whether Congress should authorize over-filing, but, rather, whether Congress did authorize it. 6 . The EPA argues that LTV waived the affirmative defense of res judicata because it did not raise it in its answer to the complaint. See Phelps v. McClellan, 30 F.3d 658 (6th Cir.1994) ("Generally, a failure to plead an affirmative defense ... results in the waiver of that defense and its exclusion from the case.”). Because the EPA was not prejudiced by LTV’s decision to raise this affirmative defense for the first time in its motion for summary judgment, however, as evidenced by the EPA’s successful argument against the application of that doctrine here, the Court declines to find that LTV waived this defense. See e.g. Moore, Owen, Thomas & Co. v. Coffey, 992 F.2d 1439, 1445 (6th Cir.1993) (<HOLDING>). 7 . In United States v. ITT Rayonier; 627
holding that the defendants waived their affirmative defense of unenforceability by failing to raise the defense in response to the plaintiffs motion for summary judgment which the trial court granted holding that fair use is an affirmative defense holding that the government did not waive an affirmative defense not pleaded in the answer because it raised the defense at a pragmatically sufficient time by listing the defense in the joint pretrial order holding that defendants failure to assert the defense in any pretrial motions did not waive defendants limitations defense because the assertion of a limitations defense in the answer preserved defendants right to raise the defense both during the first trial and before the second holding that defendant does not waive an affirmative defense if defendant raises it at a pragmatically sufficient time such as summary judgment and the defendants failure raise the affirmative defense in its answer did not cause the plaintiff prejudice