It's an ominous, soul-cutting, deep-in-the-gut sound, and it comes to us at the beginning of "Apocalypse Now," as if through a thick sludge, slowed down, thwack, thwack, thwack, thwack, thwack, like a sickening echo -- the sound of death. Accompanying the sound is a miragelike vision. Choppers circle over palms, deep-green, rotors cutting through the air, dropping tall columns of bright orange fire behind them. The image -- a resonant, humbling, primal image, like a pop hallucination of deadly ghosts in flight -- is ravishing. Apocalypse, beautiful apocalypse.

In 1979, when Francis Coppola released "Apocalypse Now" after the arduous, two-year-long struggle to make it, there was excitement, but no one seemed to be particularly ready to deal with it. The wound caused by the war in Vietnam had just closed and was still too sensitive for probing. Getting over it, forgetting it, was the order of the day. Just the idea of Coppola offering up his grandiose, druggy summation seemed an affront, an act of bad taste, bad faith. And the response was, "Go away, man, we don't care if it is brilliant. We don't want it."

Eight years later -- and 12 years after the end of the war itself -- we can't seem to get enough. Maybe it's simply a matter of timing, of things coming around. But now there are Vietnam movies everywhere. It's as if we were reliving the experience, this time on film, running the images through our brains over and over again, sorting through them, absorbing them, trying to make the pieces fit.

So far this year, Coppola's "Gardens of Stone," Lionel Chetwynd's "The Hanoi Hilton" and, most recently, Stanley Kubrick's "Full Metal Jacket" have been released. Another, John Irvin's "Hamburger Hill," will be out before the end of the summer and several others, among them "Good Morning, Vietnam" with Robin Williams, "Bat-21" and "Saigon" with Willem Dafoe and Gregory Hines, are in production. There's even talk of re-releasing the 1978 film "Go Tell the Spartans."

The success of Oliver Stone's "Platoon," which not only found popular and critical support but won Academy Awards for best picture and best director as well, marked a turn in the river for Vietnam war movies. And the change it demonstrated was that Americans seemed to want to see the war depicted on screen, that they needed to work through their feeling about the war and that here, at last, was a movie that allowed them, helped them, to do so.

But Stone's movie did manage in some manner to open up an unofficial forum on the war, to provoke discourse and dredge up old feelings, long buried and (supposedly) forgotten. In Stanley Kubrick's "Full Metal Jacket," the discourse continues. And comparisons between it and "Platoon" are inevitable. But the two movies have almost nothing in common.

"Full Metal Jacket" isn't Kubrick's effort to purge the war from his system as Stone's film was. It's not an attempt to work through the experience and to come to some peace with it. What we seemed to need was less an explanation of what happened in Vietnam than an honest description of it -- a sense of what it looked like, felt like, how it smelled.

Real-life images -- like the ones we saw in the documentaries on the subject or every night, over and over again, on the news -- didn't quite capture the experience, though, in theory, they should have. Something was missing. Something essential. The war remained incomprehensible to us; it wouldn't come clear in our heads.

The issue that "Platoon" addressed -- and that the movies themselves appear best equipped to deal with -- seemed to be, what kind of war were we involved in over there? And, more indirectly, what did it do to us? What distinguishes "Platoon" from "Full Metal Jacket" and the other Vietnam war movies is that it was the first of the films conceived to deal with these questions in mass audience terms -- that was designed to communicate to the larger public what, from a soldier's point of view, the war was like.

In this regard, "Platoon" seemed to have a head-clearing effect. No other film about Vietnam, before or since, could make that claim. What's most remarkable about these new movies is how hot the subject is, how urgent and close to the surface our responses are. America is a country with a short attention span, and decade-old news is ancient history. But the reactions to "Platoon" didn't have the mulled-over, talked-over, seen-in-perspective flavor that events viewed from a historical distance usually have. Perhaps the public was caught unawares, with its defenses down, but its reaction was impassioned, visceral, as if the war had just ended yesterday.

This was not true of the response to any of the other films that took the war as its subject, even if they struck a chord, as Michael Cimino's "The Deer Hunter" and Hal Ashby's "Coming Home" seem to have done. "The Deer Hunter," for all its stirring, monumental imagery, was too unformed in its thinking, and too caught up in the exploration of its themes of male bonding and camaraderie, to have much meaning for the mass audience. "Apocalypse," also, may have been too personal a vision, too lost in its mixture of Conrad and Frasier and Eliot, for a clear, clean, unadulterated picture of the war to emerge. And none of the other films -- the less ambitious, less audacious ventures into the area -- were sufficiently grand, in scale and imagination, to do justice to their subject. Even a movie like "Coming Home," which began as an attempt to tackle the issue of the disabled vet but shifted its focus to include the political coming of age of its heroine, was simply too puny to get its foot in the door.

Where "Platoon" stays with the small details of the conflict -- the places where it sticks our noses smack in the itchy, wet, bug-infested realities of war in the bush -- it is unrelentingly, harrowingly brilliant. It is in the broader strokes -- in the Melvillian, good sergeant-evil sergeant structure, its splitting the platoon itself into prowar/antiwar factions that mirror the dissension back home -- that the movie is less successful. In review after review, critics praised the movie for its straightforward, realistic portrayal of the battle front, and as far as the actual battle scenes go they are correct. But Stone was just as eager to present the war in metaphorical terms as either Coppola or Cimino was.

What saves Stone, as far as the mass audience goes, is the simple-mindedness of his metaphorical ideas. Though he has grown in stature as a director, as a writer his work is rudimentary. But it is that the movie was so explicit, and Stone so eager to make his feelings accessible, no matter how unsubtly, that to a large degree accounts for "Platoon's" mass appeal.

Kubrick's vision of the war in "Full Metal Jacket" could, in a sense, be termed both more concentrated and more generic than Stone's. His movie is not about war, it's about killing.

From the opening shots of the recruits receiving their savage GI buzz-cuts -- it's the rape of the lock, for real -- Kubrick's attitude toward his characters is clear; they're chattel, sheep for the shearing, and they submit to their scalping in an appropriately blank, impassive manner, their eyes giving nothing away.

But giving something away would, of course, go against Kubrick's thesis; it would display a spark of individuality and spoil his portrayal of them as mindless droids. The first half of the film, which takes place in Parris Island, S.C., concentrates on the recruits' basic training. Most of the scenes focus on the bellowing sadism of Gunny Sgt. Hartman (Lee Ermey), who badgers his men into submission, smacks them when it pleases him (and it pleases him often) and even chokes one hapless, blobby soldier, Pvt. Pyle (Vincent D'Onofrio), who can't contain his own smirky joy over the entertainment value of seeing his fellow boot campers abused.

The choking scene, I think, is where Kubrick gives himself away; it's where he establishes his relationship to his audience. And what the scene tells us is that Kubrick wants to wipe that smile off our faces.

There's nothing in the boot camp scenes in "Full Metal Jacket" that we haven't seen before -- in "Sands of Iwo Jima" or "An Officer and a Gentleman" or, more recently, "Heartbreak Ridge" and "Gardens of Stone." It's venerable war movie material. The only real difference here is that Kubrick gives the thumbscrews an extra turn. The soldiers have been stripped of all personal characteristics -- no class backgrounds, home towns or reasons for joining up -- and, until a little later on, they're given only the tiniest opportunity to engage in any sort of casual talk. Perhaps what Kubrick would like to suggest is that this first half is not only the soldiers' initiation but ours as well, and that he's preparing us for the horrors to come in just the same manner that the drill instructor prepares his charges.

Such an interpretation, though, would give the director much too much credit for a concern for his audience. To say that Kubrick has a cold, misanthropic sensibility would be an understatement. In his 1968 film "2001: A Space Odyssey," he showed in the battle of the apes that what gave man his evolutionary leg up was the discovery of his potential for violence, his power to kill. When we learned to murder, he told us, we became men.

A similar coming into manhood is staged at the end of "Full Metal Jacket" when a young soldier, Pvt. Joker (Matthew Modine), comes face to face with a mortally wounded Viet Cong girl -- the only direct glimpse of the enemy we're given -- who has just killed his best friend. The image of the girl, splayed out on the floor and begging for one of the soldiers to end her suffering and shoot her, is held on the screen interminably, in close-up. And in the hands of another director, the unendurable suspension of time might have great emotional weight; we might think that this is how the moment might play itself out in the minds of the soldiers there on the scene, how it might come back to them in their nightmares. But with Kubrick, the shot loses its meaning; you're not sure what he's getting at, and so the image is close to being pornographic. When the climax to the scene comes -- and the boy goes through his rite of passage, much as the young soldier Chris (Charlie Sheen) gets his macho merit badge by killing the death-loving Barnes in "Platoon" -- all you feel is let off the hook, relieved that the torture is over.

You may also feel a sense of outrage -- at the brutality of the imagery, at the fact that the enemy is portrayed as a pigtailed girl, at the glib nihilism of the movie's final shot, in which the soldiers, after their day in battle, march out from amid the burning rubble singing the Mousekateer song. Americans: fighting to make the world free for Disneyland.

"Full Metal Jacket" is not Kubrick's anti-Vietnam movie; it's his the-white-race-is-the cancer-of-the-world movie. The battle sequences, which all take place in the film's longer, second half, focus on the fighting during the 1968 Tet offensive in the city of Hue. And the point of staging the battles in urban areas, which was atypical of the fighting in Vietnam, is to sever the specific connections to the conflict in Southeast Asia in favor of a more universal, generalized, knee-jerk statement. Kubrick's views on this war, or war in general, aren't illuminating or even particularly well articulated. Primarily, what he's giving vent to is white American guilt and masculine self-hatred. He boils his observations down to a pat formula: The kind of killing we did in Vietnam is the same killing we've done throughout history, the whole world over. His views as they are presented are more prejudices than judgments, and the level of his anti-Americanism is as shallow as the jingoistic pro-Americanism of the "Rambo" films or "Heartbreak Ridge."

In "Full Metal Jacket," Kubrick shows that he's the kind of artist who likes to make blanket indictments and then cover himself with feeble ironies, like the peace symbol Joker wears along with his Born to Kill helmet, or the scene where the drill sergeant points proudly to Lee Harvey Oswald and the University of Texas sniper Charles Whitman as examples of what a motivated marine and his rifle can accomplish. But what we're to make of this scene -- whether we're supposed to laugh at the grim comedy or blanch at its horror -- is left up in the air. It's mute.

The movie is a strange mixture of hostility and affectlessness. The clinical blankness comes from Kubrick's camera style, in which his studied production design and compositional symmetries are a method of enforcing control. It's the camera as superego. But the problem is that you don't feel any human presence behind the lens. As a result, the movie has a point of view -- that man is a killer and, in war, finds the ultimate expression of his true nature -- but no moral center.

The overcareful framing places the action in a kind of conceptual neutral zone. Even though some of the battle sequences have a certain end-of-the-world grandeur -- it's the apocalypse as Turner might have painted it -- his approach forces you to look but not feel. It's Vietnam as performance art. And ultimately it cancels itself out. The only residue is a sense of free-floating rancor and ugliness of spirit.

"Full Metal Jacket" and "Platoon" do have some things in common, though. Both stories are told in voice-over by an offscreen narrator; this, in fact, is a stylistic motif in almost all the films -- "Apocalypse," "Gardens of Stone," "The Boys in Company C" and others -- taking their cue from the first-person commentary in "The Red Badge of Courage."

The other affinity that emerges -- and, for that matter, emerges from almost all the films about Vietnam -- is the notion of the random, irrational nature of warfare. In previous wars, and in the movies made about them, there could be at least the illusion that war was an orderly, rational pursuit. And there was, at least for the generals in the field, a visible purpose to the deployment of troops -- a real enemy, a right side and a wrong side.

In Vietnam, there is no easily identifiable enemy, and the line between good and evil has become violently distorted and confused, open to interpretation. For this reason, an incident like the one in the 1980 Sam Fuller film, "The Big Red One," where Mark Hamill traps a Nazi soldier in one of the ovens at Buchenwald and shoots him, slowly, again and again and again, becomes an act of nostalgia, of longing for a less complicated time and clearer moral distinctions. The "Rambo" movies and a film like Clint Eastwood's "Heartbreak Ridge" express something perhaps even baser -- the hysteria for some kind of victory, for something in the win column, no matter how cheap.

Hollywood's one true contribution to the record is that, through its films about Vietnam, it carried war into the 20th century, the century of Freud and the unconscious. In "Go Tell the Spartans," a major, played by Burt Lancaster, asks his second in command, "Where are we, Alfred? I mean, geographically." "Vietnam, sir. Pa Nang," he answers. "You sure we aren't in a loony bin?" Lancaster asks. "Sometimes I get the feeling we're in a goddamned loony bin."

Vietnam was the crazy war, the war in which things broke down and soldiers did wild, unpredictable, sometimes monstrous things. In "Platoon" and "Apocalypse," the jungle itself becomes the force of the irrational, and what it expresses is the natural surrealism of the scene, the sense of ever-present, constantly threatening danger. In "Apocalypse Now," Robert Duvall leads a cavalry charge of choppers -- with Wagner's "Ride of the Valkyries" blasting over the speakers -- to reclaim a beachhead from Charlie simply because it has the best break of waves for surfing in Vietnam, and the scene with the soldiers riding their boards as shells fall all around them captures the sense of mad daring that practically sums up the trippy mood of the whole era.

The picture of the soldier in the Vietnam movies is different from that shown in other war films, too. The John Wayne character, so commanding in his World War II roles, becomes a dinosaur in "The Green Berets," a gung-ho Army clown, and he rings about as true as does the movie's final shot in which the sun sets into the South China Sea -- which faces east. (A fact that Gustav Hasford makes note of in his novel "The Short-Timers" on which "Full Metal Jacket" is based.)

The Vietnam of the movies was not a theater for heroism and glory as the movies from previous eras were. There have not been any "Sergeant Yorks" for Vietnam, although in its depiction of the courageous prisoners of war, "Hanoi Hilton" comes close.

Until "Platoon" and perhaps Springsteen's "Born in the U.S.A." video, there were no Vietnam war heroes on screen. Vietnam was an antiheroic war, and its heroes were troubled figures like Jon Voight and Bruce Dern in "Coming Home," or Christopher Walken and John Savage in "The Deer Hunter," or Martin Sheen in "Apocalypse." Antiheroes. But in "Platoon" the grunt hero was born. And with his emergence, the hero ethic was replaced by the survival ethic; the grunt's goal in the Vietnam of the movies was to stay alive, to stay in one piece, and anyone who managed it was heroic.

This is a far cry from a movie like "Patton," where the idea of the military model still holds true and the romanticized notion of the gentleman soldier and military scholar that comes down to us from films like "The Four Feathers" and "The Charge of the Light Brigrade" continues as a living ideal. The Robert De Niro character in "The Deer Hunter" is an attempt to forge a hero -- a modern-day Natty Bumppo -- along these conventional lines, but part of Cimino's point is that, in this context, a hero is an anachronism, a noble freak. Even his friends think he's weird.

Perhaps the two most potent modern military archetypes in film are George C. Scott's Patton and Marlon Brando's Col. Kurtz in "Apocalypse," both of whom were created, in part, by Francis Coppola. Patton epitomizes the Second World War and Kurtz Vietnam. But already in Patton we can see the fissure in the myth.

The cliche' is that soldiers treasure peace more devoutly than other men because it is they who, in time of war, must fight. But for Patton, war was his fulfilment, the medium of his genius, and he needed to realize and express himself. Tragedy for Patton came when he could no longer fight; peace was his downfall.

Brando's Kurtz is Patton taken to his logical extreme. Essentially, they're two sides of the same coin. But whereas Patton saw himself as belonging to a tradition stretching back to the Caesars and Alexander the Great, Kurtz has passed beyond tradition into a consciousness of the true, terrible burden of the soldier hero.

"Apocalypse Now" is Coppola's long, Conradian voyage into the dark heart of war, and what he finds at the end of his journey is Kurtz bunkered away in his temple headquarters. Kurtz is Coppola's symbol for the American experience in Vietnam. During one of Willard's meetings with him, Kurtz tells him a story about an incident some years back in which all the children in a village were given vaccination shots by the Americans. All had gone smoothly, the Americans assumed, until they returned to the scene and in the center of the village was a pile of tiny, severed arms. "I then I realized," Kurtz says, "like I was shot, like I was shot with a diamond, a diamond bullet right through the forehead. And I thought, my god, the genius of that, the genius ... the will to do that. Perfect, genuine, complete, crystalline, pure. And then I realized that they were stronger than we. Because they could stand it."

What makes Brando's Kurtz such a great, tragic character -- the single most compelling figure in the Vietnam war movies -- is that he is man, a model soldier, broken in two by the awareness that he cannot commit the sins that the war requires him to commit; that for a moral man to embrace murder and genocide, to have the strength to win against his enemies, is to embrace immorality and, therefore, to lose himself.

Kurtz longs for a life without moral distinctions, without judgment, "because it's judgment that defeats us." And the impossibilty of attaining what he desires leaves him fractured, deranged.

The overall picture that emerges from these movies is that of a similarly ravaged, splintered nation; it's a portrait of epic demoralization, and their tone is wounded, keening. Two great metaphorical images emerge from the war on film: the chopper and the body bag. And they continue to recur, in other movies and in the news, as reminders of the experience -- to loom symbolically and, to some degree, to haunt us.

One critic wrote that "Platoon" was a great movie for no other reason than it reclaimed the war for the left. But, though the writer has a point -- the war, it seems, was being appropriated and recast by Chuck Norris and Stallone and Eastwood and by Realpolitik stars as well -- I can't really agree. "Platoon" isn't a great movie. But it has a resonance far beyond anything Kubrick accomplishes in his film. And what the current emergence of the war on film signifies, perhaps, is the beginning of a new phase in the Vietnam experience -- the end of a period of mourning and the beginning of a real rehabilitation.