Justification: Self-Defense

Self-defense and defense of others are defenses to a charge of criminal conduct in which the defendant concedes the transgression of a norm or statute against violence, for example, assault or homicide, but maintains that under the circumstances the use of force was either not wrongful ( justification) or is wrongful, but it would be unfair to impose punishment (excuse). Either as a justification or as an excuse, the defendant is completely exonerated. In contrast, "imperfect" or "incomplete" self-defense, where a significant element of the defense is absent, mitigates or reduces the charge, for example, from murder to manslaughter.

That one's force is not aggressive but defensive in nature is a defense to criminal conduct in all fifty states and is recognized in nearly every jurisdiction in the world. The pervasiveness of this legal right has its root in a number of extralegal ideas. First, the use of protective force is considered a fundamental, inalienable right of natural law or morality. Second, the Old Testament demands, in the face of violence, that we take an "eye for an eye, a tooth for a tooth." Third, human psychology suggests that using force in self-defense embodies the instinctual and overwhelming impulse toward self-preservation. As the great English legal scholar William Blackstone put it, killing in self-defense embodies "the primary law of nature" (vol. iii, p. 3). Based on this principle of self-preservation, the philosopher Thomas Hobbes, in his rationale for the defense of duress, provides a persuasive account for the illogic of refusing valid claims of self-defense:

If a man by the terrour of present death, be compelled to doe a fact against the Law, he is totally Excused; because no Law can oblige a man to abandon his own preservation. And supposing such a Law were obligatory; yet a man would reason thus, If I doe it not, I die presently; if I doe it, I die afterwards; therefore by doing it, there is time of life gained. (Leviathan, chap. 27 (1651))

In other words, faced with certain present death at the hands of a villainous assailant or possible subsequent death from the state's executioner, the will to live inculcated in our human nature is so strong that it would be futile to criminalize self-defense. Though the inevitability and inalienability of self-defense is perhaps self-evident, and serves as a necessary adjunct to the other self-evident truths of the right to life and liberty, the right to self-defense is curiously not a constitutional right (Rowe v. DeBruyn, 17 F.3d 1047 (7th Cir. 1994)).