This is a 1941 recording of "Which Side Are You On?", performed by the Almanac Singers.
"Which Side Are You On?" was written in 1931 by Florence Reece, the wife of a union organizer for the United Mine Workers (UMW) in Harlan County, Kentucky.
In 1931, the miners and the mine owners of that region were locked in a violent struggle (Harlan County War). In an attempt to intimidate the Reece family, Sheriff J. H. Blair and his men (hired by the mining company) illegally entered their family home in search of Florence's husband. Florence and their children were terrorized by the experience.
Harlan County War
Pete Seeger played the banjo and sang this song. Seems like an odd omission from the description.
Didn't know this version. It's hauntingly good. Thanks!