Self-defense (United States)
||This article needs attention from an expert in Law. (August 2013)|
|Part of the common law series|
|Other common law areas|
On a federal level, self defense is legal only in response to "An affirmative, unlawful act reasonably calculated to produce an affray foreboding injurious or fatal consequences." 
The definition of legal self defense on a state level often varies significantly from this definition and from other states, but each state makes an important distinction between the use of non-deadly and deadly force. A person may use non-deadly force to prevent imminent injury; however, a person may not use deadly force unless that person is in reasonable fear of serious injury or death. Some states also include a duty to retreat, when deadly force may only be used if the person is unable to safely retreat. A person is generally not obligated to retreat if in one's own home in what has been called the castle exception (from the expression "A man's home is his castle").
Runyan v. State (1877) 57 Ind. 80, 20 Am.Rep. 52, is one of the earliest cases to strongly support and establish in U.S. law an individual's right to initiate self-defense actions up to and including the justifiable use of lethal force against an aggressor.
In Runyan, the court stated "When a person, being without fault, is in a place where he has a right to be, is violently assaulted, he may, without retreating, repel by force, and if, in the reasonable exercise of his right of self defense, his assailant is killed, he is justiciable."
A related case is the U.S. Supreme Court case Bad Elk v. United States (1900) 177 U.S. 529, 44 L.Ed. 874, 20 S.Ct. 729, where an off-duty police officer was granted a new trial after being convicted of killing an on-duty police officer who was attempting to illegally arrest the man, because, at the initial trial, the jury was not instructed that it could convict on a lesser offense, such as manslaughter. Runyan v. State is further supported by additional cases such as Miller v. State (1881) 74 Ind. 1., Jones v. State (1888) 26 Tex.App. 1, 9 S.W. 53, 8 Am.St.Rep. 454, Beaverts v. State (1878) 4 Tex.App. 175, and Skidmore v. State (1875) 43 Tex. 93.
- Battered woman syndrome
- Castle Doctrine
- Deadly force
- Defense of property
- Imperfect self-defense
- Plummer v. State
- Right of self-defense
- Self-defence (Australia)
- Self-defence in English law
- Self-defense (Sweden)
- Stand-your-ground law
- Use of force
- Branca, Andrew. ["http://www.lawofselfdefense.com "The Law of Self Defense, 2nd Edition"]. lawofselfdefense.com. Retrieved 12 March 2014.
- Louisiana Criminal Code: Use of force or violence in defense, La. R.S. 14:19 . Justifiable homicide, La. R.S. 14:20 .
- Texas Penal Code: Chapter 9. Justification Excluding Criminal Responsibility, § 9.31/§ 9.44 .