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 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...