Confirming the pattern of 2011’s Wal-Mart v. Dukes, the issue of class action procedure continues to generate a sharp 5–4 ideological split at the Supreme Court. On Wednesday, replicating the general Dukes line-up, the Court’s five conservatives ruled against certifying a large antitrust class action against Comcast over its conduct in the Philadelphia cable market, finding that the plaintiffs’ model of economic damages did not suffice to justify handling the case as a class action. (The trial court had knocked out three of the plaintiffs’ four theories of recovery; the majority found the plaintiffs’ economic model did not distinguish among the theories in such a way as to enable a court to recognize distinct damages attributable to the surviving theory.)


Despite protest from a few pro-antitrust commentators and sweeping claims of victory by a few on the defense side, Comcast is most likely to be remembered as a relatively narrow ruling with limited impact on future cases, for reasons Andrew Longstreth explains at Reuters. Some plaintiffs will need to be a bit more careful in constructing their cases, but the differences won’t be major. Indeed, the dissenters, led by Justices Ruth Ginsburg and Stephen Breyer, describe the majority’s ruling as “good for this day and case only.”


The Cato Institute had entered the fray with an amicus brief arguing the following:

  1. Courts must engage in a rigorous analysis at the certification stage rather than wave plaintiffs through the gate, even when such an inquiry overlaps with questions of merits that go to the case’s ultimate substantive resolution.
  2. In particular, expert reports at the certification stage should be subject to Daubert tests of admissibility, as they are at the merits stage.

The majority opinion emphatically agreed with us on the first point and the dissent did not make any real attempt to challenge it. That suggests that a sound view of this question may command a broad or even unanimous consensus on the Court.


To many participants’ surprise, the Court never reached the second point about admissibility, instead proceeding to rule on questions of predominance. This led to a sharp protest from the four dissenters that the majority was reaching out to decide the case on a different ground than it had been briefed on.


Few doubt that we can expect more wrangling at the Court on class action standards. That could soon happen in its consideration of a Sixth Circuit washing-machine case called Whirlpool v. Glazer, discussed by Ted Frank here.