Affirmative defense

An affirmative defense is a category of defense used in litigation between private parties in common law jurisdictions, or, more familiarly, a type of defense raised in criminal law by the defendant. Affirmative defense can be classified as either a justification defense or an excuse defense. [cite book|last=Brody|first=David C.|coauthors=James R. Acker, Wayne A. Logan|title=Criminal law|publisher=Aspen|date=2001|pages=p241|isbn=0834210835|url=,M1] A defendant affirms a criminal act is justified under certain circumstances that are presented, i.e. self defense, defense of others, defense of home/property. A defendant affirms a criminal act is excused due to a mental disease or defect at the time of the crime. Affirmative defenses operate to limit, excuse or avoid a defendant's criminal culpability or civil liability, even though the factual allegations of plaintiff's claim are admitted or proven.

A clear illustration of an affirmative defense is self-defense. [cite book|last=Neubauer|first=David W. |title=America's Courts and the Criminal Justice System|publisher=Wadsworth|date=2005|pages=p320|isbn=0534628923|url=,M1] In its simplest form, a criminal defendant may be exonerated, if he can demonstrate that he had an "honest" and "reasonable" belief that his conduct was necessary to protect himself or a third person against another's use of unlawful force.

Mistake of fact is another affirmative defense, usually used in combination with another, in which the defendant asserts that he reasonably believed the culpable act was necessary based on his observation, though given complete knowledge of the situation it is clear that the act was unwarranted. A person who assaults another person in defense of a third person that the victim had been attacking would be justified even if the victim and the third person were actors or performers, if the defendant could not reasonably have known this fact by observation.

Among the most controversial affirmative defenses is the insanity defense, [cite book|last=Neubauer|first=David W. |title=America's Courts and the Criminal Justice System|publisher=Wadsworth|date=2005|pages=p321|isbn=0534628923|url=] whereby a criminal defendant, shown to be insane at the time of their crime, seeks commitment to a mental institution in lieu of imprisonment.

Most affirmative defense must be timely plead by a defendant in order for the court to consider them, or else they are considered waived by the defendant's failure to assert them. The classic unwaivable affirmative defenses is lack of subject-matter jurisdiction. What constitutes timely assertion is often itself the subject of contentious litigation.

Because an affirmative defense requires an assertion of facts beyond those claimed by the plaintiff, generally the party making an affirmative defense bears the burden of proof. [cite book|last=Oran|first=Daniel |coauthors=Mark Tosti|title=Oran's Dictionary of the Law|publisher=Delmar|date=2000|pages=p20|isbn=0766817423|url=] The burden of proof is typically lower than beyond a reasonable doubt. It can either be proof by clear and convincing evidence or a preponderance of the evidence. In some cases or jurisdictions, however, the defense must only be asserted, and the prosecution has the burden of proving beyond a reasonable doubt that the defense is not applicable.

Rule 8 of the Federal Rules of Civil Procedure governs the assertion of affirmative defenses in civil cases filed in the United States district courts. Rule 8(c) specifically enumerates the following defenses: "accord and satisfaction, arbitration and award, assumption of risk, contributory negligence, discharge in bankruptcy, duress, estoppel, failure of consideration, fraud, illegality, injury by fellow servant, laches, license, payment, release, res judicata, statute of frauds, statute of limitations, waiver, and any other matter constituting an avoidance or affirmative defense."


* civil law
** Accord and satisfaction
** assumption of risk (when the plaintiff knowingly entered into a dangerous situation)
** authority
** consent
** defense of property
** duress
** estoppel
** contract-specification defense
** contractual provision (when the defendant's liability for causing the plaintiff's injuries had been waived in the contract)
** contributory negligence (when the plaintiff's actions contributed to his own injury)
** fair use
** laches (similar to statute of limitations)
** merger doctrine
** repossession
** statute of frauds
** statute of limitations (too much time has elapsed between the tort and the bringing of the suit)
** waiver
* criminal law
** insanity defense
** necessity
** self-defense
** statute of limitations
** Truth

ee also

* Reverse onus


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Look at other dictionaries:

  • affirmative defense — see defense 2a Merriam Webster’s Dictionary of Law. Merriam Webster. 1996. affirmative defense …   Law dictionary

  • affirmative defense — In pleading, matter asserted by defendant which, assuming the complaint to be true, constitutes a defense to it. A response to a plaintiffs claim which attacks the plaintiffs legal right to bring an action, as opposed to attacking the truth of… …   Black's law dictionary

  • affirmative defense — A defense which amounts to something more than a mere denial of the plaintiff s allegations; a defense which sets up new matter not embraced within the ordinary scope of a denial of the material averments of the complaint. Among such defenses are …   Ballentine's law dictionary

  • affirmative defense — noun : a defense setting up new matter that provides a defense against the plaintiff s case, assuming the complaint to be true …   Useful english dictionary

  • affirmative defense — noun A defense against a suit or criminal charge that asserts mitigating facts rather than contesting the main fact of the allegation …   Wiktionary

  • defense — de·fense /di fens, dē ˌfens/ n 1: the act or action of defending see also self defense 2 a: the theory or ground that forms the basis for a defendant s opposition to an allegation in a complaint or to a charge in a charging instrument (as an… …   Law dictionary

  • affirmative — af·fir·ma·tive /ə fər mə tiv/ adj 1: asserting the existence of certain facts esp. in support of a cause of action affirmative proof 2: resulting from an intentional act affirmative concealment 3: involving or requiring application of effort …   Law dictionary

  • defense of property — Affirmative defense in criminal law or tort law where force was used to protect one s property. Short Dictionary of (mostly American) Legal Terms and Abbreviations …   Law dictionary

  • defense of property — Affirmative defense in criminal case consisting of justified force in protecting one s property though such force must be reasonable under all circumstances …   Black's law dictionary

  • defense — That which is offered and alleged by the party proceeded against in an action or suit, as a reason in law or fact why the plaintiff should not recover or establish what he seeks. That which is put forward to diminish plaintiffs cause of action or …   Black's law dictionary

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