"Seeing Red," which opens today at the Inner Circle, is a remarkable documentary. It examines the lives of American communists, taking on one of the great taboos and finding not the bogyman, but the leftist next door -- feisty and endearing soldiers in their own war against oppression.

The filmmakers, Julia Reichert and Jim Klein, are products of American culture (Klein says his favorite TV program as a child was "I Led Three Lives"), which, in Herbert Philbrick's words, defined communists as "shrewd . . . dirty . . . godless . . . and murderous." Their approach is almost ingenuous, wide-eyed innocents confronting party followers with questions like "were you really agents of the Soviet Union?" (One long-time party leader, Dorothy Healey, says that no American communists were arrested as spies; those that were indicted were charged under the Smith Act.)

But the filmmakers, while they are frankly sympathetic, are neither naive nor dogmatic, and their movie is thoughtful and provocative. (It was nominated for an Academy Award last spring.) The first startling fact they remind us of is that 1 million Americans were members of the Communist Party between the 1930s and the 1950s. The party's death blow was not the McCarthy era, or the red-baiting of the House Committee on Un-American Activities, but the revelation by Nikita Khrushchev in 1956 that Joseph Stalin had been a homicidal despot. About 80 percent of the membership left the party between 1956 and 1958, the filmmakers report, disillusioned and betrayed.

But not -- if this film is an accurate indication -- resigned to the status quo. Most of these old lefties, now white-haired and wrinkled, are still active, demonstrating against muclear weapons, rallying senior citizens, still fighting. One wonders at times whether it is the act of protest or the subject that is more energizing, and certainly some -- like folk singer Pete Seeger, are a bit sanctimonious. But then there is tiny Rose Kryzak, one of the few still in the party and retired after working 50 years as an actuarial clerk, pictured at a rally urging fellow senior citizens to demand decent living conditions, barely able to reach the microphone but determined to be heard.

The filmmakers do not view the communists through rose-colored lenses, but the film is a bit soft when confronting the obvious flaws in the party -- which claimed to aim at democracy for all yet functioned in an undemocratic way, taking orders from anonymous high officials here and in Russia with blind obedience. Several of the former communists admit in retrospect that this was a mistake, that their cause was hurt by the paranoid secrecy and totalitarian rule under which they operated. "I really sincerely believe today that there is an extraordinary connection between ends and means," says Ruth Maguire, who now administers social service programs. "And I think that we could at one point say, 'Well as long as our objectives are all that great, we can do all these crappy little things on the way.' " Such admissions make the documentary more than a historical report, and more than a memoir.

The filmmakers are intent on limiting their film to the human stories of the functionaries behind an era of political history, and the way they skirt around pivotal events is sometimes frustrating. Julius and Ethel Rosenberg, executed as spies, are present only as a still photograph; the Korean War is not mentioned. Most effective is the juxtaposition of archival footage with contemporary interviews; or film of an early May Day parade down New York's Fifth Avenue, complete with proud mothers pushing baby carriages, floats, banners and cheering crowds contrasted with one in the late '40s when the poltical climate had changed, showing passers-by hooting in derision and throwing things at the marchers. Writer Carl Hirsch is shown choking up while reading letters to his wife written while he was covering a sharecroppers' strike in Missouri in 1939, interspersed with footage from that strike that vividly affirms the misery he described.

Hirsch is one of the few in the film who views his party membership as a youthful fling; most others are proud to have been part of what one calls "the broken-hearted generation." The idealism espoused by the others is both sad and chastening. They truly believed, as Bill Bailey puts it, that the revolution would come in five years. That they were flawed -- in their vision and their methods -- is not to take away from their efforts to make things better for the poor and powerless, as corny as it sounds.

Reichert and Klein talked to 400 people before settling on the 16 who appear in the film. Many refused to be interviewed, still worried about repercussions. One wonders about those who were cut for other reasons -- whether they were less sympathetic, or less articulate, or did not somehow fit the filmmakers' vision. The people whose lives are examined here are rightfully proud of themselves; as Seeger says, "It's better to have struggled and lost than never to have struggled." They believed that people can make a difference; and the film offers a timely and eloquent record of a special brand of American idealism. It should be seen.