to ''Injun'' baiting. But since the movie is directed by John Woo, the drama trains its sights on Woo's favorite target, duty and friendship caught in the crosshairs.
What really interests the filmmaker -- famed for his action sequences but fascinated, as seen in such Chow Yun-Fat-powered Hong Kong classics as ''The Killer'' (1989) and ''Hard-Boiled'' (1992), by the spiritual dimensions of the standoff -- is how a pair of Navajo Marines relate to the non-Navajo soldiers assigned to protect them. What turns him on is how those relationships between men shift, strain, deepen, and are reconfigured by chance and choice. And though this makes for an unsteadily stacked story -- we barely learn how the code talkers did what they did, and Navajo off-duty life, as depicted, is a never-ending pageant of sacred ritual solemnized by wood smoke and sunsets -- it also makes for a fascinating Woo movie. ''Windtalkers'' is a fresh contribution to the cinematic literature of American WWII movies from a Chinese-born director with a flair for the imagery of spiritual battle.
Real battle, too. Woo re-creates the 1944 Battle of Saipan as a sweep and jumble of madly busy vista -- men running, shooting, dying, spurting blood -- and intimate detail. And he embeds his action with the various signature images Woo-ists look forward to: Wings flap overhead (not doves this time, but avian none the less). Enders pauses in a ruined Japanese hut to tend to a sick child. He draws a picture of a Christian church in the flour dusting a kitchen table. Then it's back to battle.
The script, by John Rice and Joe Batteer, teeters between the blunt (''What a magical pile of Navajo horses---,'' Chick sneers at Whitehorse), the didactic (''It's my war, too, Sergeant,'' Yahzee informs Enders), and the what-the-hell (Fifty years from now we may be ''sittin' down with the Nipponese drinkin' saki,'' that same chatty Chick marvels, miraculously gone psychic). But Woo restrains his cast, going for underplayed performances that step nimbly over the worst script landmines -- and stay out of the way of ''Windtalkers''' bigger, wordless ambitions. Cage and Slater, who have each worked with the director before (on ''Face/Off'' and ''Broken Arrow,'' respectively), display a respectful modulation that keeps the focus on the ensemble, while Beach (''Smoke Signals'') and, especially, the Navajo newcomer Willie are never overwhelmed by the patriotic mantle they're assigned to carry.
''Windtalkers'' blows this way and that, but there's no mistaking the filmmaker in the tall grass, true to himself. Besides which, he leaves a visual calling card: In one tense confrontation, Chick and Yahzee face each other with guns drawn and pointed at the other man's face. The gesture is code for ''John Woo was here.''