[JURIST] The US Supreme Court [official website; JURIST news archive] on Monday held [opinion, PDF] in Krupski v. Costa Crociere [Cornell LII backgrounder; JURIST report] that the appropriate application of "mistake" in Federal Rule of Civil Procedure 15(c)(1)(C) [text] is whether the party being added to the case knew or should have known about the dispute. The US Court of Appeals for the Eleventh Circuit held [opinion, PDF] that the rule does not apply to substitution of the correct defendant for a related corporation with a similar name where the plaintiff has imputed knowledge of the identity of the added defendant prior to filing suit. Counsel for the petitioner argued that the rule should apply when substituting the correct defendant. Justice Sonia Sotomayor, delivering the opinion of the court, reversed and remanded the Eleventh Circuit's ruling, holding that the text of the rule does not rely on plaintiff's knowledge in relating back:

Information in the plaintiff's possession is relevant only if it bears on the defendant understanding of whether the plaintiff made a mistake regarding the proper party identity. For purposes of that inquiry, it would be error to conflate knowledge of a party's existence with the absence of mistake. … That a plaintiff knows of a party's existence does not preclude her from making a mistake with respect to that party's identity.

Justice Antonin Scalia wrote a concurring opinion.

The court granted certiorari [JURIST report] in the case to resolve a circuit split over the definition of "mistake" within the rule. The petitioner in the case filed suit after suffering an injury on a cruise ship owned and operated by Costa Crociere S.p.A. (Costa Crociere). The petitioner's attorney originally filed suit against Costa Crociere's booking company Costa Cruise, N.V., LLC. After being notified of the mistake the petitioner filed an amended complaint against the correct party. The statute of limitations had run on Costa Crociere's liability, resulting in the need for rule 15(c)(1)(C).