SCENES from the Class Struggle in Portugal," the new documentary feature at the Whitney Museum of American Art, may be of more cinematic than political interest here, having been directed (with Philip Spinelli) by Robert Kramer, the young man who made two impressive fiction films ("Ice" and "The Edge") dealing with America's militant left in the late 1960's and early 70's. In Portugal, where nearly 50 years of a fascist dictatorship was over-thrown in 1974, Mr. Kramer found the sort of revolutionary struggle in progress that "Ice" and "The Edge" predict (so far, fruitlessly) for the United States. There was something extremely invigorating going in Portugal, but also—this film seems to say without being entirely aware of it—something that wasn't following the neat plans of the theoreticians. In Portugal, where the film is being distributed as a kind of teaching tool in factories, on farms and in neighborhoods, the title is "Will the Revolution Triumph?" The American title better describes the movie's content for those of us who aren't knowledgeable about the power blocs struggling for control in Portugal. It is a film of isolated scenes—interviews, newsreel footage, demonstrations, parades—all designed to present the case for one of the most militant of Portugal's political parties, the Proletarian Revolutionary Party, with no attempt to hide the film makers' biases. If one doesn't share the film makers' particular Marxist way of looking at the world, much of what the two narrators (one man, one woman) tell us is likely to be received with skepticism, though their analyses of Portugal's past seem sound enough. "Scenes from the Class Struggle" means to inform, not to entertain. Even so, it's a handsome film to look at, a collage of footage in color, in blackand-white and in monochromes. Its tone is meant to be as high and firm as the clenched fist of the Communist salute, but the final effect of the pictures we are shown is one of chaos, confusion, of people being polarized into political positions they don't even understand.