Last year, the Ninth Circuit curtailed the use of Rule 12(f) motions to strike in a case of first impression called Whittlestone, Inc. v. Handi-Craft Co., 618 F.3d 970 (9th Cir. 2010). The narrow holding of Whittlestone is that "Rule 12(f) does not authorize district courts to strike claims for damages on the ground that such claims are precluded as a matter of law." Id. at 974-975. Rule 12(f) of the Federal Rules of Civil Procedure states that a district court "may strike from a pleading an insufficient defense or any redundant, immaterial, impertinent, or scandalous matter." "The function of a 12(f) motion to strike is to avoid the expenditure of time and money that must arise from litigating spurious issues by dispensing with those issues prior to trial . . . ." Fantasy, Inc. v. Fogerty, 984 F.2d 1524, 1527 (9th Cir. 1993) (overruled on other grounds in Fogerty v. Fantasy, Inc., 510 U.S. 517 (1994)).

Whittlestone was a breach of contract case where the defendant filed a motion to strike the plaintiff's claims for lost profits and consequential damages, arguing that the claims were barred under the contract. Id. at 973. The district court granted the motion to strike. Id. The Ninth Circuit reversed because courts "may not resolve disputed and substantial factual or legal issues in deciding a motion to strike." Id. (internal quotation marks and brackets omitted). Specifically, the court found that a claim for damages was not an insufficient defense, redundant, immaterial, impertinent, or scandalous matter. Id. at 974. Further, the court reasoned that reading "Rule 12(f) in a manner that allowed litigants to use it as a means to dismiss some or all of a pleading . . . would be creating redundancies within the Federal Rules of Civil Procedure, because a Rule 12(b)(6) motion . . . already serves such a purpose." Id. Additionally, the court reasoned that because Rule 12(f) motions are reviewed for abuse of discretion and Rule 12(b) (6) motions are reviewed de novo, it would not make sense to allow litigants to seek dismissal of a pleading under 12(f) when it could do so under Rule 12(b) (6). Id.