Ann swings her arm and injures Ben. She faces moral condemnation and legal liability unless she can offer an explanation that absolves her of full blame. She might make a claim of justification that, despite initial appearances, her action was desirable or proper, or she might make a claim of excuse that she does not bear full responsibility for injuring Ben. If Ann is fully justified, she will not be subject to blame or to classification as a weak or defective person. If Ann is excused, she may be regarded as wholly or partly free of blame, but she will have demonstrated weakness or some defect. Because the moral evaluation of a justified actor differs from the moral evaluation of an excused actor, deciding whether Ann is justified or excused is an important moral question.
In the legal context, a defendant who successfully establishes the legal Analogue of a moral justification or excuse is typically relieved of liability. Because of the injury to Ben, it is likely that Ann will be prosecuted for assault, which is defined as "purposely, knowingly, or recklessly causing bodily injury to another." Nevertheless, Ann may offer an exonerating explanation that precludes satisfaction of the basic elements of the crime or that, conceding the presence of the basic elements, precludes liability on other grounds.
In modern American criminal law the terms "justification" and "excuse" only refer to the second kind of explanation – that is, they concede the presence of the basic elements but deny liability on independent grounds. If Ann acknowledges that she intentionally hit Ben but did so to prevent him from detonating a bomb, she offers a justification; if she says that she decided to hit him because she was insane, she offers an excuse.
There are other explanations that exonerate an actor from liability because they preclude satisfaction of the basic elements of a crime. These explanations are similar to justifications or excuses but are not labelled as such by the law. If Ann says she had to take the risk that her swinging arm would injure Ben in order to protect Carol from David's deadly attack, she effectively denies that her actions were reckless, since recklessness involves the conscious disregard of a substantial and unjustifiable risk. If Ann says she was flailing her arms for dramatic effect, unaware that Ben was standing close by, she denies the minimal culpability requirement of conscious risk-taking. In admitting clumsiness, Ann removes her actions from the ambit of assault. As J.L. Austin noted in A Plea for Excuses, "[when] I have broken your dish... maybe the best defense that I can find will be clumsiness." The second half of this article notes that many exonerating explanations that look like justifications and excuses concern the basic elements of offenses and explains why this fact bears strongly on the expectations one should have from the legal system in distinguishing justifications from excuses more narrowly understood.
Courts | Law
Distinguishing Justifications from Excuses,
Law & Contemp. Probs.
Available at: https://scholarship.law.columbia.edu/faculty_scholarship/3807