In the early '70s, the radically enraged, bomb-planting fringe group known as the Weathermen had the doomed distinction of being as alienated from the antiwar counterculture as the counterculture was from the rest of America. The group planned to blow up empty buildings, but on March 6, 1970, an explosive went off by accident on West 11th Street in New York's Greenwich Village, killing three of the Weathermen's members and turning the rest of them into outlaws on the run. Three decades hence, you might assume that their descent into cultish mayhem hasn't aged well, but the achievement of The Weather Underground, a powerful and searching documentary, is how fully it enmeshes us in the madness, the devotion, the myopic absolutism, and -- yes -- the fearlessness of the Vietnam era's most righteous anarchists without making any false pleas that we sign on to their vision.
Meditating, in hindsight, on their actions, the former Weathermen, notably Mark Rudd and Bernadine Dohrn, are thoughtful and moving in their middle-aged circumspection. Years after turning themselves in, they usher us back to a moment when protest had become a kind of narcotic, and the dosage was ready to be upped. In 1969, they hijacked the annual convention of Students for a Democratic Society and set forth their extremist agenda: to attack the violence of Vietnam with more violence. The deeply personal roots of the Weathermen's struggle are revealed in the bizarrely funny tale of the Days of Rage, a ''mass'' protest-in-the-park that shocked them into action precisely because it attracted a mere 150 people. Was this a revolution -- or the ultimate motivating ego blow? Mark Rudd, who now looks like a melancholy teddy bear, says, ''I cherished my anger as a badge of moral superiority.'' ''The Weather Underground'' reveals the deep danger of that stance, and also its ambiguous fervor.