The Weather Underground leaves the viewer with many questions. To the filmmakers' credit, most of them are the right and urgent ones to ask.

Directors Sam Green and Bill Siegel expertly limn the forces that gave rise to Weatherman and clearly sympathize with the group's motivations. At the same time, they don't stint on Weatherman's follies.

Whose side the documentarians are on is never clear -- in a muddy rather than an ambiguous way. Did anyone die from the Weathermen's bombings? We don't find out here.

The most striking feature of the film ... is the banality of the political conceptions held by the members of the Weathermen and Weather Underground.