by Roger Chartier:
Defense of Habitation also known as the Castle Doctrine is the Castle Law.
As far as it being a law, each state determines it's own legal definition and their own version by their own state laws. This is not a federal law but a general basis that has been sometimes adapted to create each state's version.
This idea of the law justifies a person whose home is under attack, to use force upon the attacker.
This concept is based on the English Common Law provision that "a man's home is his castle" and the law first derived from "The Institutes of the Laws of England" in the year 1628.
You would need protection during a home invasion.
The argument is that the occupant is justified in using deadly force in defending their place of residence, as well as defending any innocent occupants legally inside it, from violence or from an intrusion that may lead to violence.
It is often stated: "When a victim reasonably fears imminent peril of death or serious bodily harm to himself or another"
If someone breaks into your house and threatens you or your family's safety and you feel that you or the family member might be killed, you can kill them first if the law of your state says so. You had better be right though. Remember, each state has different laws, and this is just a general statement about the concept of the law.
Sometimes this is called defense of premises and has been interpreted to mean a vehicle, place of work, etc as well in some cases in some states.
Interpretation of this doctrine or defense varies from state to state as each state has its own Castle laws and each state differs in the specific instances to which the Castle Doctrine applies.
Different state versions of the law address the degree of retreat or resistance required before deadly force is permissible. Each states version has their own specific conditions, before a person who kills an intruder can use the defense.
You might remember the Clint Eastwood phrase
"Go ahead make my day"
Some of Colorado's lawmakers want to expand the Colorado "Make My Day" law -- which says people who use deadly force to protect themselves in their homes can't be prosecuted. A proposal would protect people who use deadly force to protect themselves in their businesses and automobiles.