Party registration is uninteresting at scale as it just determines whether someone is the left or right half of the bell curve. It doesn't tell you if they're i

Party registration is uninteresting at scale as it just determines whether someone is the left or right half of the bell curve. It doesn't tell you if they're in the fat part or the long tail or what issues they care deeply about. The feds are very interested in cataloging who does and doesn't have extremist views (the long tail). Militant commies, 3%ers, stuff like that. And once some bit of iconography is identified they can run a historical search to see who had it before it went mainstream enough for the feds to pick up on it. While it's fashionable to denigrate extremists pretty much every useful and/or positive political movement starts out there at some point.