The legal use of force to defend yourself extends back to the beginning of human civilization. However, significant differences have arisen in different legal systems over how much force is justified and in what circumstances.
Modern-day Canada and the United States have some overlap in legal use of force for self-defence but differ significantly when it comes to the castle doctrine, a law adopted in some U.S. states allowing use of lethal force in protecting one’s home and, in some cases, property such as vehicles.
