In Comcast Corp. v. Behrend, 133 S. Ct. 1426 (2013), a 5-4 majority — over an extraordinary joint dissent by Justices Ginsburg and Breyer — had to work hard to make a modest ruling. The Court held that plaintiffs seeking class treatment under Rule 23(b)(3) sometimes may have to plausibly link their theory of liability (the misconduct that caused damages) to the theory of class-wide damages (the estimate of the damages flowing from the misconduct) in order to obtain class certification.
I say emphatically that the Court did not hold that any plaintiff class seeking certification under Rule 23(b)(3) must prove damages on a class-wide basis. It said only that if a class cannot obtain class certification without establishing class-wide damages, then by golly it must show that it can establish class-wide damages.
I should know; I briefed and argued the case for the plaintiff class.