Also known as: affirmative defenses · affirmative defence
Written by attorneys · grounded in primary & secondary sources — see below
A defendant's assertion of facts and arguments that, if true, defeats the plaintiff's or prosecution's claim even if all allegations in the complaint are true. The defendant bears the burden of proving the affirmative defense.
Adrian Aguilar entered an empty warehouse at night intending to remove scrap metal. The structure had stood vacant for years with no utilities or security. At trial Aguilar proved the building was abandoned. The affirmative defense defeated the burglary charge.
Amber Alonzo sued a federal aide for alleged constitutional violations arising from an investigation. The aide answered and asserted qualified immunity as an affirmative defense. The court required the aide to plead and prove the defense before trial proceeded.
Select any source to read its text and confirm it supports the definition.
Andrew Avery sued a rural cooperative after suffering injury on a job site. The cooperative raised the statutory-employer defense in its answer. The trial court treated the defense as an affirmative defense that presented a factual question for the jury.
Anita Ali pleaded guilty to a firearms offense. The government sought an enhanced sentence based on a racial-bias finding. Ali argued the finding could not be treated as an affirmative defense that she must disprove. The court held the enhancement required jury proof beyond a reasonable doubt.
Albert Allen traded securities after receiving material nonpublic information. He faced criminal charges and argued lack of knowledge of the governing rule. The court recognized that lack of knowledge served as an affirmative defense to imprisonment but not to the underlying violation.
Amelia Amari sued the state of Maine in state court for overtime wages under federal law. Maine answered by asserting sovereign immunity as an affirmative defense. The court dismissed the action because the defense barred the suit in the state's own courts.
The defendant must prove the facts supporting an affirmative defense. Primary authorities allocate this burden to the defendant once the prosecution or plaintiff has established the elements of the claim.
A negative defense denies an element of the claim. An affirmative defense assumes the claim elements are true yet offers additional facts that defeat liability.
Yes. Federal Rule of Civil Procedure 8(c) and parallel state rules require a defendant to plead affirmative defenses or risk waiver. Failure to plead prevents later reliance on the defense at trial.
Yes. A state may place the burden of proving insanity or self-defense on the defendant provided the prosecution still proves every element of the offense beyond a reasonable doubt.
…the Government to prove "willful[l]violat[ion]" of the securities laws, and that lack of knowledge of the relevant rule is an affirmative defense to a sentence of imprisonment. See supra , at 665-666. [^maj-25]: The Court of Appeals reversed respondent's money laundering convictions on similar reasoning. See 92 F. 3d, at 628.…