Many of John Sayles' films are about the oppression of the American working man by the man (Brother from Another Planet, Eight Men Out) and his broadly left-wing sensibilities suffuse all his work. It is funny that his best film (well in my opinion anyway) is literally about the oppression of the working class.
This is a fantastic movie - a terribly sad tale of a group of minors in Matewan, West Virginia in the 1920s as the struggle to unionise, fight for better pay and conditions. In fact the company is even more sinister: it owns their homes, it runs the only shop (they are not even paid in US dollars, they are paid in company scrip), effectively it owns them.
The main protagonist is the union representative sent into the town to help organise a strike. The film centres on him as it follows the story of strike through to the inevitable conclusion in violence and tragedy.
Almost every aspect of the film is close to perfection: the cinematography (presumably on a tiny budget) is beautiful and haunting, the story is well paced with a tangible feeling of authenticity and the cast is excellent. There is a real "sense of place" - I felt transported to West Virginia and into the lives of the strikers. This is not a simplistic film - it tackles complex subjects like justifiable violence and racism (when black workers are imported to break the strike) in an intelligent and thoughtful way.