From Tyco Fire Prods. v. Victaulic Co., 2011 U.S. Dist. LEXIS 40012 (E.D. Pa. April 13, 2011):

Plaintiff asks the Court to strike the affirmative defense to that effect under Federal Rule of Civil Procedure 12(f), and to dismiss the corresponding counterclaim pursuant to Rule 12(b)(6). ***

Plaintiff's motion is governed by Rules 12(b)(6) and 12(f). The former provides a basis by which a party may challenge the sufficiency of a counterclaim, see Fed. R. Civ. P. 12(b)(6) (stating that "failure to state a claim upon which relief can be granted" is a defense to a claim for relief), while the latter permits parties to challenge the sufficiency of an affirmative defense, see Fed. R. Civ. P. 12(f) (stating that the court "may strike from a pleading an insufficient defense"). Although both procedural devices are concerned with a pleading's legal sufficiency, the requirements underlying the sufficiency determination stem from different sources: Rule 8(a) applies to claims (and therefore counterclaims and crossclaims), while Rule 8(c) sets forth the standard for affirmative defenses. ***

Both rules, however, share a common purpose. Indeed, so-called "notice pleading" has always been the hallmark of Rules 8(a) and 8(c), which ultimately function to provide the opponent with notice of the claim or defense pled. *** Rule 12(b) provides a means of enforcing this policy goal. ***

In evaluating pleadings for legal sufficiency under Rules 12(b)(6) and 12(f), courts historically applied Conley's "no set of facts" test whereby the pleading in question would survive a challenge unless there was no set of facts under which the pleader could prevail.***

However, notwithstanding that Rule 12(e) provides a basis for remedying deficient notice and does not permit dismissal, the notion that a pleading should provide notice was often merged into the inquiry for assessing legal sufficiency by way of a motion to dismiss or strike. *** In doing so, courts fixed the quantum of notice required by reference to the complexity of the facts and legal theory alleged. *** Indeed, as this Court put it in summarizing what a plaintiff had to allege to survive a defendant's motion to dismiss, "the more substantively complex the cause of action, the greater the mandate for detail under [Rule 8(a)]."***

The Supreme Court's decisions in Twombly and Iqbal, both of which expressly and closely tied the concept of notice to a claim's legal sufficiency, have drastically reshaped these principles. In dispensing with Conley's "no set of facts" test, the Twombly Court held that a complaint's factual allegations must "be enough to raise a right to relief above the speculative level." ***

2. Split in Authority on Twombly-Iqbal's Applicability to Affirmative Defenses

Whether Twombly's "plausibility" standard applies to affirmative defenses, however, is far from settled. See Dann, 2011 WL 487207, at *4 ("District courts across the country have disagreed as to whether Twombly's plausibility standard has raised the bar for affirmative defenses."); see also Arthur R. Miller, From Conley to Twombly to Iqbal: A Double Play on the Federal Rules of Civil Procedure, 60 Duke L.J. 1, 101 n.391 (2010) (identifying and interpreting the split). As Judge Brody recently observed, the "majority of courts have held that Twombly's plausibility standard does apply to affirmative defenses" by "interpret[ing] Twombly as applying to all pleadings." Dann, 2011 WL 487207, at *4 n.6.

But many courts have persuasively argued that Twombly and Iqbal do not apply to affirmative defenses. In Charleswell v. Chase Manhattan Bank, N.A., for example, Judge DuBois distinguished Rule 8(a) from Rule 8(c), noting that Rule 8(a) requires a "statement of the claim showing that the pleader is entitled to relief" while Rule 8(c) only requires a pleader to "state" an affirmative defense. No. 01-119, 2009 WL 4981730, at *4 (D.V.I. Dec. 8, 2009) (emphasis added). Because the Twombly Court had interpreted Rule 8(a) and not Rule 8(c), Judge DuBois concluded "that the pleading standards articulated in Twombly and Iqbal do not extend to affirmative defenses." Id. at *4.

Pointing to the textual distinction Judge DuBois identified as well as other considerations, Judge Simandle recently reached the same conclusion. See Fed. Trade Comm'n v. Hope Now Modifications, LLC, 09-1204, 2011 WL 883202, at *2 (D.N.J. Mar. 10, 2011). ***

In light of the differences between Rules 8(a) and 8(c) in text and purpose, the Court concludes that Twombly and Iqbal do not apply to affirmative defenses. An affirmative defense need not be plausible to survive; it must merely provide fair notice of the issue involved. *** This, as the undetailed recitations of affirmative defenses illustrated in Form 30 show, is not an exacting standard even remotely approaching the type of notice required of a claim under Twombly and Iqbal. See Fed. R. Civ. P., App. of Forms, Form 30 ("The plaintiff's claim is barred by the statute of limitations because it arose more than years before this action was commenced."); id. ("The complaint fails to state a claim upon which relief can be granted.").

See also our blog entry of April 8, 2011 (applying Twiqbal to affirmative defenses.)