Sentence:  His narrative suggests that psychological factors shaped his decision to become a <WSD>Red Shirt</WSD>. Although his Republican father was murdered by Democrats in 1870, Fleming recalled being part of a<WSD> Red Shirt</WSD> group that killed the man in 1876. 
Meaning of the word marked with <WSD> tags:  A member of a paramilitary arm of the Democratic party in Mississippi and South Carolina at the end of Reconstruction.