Abstract: A class action can only bind class members who are “adequately represented,” and thus a class action court necessarily determines representational adequacy. But should class members who were not an active part of that proceeding be able to relitigate adequacy in a collateral forum at a later date so as to evade the binding effect of the class judgment? Courts and scholars have generated a bipolar response to that question, with one side arguing that full relitigation is required by the constitutional nature of the question and the other insisting that no relitigation is permitted because of the issue-preclusive effect of the class court’s holding. Despite the richness of this debate, myriad specific questions about the availability, substance, and procedural details of the relitigation opportunity remain unexamined. In this Article, Professor Rubenstein expands the conversation outward by comparing class action law’s approach to relitigation of adequacy of representation with habeas corpus’s approach to relitigation of ineffective assistance of counsel claims in criminal cases. Using two recent, seemingly unconnected Supreme Court cases—one from each field—as case studies, Professor Rubenstein explains how these cases in fact raise remarkably similar questions. Specifically, the comparison reveals that habeas provides a relatively clear, rule-based system that specifies when—and according to what procedural rules—relitigation is available. Professor Rubenstein concludes by arguing that there are lessons for class action law in habeas’s approach: a method for considering when relitigation is appropriate that avoids the extremes of either “always” or “never”; a rule system that helps identify issues (such as substantive standards, degrees of deference, burdens of proof, and defaults) that have yet to be carefully examined in class action law; and a template for balancing the competing policy concerns at issue. Without defending current habeas doctrine, and without pretending that habeas and class actions are overtly similar, the Article nonetheless demonstrates that class action law’s relitigation problem can learn something through a close look at criminal law’s relitigation solutions.