What are affirmative defenses in a legal context?

Affirmative defenses serve as a response to a criminal accusation where the defendant admits to the act but introduces new evidence or arguments that justify or excuse the behavior, thereby mitigating liability. This approach shifts the focus from merely contesting whether the crime occurred to explaining the circumstances surrounding the act.

For instance, claims of self-defense or insanity are considered affirmative defenses. In self-defense, the defendant acknowledges that they caused harm but argues that their actions were necessary to prevent greater harm to themselves. In the case of insanity, the defendant accepts responsibility for the act but contends they were unable to understand the nature of the act or distinguish right from wrong at the time it occurred.

This differentiates affirmative defenses from other types of defenses, which may argue that the prosecution has not met its burden of proof or challenge the factual basis of the charge without admitting the act itself. Consequently, affirmative defenses can significantly alter the outcome of a case by justifying the conduct rather than denying or contesting it outright.