On March 27, 2013, the U.S. Supreme Court took what could be a landmark action. While the rest of the country’s eye were turned to the oral arguments that day on the constitutionality of DOMA in the case of United States v. Windsor, the Court took a less heralded but no less potentially-wide-reaching action, releasing its opinion regarding class certification requirements in Comcast Corp. v. Behrend, No. 11-864.

In class actions under Federal Rule of Civil Procedure 23(b)(3), to have their class certified before the merits of the case are ever tried, plaintiffs must show that issues common to the class as a whole predominate over issues of individual plaintiffs. In a 5-4 opinion, Justice Scalia delivered the opinion of the Court in Comcast, holding that even at this early pre-trial stage class plaintiffs must make a showing of the damages methodology applicable to measure damages to the whole class. The district court and the Third Circuit Court of Appeals had found that it was sufficient for plaintiffs to have made a showing that common issues predominated over individual issues in the liability case, without reviewing the merits of the proposed damages model. The Third Circuit had held that, otherwise, the class certification review would intrude on consideration of the merits that should instead take place at trial. 655 F.3d 182, 206-07 (3d Cir. 2011).

Relying on the opinion in Wal-Mart Stores, Inc. v. Dukes, 564 U.S. —, 131 S. Ct. 2541 (2011), Justice Scalia held that the class certification review will necessarily overlap with the underlying merits of the plaintiffs’ claims. Justice Scalia quoted the Federal Judicial Center’s Reference Manual on Scientific Evidence, that “[t]he first step in a damages study is the translation of the legal theory of the harmful event into an analysis of the economic impact of that event,” to hold that, without a review of the plausibility of the proposed damages model to provide a class-wide measure of the damages asserted in the liability claim, 23(b)(3) certification is inappropriate.

Writing in dissent, Justice Ginsburg attempted to hem in the reach of the majority’s opinion by noting that it “breaks no new ground on the standard for certifying a class action[.]” Justice Ginsburg expressed that the majority’s opinion was restricted to the facts before it, and that in general the predominance requirement could still be met by showing that common liability issues predominate “even if damages are not provable in the aggregate.”

In the end, Comcast is another step in the path the Court has been traveling in recent years with regard to addressing pleading and proof requirements at the early stage of litigation, before the merits are ever addressed at trial or even at the summary judgment stage, following in the footsteps of the Court’s opinions in Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007); Ashcroft v. Iqbal, 556 U.S. 662 (2009); and Wal-Mart Stores, Inc. v. Dukes, 564 U.S. —, 131 S. Ct. 2541 (2011). As seen in Justice Ginsburg’s dissent, the reach of this line of cases is still evolving, and lawyers need to continue to be vigilant to each step the Court takes on its path.