Waging what most of the populace regards as pointless and unnecessary wars in the Middle East for more than 10 years now, the nation presumably receives some dubious comfort, perhaps even absolution, from official reports of the heroism of its all-volunteer military. Such accounts would probably provide more consolation if they had not been robbed of meaning by the disgusting media distortions of the Jessica Lynch "rescue" or the fraudulence of the Pentagon's treatment of Pat Tillman's death in Afghanistan. Whatever the validity of the cause, however, courage remains the true coin of service, a rare and precious resource spent profligately by politicians who exact it from the young.

The latest cinematic exploration of the work of the military, "Act of Valor," graphically demonstrates the actions of a platoon of special-operations troops in a series of connected combat situations. One of the movie's singular distinctions, trumpeted by the publicity people, involves its cast of fighters, not actors but actual active-duty Navy SEALs. Along with the director's technique, that cast obviously gives the film a powerful sense of authenticity.

From beginning to end "Act of Valor" proceeds very much like a documentary, concentrating heavily on a subject that American cinema generally handles better than anyone else, sheer mechanical process. Whenever the location changes - and it jumps abruptly from San Diego to the Philippines to Somalia to Mexico to Costa Rica and so forth - the screen shows a satellite map of the particular place, with a window in one corner enumerating longitude and latitude, and even the local temperature.

The director also employs a great many sequences using a hand-held camera, often with subjective shots from the point of view of various members of the SEALs, in effect embedding the viewer inside the platoon, moving with the fighters, chasing enemies, peering through their night-vision goggles, looking through their gun sights, aiming their weapons, dodging bullets and grenades. The immediacy of the technique continues the documentary feel of the film and suggests not only the confusion and chaos of armed combat, but also something of its excitement and even exhilaration.

The major plot of the film begins with two intercut sequences, showing two very different vehicles, an ice-cream truck and a Mercedes limousine, traveling through the streets of Manila. They both meet on the campus of an American school, where the students crowd around the truck to buy ice cream and the limo brings the American ambassador to pick up his son. The truck driver scurries away, while his assistant detonates a suicide bomb, an act that launches all the combat operations and bloodshed of the movie.

As the movie shifts around from place to place, it reveals a collaboration between two villains, one an Islamic terrorist, Abu Shabat (Jason Cottle), and the other a drug kingpin, Christo (Alex Veadov). The first major operation of the SEAL team requires them to rescue a CIA agent, Lisa Morales (Roselyn Sanchez), from Christo's heavily guarded compound in Central America, where she is being tortured. That mission depends on an immensely complicated coordination of advanced technology, involving computers, satellite communication, a drone launched like a model airplane, parachute jumps, helicopters, swift boats, and good old pick-up trucks; violent and terrifically exciting, it sets the tone for all the other firefights that follow.

The climactic action occurs in Mexico, where the SEALs must prevent Christo's men, assisted by a powerful drug cartel, from smuggling a group of Shabat's terrorists across the border, where they will deploy to various major cities and blow up themselves and everything near them with special explosive vests. The designer of the vests, whose wearers pass through security gates undetected, promises that their explosions will make 9/11 look like child's play.

"Act of Valor" works extremely well on a technical level, providing a convincingly authentic representation of an elite force that has accomplished a number of remarkably successful missions, including most spectacularly, the assassination of Osama Bin Laden. At the same time, perhaps unavoidably, it falls into the stereotypical patterns and even the self-regarding sentimentality of so many war movies. The film ultimately works best as an exciting full-length recruiting poster for the SEALs, who will undoubtedly find their pool of applicants expanding exponentially.