 He has long been interested in issues associated with the <unk> Act , which broke up the communal reservation lands and assigned plots to individual households . <unk> with that was the federal government 's first use of " blood quantum " to define individual membership in tribes , for what became known as the <unk> Rolls . Since re @-@ establishing self @-@ governments , <unk> recognized tribes have established their own criteria for enrollment as members , often related to descent from recognized historical lists , but less often requiring proofs of blood quantum . Some of his published works address these issues , which he has interpreted as part of the federal government 's policy of <unk> against Native Americans . 
