Sam Green and Bill Siegel's The Weather Underground attempts to cover an awful lot of ground in 90 minutes: tracking the rise of the SDS (Students for a Democratic Society) from a non-violent civil rights group to America's largest radical leftist organization; explaining how a militant wing of the group first took control of the SDS and then splintered into a violent, revolutionary faction called The Weathermen; chronicling the group's declaration of war against the American government (and later the American people) as they attempted to "bring the war home" through a series of violent actions; and how the revolutionaries learned to "hide in plain sight" until most of them independently made the decision to give themselves up. That it does so as well as it does is remarkable, and if the film is flawed, it's in what isn't there rather than what is. For example, it seems odd that there's not a single mention of the 1968 Democratic National Convention in Chicago, where the aggressive side of the Left met one of their most bitter defeats at the hands of the police; and while a handful of former Weathermen speak of their years underground, most are cautiously hesitant to discuss the details of their lives in hiding or how they worked with other radical groups, which isn't difficult to understand, but still leaves a significant chunk of this story untold. Also, while one FBI agent goes on record to discuss how the bureau tracked the Weathermen's activities, we learn little of the covert actions of COINTELPRO, the notorious FBI task force created to ferret out political dissidents. (Its ruthless disregard for due process and the Bill of Rights eventually caused most of the court cases against the repentant Weathermen to be thrown out of court.) As a complete overview of one of the most fascinating and troubling chapters in the political history of Vietnam-era America, The Weather Underground misses the mark, but as an introduction, it's compelling and thought-provoking stuff. Green and Siegel allow their subjects to explain themselves and their actions with little interference and the various degrees of their three-decade hindsight is itself one of the most fascinating aspects of the film.