Rule 8(c) establishes the requirement that all affirmative defenses be pleaded and establishes a non-exhaustive list of what defenses fall within the scope of that pleading requirement: In pleading to a preceding pleading, a party shall set forth affirmatively 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 limitations, waiver, and any other matter constituting an avoidance or affirmative defense. FED. R. CIV. P. 8(c) (emphasis added); see also Sayre v. Musicland Group, Inc., 850 F.2d 350, 353 (8th Cir. 1988) (noting that there are nineteen enumerated affirmative defenses, but that the list is 'non-exhaustive,' as it also includes 'any other matter constituting an avoidance or affirmative defense'); accord Brunswick Leasing Corp. v. Wisconsin Central, Ltd., 136 F.3d 521, 530 (7th Cir. 1998) ('Fed. R. Civ. P. 8(c) provides that 'a party shall set forth affirmatively [various enumerated defenses] and any other matter constituting an avoidance or affirmative defense,'' with emphasis supplied by that court). Thus, an affirmative defense within the meaning of Rule 8(c) must ''generally be pled or else [it] may ...