In Pari Delicto (Affirmative Defense)
In pari delicto is an affirmative defense to claims at law. The phrase literally means “in equal fault,” and is based on the principle that “when a participant in illegal, fraudulent, or inequitable conduct seeks to recover from another participant in that conduct, the parties are deemed in pari delicto, and the law will aid neither, but rather, will leave them where it finds them. Bushner v. Bushner, 307 P.2d 204 (Colo. 1957); Sender v. Kidder Peabody Co., Inc., 952 P.2d 779, 782 (Colo. App. 1997). That applies, of course, only to civil suits between parties - it isn't a defense to criminal charges brought by the state.
The defense of in pari delicto applies to claims for legal relief, whereas the otherwise similar affirmative defense of unclean hands applies only to claims for equitable relief. See, e.g., Hollander v. Zito, No. 11-cv-00499-MSK, 2011 WL 5834688, at *5 (D. Colo. Nov. 21, 2011). See our Litigation Checklist for the separation between legal and equitable claims.
The elements of the in pari delicto affirmative defense are:
(1) Plaintiff, as compared to the defendant, bears at least substantially equal responsibility for the wrong he seeks to redress; and
(2) Preclusion of the suit would not interfere with the purposes of the underlying law or otherwise contravene the public interest.
Bateman Eichler, Hill Richards, Inc. v. Berner, 472 U.S. 299, 310-11 (1985). While the Latin phrase in pari delicto means in “equal” fault, it is not actually a requirement to show that the purported wrongdoing of the plaintiff is in fact “mutual, simultaneous, and relatively equal” to that of the defendant. See, e.g., Peltz v. SHB Commodities, Inc., 115 F.3d 1082, 1090 (2d Cir. 1997).