Just watched 'Red Storm Rising - The Struggle For The American Communist Party', on PBS. Despite the title, it's actually an interesting study of radical Left politics from the Nineteenth Century to the 1950's (Syndicalist/ Anarchist/ Communist/Socialist) - an often forgotten aspect of US political history. There is also the mix of the personal and the political, through the conflict between the Syndicalist, William Foster and the Communist, Earl Browder, and how their poilitcal views changed over time.
Even if you completely disagree with the politics, it's still a fascinating history. With a higher budget, and a little more 'polish', it might have been an 'American Experience' - a counterpoint to 'Nazi Town USA', which examined the radical Right up to the 1940's.