There is some debate regarding whether 'failure to state a claim' may be raised as an affirmative defense or instead must be raised by separate motion. Compare, e.g., Instituto Nacional de Comercializacion Agricola v. Cont'l Ill. Nat'l Bank & Trust Co., 576 F. Supp. 985, 991 (N.D. Ill. 1983) (striking the affirmative defense of failure to state a claim because a true affirmative defense raises matters outside the plaintiff's complaint) with Codest Eng'g, 954 F. Supp. at 1231 (concluding that failure to state a claim may properly be asserted as an affirmative defense) and Fleet Bus. Credit Corp. v. Nat'l City Leasing Corp., 191 F.R.D. 568, 569 (N.D. Ill. 1999) (same). Notably, as one court has observed, although failure to state a claim may not meet the technical definition of an affirmative defense, Form 20 of the Federal Rules of Civil Procedure's Appendix of Forms lists 'failure to state a claim' as a model defense. See Builders Bank v. First Bank & Tr. Co. of Ill., 2004 U.S. Dist. LEXIS 5016, No. 03 C 4959, 2004 WL 626827 at *2 (N.D. Ill. Mar. 25, 2004). Rule 84 specifically authorizes the use of the model defenses ...