Because an affirmative defense requires an assertion of facts beyond those claimed by the plaintiff, generally the party who offers an affirmative defense bears the
burden of proof.
[6] The standard of proof is typically lower than
beyond a reasonable doubt. It can either be proved by
clear and convincing evidence or by a
preponderance of the evidence. In some cases or jurisdictions, however, the defense must only be asserted, and the prosecution has the burden to prove beyond a reasonable doubt that the defense is not applicable.[
citation needed]