There is great confusion among scholars and courts about whether and when appellate courts may, or must, defer to trial courts' findings of social fact in constitutional rights cases. The Supreme Court has never directly decided the question and indeed has addressed it only once, in passing. A common assumption, promoted by scholars and adopted as binding by some circuits, is that the deferential, "clearly erroneous" standard of Federal Rule of Civil Procedure 52(a)(6) does not apply to social facts. This Article challenges that assumption. There is nothing in the text of the rule that supports this conclusion. Moreover, except in certain readily identifiable circumstances, it makes sense for appellate courts to defer to trial courts' findings of social fact. Federal bench trials are better suited than the appellate process to vetting social facts when laws are challenged as violating constitutional rights. When key social facts are missing from the trial record, a remand for further factfinding at the trial level will often be workable and appropriate. Since a court's findings of social fact can determine whether constitutional rights claims succeed or fail, it is crucial to achieve a clearer understanding of the roles and respective authority of appellate and trial courts in factfinding in constitutional rights cases. This Article sorts out the tangle of rules and precedents concerning appellate review of trial court factfinding in the constitutional rights context. It then proposes a framework for assessing whether and when appellate courts should defer to trial courts' findings of social fact in constitutional rights cases.