What are "affirmative defenses" in civil procedure?

Affirmative defenses are legal arguments made by a defendant that, if proven, can negate or reduce liability even if the claims made against them are true. This means that the defendant acknowledges that the factual elements of the plaintiff's claim might hold, yet introduces additional facts or legal justifications that should prevent a judgment in the plaintiff's favor. For example, a defendant might argue self-defense in a claim of assault, indicating that while the incident occurred, their actions were justified and therefore not liable for the harm caused.

This concept is central to civil procedure because it allows defendants to proactively present a defense that may lead to dismissal of the claim or mitigate potential damages. In contrast, the other options refer to different legal concepts that do not align with the definition of affirmative defenses. Arguments supporting a defendant's liability focus on reasons for the defendant being liable instead of negating it, procedures for submitting evidence pertain to how evidence is handled in court, and types of damages refer specifically to the remedies sought by a plaintiff rather than the defenses invoked by a defendant.