The Illustrated Guide to Criminal Law
Chapter 15: It Was Either Him or Me
Self-Defense pg 15: Furball
As Arnold and Britt erupt in a cloud of fisticuffs, Eddie and the barmaid relax with their beers
BARMAID
I see Britt’s fighting back, now. Does that count as self-defense?
EDDIE
No, ma’am. Arnold was hitting him lawfully. You can only use force to protect yourself against unlawful attacks.
{SUGGESTED EDIT: Maybe state specifically that self-defense doesn’t justify hitting someone who was only protecting himself against you in the first place.]