Dark Matter in the Law

Not all law is written down. Sometimes, informal norms and expectations about what the law is or ought to be constrain behavior. Lawyers and legal commentators instinctively understand this concept and have written about it, but none have discussed the interaction or relationship between these unwritten norms—which I refer to as law’s “dark matter”—and traditional formal law, like case law and statutes—which I refer to as law’s “ordinary matter.” I venture into this overlooked relationship to reveal a fascinating and important dynamic that shapes the development of law. In this Article, I explore law’s dark matter by observing its effect on law’s ordinary matter. I focus on the interaction between dark matter and court precedent, and I show how dark matter can play a significant, and even primary, role in shaping behavior despite the existence of contrary precedent in the field. I illustrate this curious phenomenon primarily with reference to The Chinese Exclusion Case, an 1889 Supreme Court decision that remains formally “on the books” but seems inimical to modern conceptions of constitutional law. I also briefly examine Korematsu v. United States, Buck v. Bell, and their interaction with subsequently developed dark matter. From my examination of these cases and their subsequent treatment by legal actors, I argue that, counterintuitively, dark matter can weaken ordinary matter—formal law—while at the same time insulating that ordinary matter from review and possible rescission. I identify three factors that can lead to the development of dark matter with this effect. I also posit that dark matter has more influence on legislative bodies and courts than on the executive branch, and I examine the implications of this discrepancy in dark matter’s power.