"Your right to swing your fist ends at my nose."

This is where law begins at end. Beyond this law has no purpose. This is also a non-negotiable absolute axiom contrary to what the commies say.(https://steemit.com/whales/@taskmaster4450/whales-and-others-their-behavior-on-full-display#@pandorasbox/re-vimukthi-re-pandorasbox-re-taskmaster4450-whales-and-others-their-behavior-on-full-display-20171221t182058406z)

I'm going to defend myself against your punch before it lands.

This is Justice. Justice is more or less pointless after the damage has been done. Prevention is better than cure. Any form of aggression that is used against a First breach of NAP (A crime) that doesn't far significantly exceed the original aggression is a non-crime though it's a sin. My definition includes First Degree Murder.