Refer to these SCOTUS decisions...
Brown v. United States
"Brown v. United States, [1] was a United States Supreme Court case where the Court held that if a person is attacked, and that person reasonably believes that he is in immediate danger of death or grievous bodily injury, he has no duty to retreat and may stand his ground and, if he kills his attacker, he has not exceeded the bounds of lawful self-defense."
Brown v. United States (1921) - Wikipedia, the free encyclopedia
District of Columbia v. Heller
"District of Columbia v. Heller, 554 U.S. 570 (2008), was a landmark case in which the Supreme Court of the United States held in a 5-4 decision that the Second Amendment to the United States Constitution applies to federal enclaves and protects an individual's right to possess a firearm for traditionally lawful purposes, such as self-defense within the home. The decision did not address the question of whether the Second Amendment extends beyond federal enclaves to the states,[1] which was addressed later by McDonald v. Chicago (2010). It was the first Supreme Court case to decide whether the Second Amendment protects an individual right to keep and bear arms for self-defense.[2]"
District of Columbia v. Heller - Wikipedia, the free encyclopedia