An affirmative defense justifies exemption from or mitigation of liability when a defendant can prove facts that, under law, provide a legal excuse or justification for their otherwise tortious actions. Common examples include self-defense, consent, necessity, and statute of limitations. The court will consider these affirmative defenses within the context of statutory laws specific to that jurisdiction. For an affirmative defense to succeed, the burden is typically on the defendant to prove its applicability by preponderance of evidence.
For example: In a defamation case, truth can serve as an affirmative defense. If the defendant can show that the allegedly defamatory statements were true, they might be exempt from liability regardless of the harm caused.