In a criminal matter, what is the definition of an affirmative defense? In a criminal matter, what is the definition of an affirmative defense? The State met its burden of proof beyond a reasonable doubt but the defense put on evidence of that at the time of the offense, the defendant had a serious mental disorder which made the accused unable to appreciate the wrongfulness of her conduct. The State was able to prove a prima facie case but the defense affirmatively disproved the allegations. The State proved its case by a preponderance of the evidence but the defense's expert testified and defeated or mitigated the legal consequences of the defendant's otherwise unlawful conduct. Both A and C