FOUR DAYS IN SEPTEMBER (O Que E Isso, Companheiro?) (Brazil, 1997) *** 1/2

It is based on facts, which have been minimally given the cosmetic treatment that invariably goes with adaptations from reportages to movies, with their spectacular "Oh, wow!" additions or their simplified Good Guys, Bad Guys morality.

The general background lies in the agitated history of Brazil with its autocratic governments. The immediate background is that of a succession of military governments which, since 1964, had suspended constitutional guarantees, civil rights, and the freedom of the press.

Demonstrations, as usual led by students, were numerous but ineffective. The film opens with excellent fake documentary riot footage, in black and white. Cut to July 20, 1969. Some young friends (among them a former seminarist and an actor) are watching on television astronaut Neil Armstrong (in the Apollo 11 mission) step out of the lunar module "The Eagle" and onto the surface of the moon.

There is no uniformity in that small group's politics, except a desire for democracy. One of the men is knee-jerkily anti-US and pro-Soviet; another proposes drastic revolutionary action; the actor is skeptical about the use of violence in the resistance.

Soon, some of them and others join a tiny group, MR8, the October 8 Revolutionary Movement. Led by Maria (a pseudonym), the new members are given noms-de-guerre, trained in pistol-shooting and other matters.

Their first operation is the robbing of a bank (aka liberating funds for the good fight), which succeeds, but at the expense of one of the men who hesitates to shoot (a no-no in terrorist handbooks) is shot, wounded, caught and tortured.

"Paulo," the middle-class intellectual among them, is a dud with guns but skilled in political oratory. It is crucial that the voice and the acts of the opposition to the government be widely known. But since censorship muzzles the press and other media, only a flamboyant act and its resulting headlines can break through nationally and internationally, call the world's attention to Brazil. Paulo comes up with that act : the abduction of American Ambassador Charles Elbrick.

This is done, the guerillas get their publicity, announce a short, un-postponable deadline for the release of the Ambassador in exchange of some 15 political prisoners. Otherwise, Mr. Elbrick will die.

What develops is a story known to many Brazilians but few North Americans. I will only reveal some of its aspects. For instance, one of the group, the pretty young blonde "Renee," under false pretenses manages to seduce the Ambassador's Chief of Security. The movie, in its economical fashion, shows neither the actual sex scene (which is painful enough to imagine without having to see it) nor the information that Renee obtains. Instead, the action goes directly to the results.

Mr. Elbrick is taken to a safe-house. It turns out to be not all that safe. That's an important, typical point. The kidnappers are idealists all right, but when it comes to underground skills, they're still wet behind the ears. Their leadership changes when two older men, respectively veterans of the Spanish Civil War and of terrorism in Sao Paolo, arrive to take over from Maria. Yet even then the operation is woefully unprofessional --with a major exception: the very clever way in which the ambassador is finally returned to freedom.

Add to this the enormous psychological burden on the young people who had really not thought through the horror of having, perhaps, to execute a human being. This is made even more painful as Ambassador Elbrick, held in a small room (where either he or his captors have to be blindfolded) forms a sort of bond with Paulo and Renee, a bond reinforced by Elbrick's quiet but sincere disapproval of any government's repressive measures.

To its credit, "Four Days" is structured in ways that are un-sensational, un-theatrical, un-heroic, un-romantic, un-sentimental and un-corny. Yet it contains many moments of edge-of-your-seat tension and suspense. And it has "State of Siege" written all over it.

"State of Siege" is a 1973 French film by the master of political "thinking thrillers," Greek-born Costa-Gavras, famous for "Z," "The Confession," and "Missing," among others. It too was the retelling of a true case. In 1970 Uruguay, Tupamaro guerillas kidnapped and executed Dan Mitrione, an American agent of AID, the Agency for International Development. He was accused of using it as a front and being in reality a CIA operative who taught repression and torture to South American authorities in more than one country.

"Four Days" keeps recalling and paralleling "State of Siege" in dozens of ways over and above the subject: from the same tactics in abducting an official from his limousine, to the discussions between the guerillas and their prisoner. Those, however, are inevitable aspects of such situations. The comparison is more interesting in the details where the two movies differ.

Whereas Costa-Gavras can create sweeping, dramatic visual moods, director Barreto ("Dona Flor and her Two Husbands")sticks to a straight quasi-documentary line, with ample use of original TV newsreel footage, whether of politics, Brazil's Independence Day, or a football game -- all worked well into the plot. Still, those are relatively minor technicals aspects.

Where "State of Siege" and "Four Days" part company is that the former was clearly an indictment of the U.S.A. and the dark side of some of its foreign policies, while there's not anti-Yankee agit-prop in the latter, where the culprit is the militarist Brazilian government. In "SOS" Mitrione (called Santore, played by Yves Montand) is presented as clearly guilty, though he looks neither ev il nor kind. Here, Elbrick is played by Alan Arkin as an most likable and decent being. He speaks fluent Portuguese. He does not have a great deal of screen time, yet he under-acts so splendidly that his restraint becomes eloquent and his character memorable.

Dialectics in "Four Days" are much less stressed than in "SOS." The Tupamaros are infinitely more professional than the MR8 group, the latter often reaching high levels of amateurish ineptitude.

Even so, the Brazilian movie maintains its natural, credible rhythm. It uses skilfully its rapid editing from one scene to another and cuts out non-vital sections. The differences among most of the characters (the hardened pro, the young types in search of romantic adventure, the true believers, etc.) are sketched briefly but sharply.

Given its subject, this may sound odd, but "Four Days" is a subtle work. Several events (invented or not) are extremely effective. We hear Elbrick writing a letter to his wife, but it is an imaginary letter of his thoughts that describe his mental and physical state, some of his captors, his reactions to them.

Better yet. An alarm rings.Two panicky captors appear in Elbrick's room, without their masks. Cut to Elbrick sitting on the toilet, looking desperate. Why? He is in greater danger than before since he has seen faces. A masterful bit.

When there comes a scene of love-making, born of despair as much as attraction, between Paulo and Maria, the act itself is not shown. It is no cliche either, since circumstances like those of the guerrillas easily engender such relationships. The film is overall free of cliches, artificial humor, moralizing, preaching or simplifications. The theoretical, pragmatic, ideological problems of the Resistance, and above all the problems of conscience among simpatico (mostly) idealists who may have to fight violence by killing an innocent, come through well, without needless rhetoric.

I found just one semi-goof. Ambassador Elbrick, a chic, fastidious dresser, in one of those surreal moments of a talk with Paulo, speaks of his man in Lisbon, the tailor who has been making elegant suits for him for fifteen years. Yet, the morning of his abduction, we see Elbrick get out of his ambassadorial bed and dress without taking a shower. Most unlikely, but then perhaps the only unlikely bit in a very convincing film.