Douglas Rushkoff Coercion
There's a chapter on rallies and demonstrations, specifically the Nazi ones for historical context, and a few white power ones he went to as part of his research.
As far as academics go, this guy is just amazing because he goes out and does the primary research himself, instead of being all sequestered in an ivory tower with his egg headiness.
Also, he does comic books in his spare time (and before you think that makes him worthless, Isaac Asimov actually worked as a chemistry professor, and SciFi writing was only a side thing till he was 40)