American proponents of legal formalism, such as Supreme Court Justice Antonin Scalia, worry (quite reasonably) that unfettered judicial discretion poses a threat to democratic legitimacy, and they offer formalism—the mechanical implementation of determinate legal rules—as a solution to this threat. I argue here, however, that formalist interpretive techniques are neither sufficient nor necessary ... [Show full abstract] to impose meaningful constraint on judges. Both the text and the “original meaning” of legal rules are endemically under-determinate, leaving much room for judicial discretion in the decision of cases. But meaningful judicial constraint can and does flow from other sources in American adjudication. Judges are constrained by the dispute-resolving posture of their task, which requires that they be impartial as between the litigants and responsive to the litigants’ participatory efforts. And they are constrained by the need to be faithful to the substantive principles that justify legal rules, even when those rules themselves are indeterminate. Judicial constraint in the American system thus stems not primarily from formalist interpretative methods, but rather from largely unwritten procedural principles of judicial impartiality, responsiveness, and faithfulness.