An Overview of the
Doctrine of Self-Defense
UNDER TRADITIONAL SELF-DEFENSE DOCTRINE, also known as perfect self-defense, a defendant is justified in using a reasonable amount of force against another person if she honestly and reasonably believes that (1) she is in imminent or immediate danger of unlawful bodily harm from her aggressor, and (2) the use of such force is necessary to avoid the danger.1 Traditional self-defense doctrine requires necessity, imminence, and proportionality. Additionally, the threatened attack must be unlawful and the defendant must not have been the aggressor.
The first requirement is necessity. The defendant must honestly and reasonably believe that it is necessary to use force to protect against a threatened attack. This requirement seeks to ensure that people not use force against others unless and until it is really necessary to do so. The term necessity suggests that one has no choice but to use force to protect oneself. If less drastic alternatives are available, then the use of force to repel an attack is not truly necessary.
In keeping with the necessity requirement, early English common law required one who was being attacked to retreat until the wall was at his back before using deadly force in self-defense.2 In the United States, however, a person threatened with attack is not required to retreat before using nondeadly force to repel an attacker. In most states, a person is not even required to retreat before using deadly force to repel a threatened attack, even if a safe retreat is available? This no-retreat rule runs counter to the necessity requirement. If a safe retreat is available