When the U.S. Supreme Court handed down Wal-Mart Stores, Inc. v. Dukes this summer, defense lawyers hailed it as a class action – killer. The blockbuster decision decertified a massive gender discrimination lawsuit against one of the nation’s largest private employers. And as predicted, many judges have relied on Dukes to dismiss class actions across the country. But plaintiffs lawyers have been able to limit the ruling’s impact in a number of cases.

Justice Antonin Scalia’s majority opinion clarified the rule of civil procedure requiring that class actions contain “questions of law or fact common to the class” — a past source of disagreement among lower court judges. Virtually every class action raises some conceivable issue common to all class members, the Court reasoned. The federal rules require something more: a common question that, if answered, will resolve, in “one stroke,” an issue “central to the validity of each one of the claims.”