Courts often look to existing social norms to resolve difficult questions in Fourth Amendment law. In theory, these norms can provide an objective basis for courts’ constitutional decisions, grounding Fourth Amendment law in familiar societal attitudes and beliefs. In reality, however, social norms can shift rapidly, are constantly being contested, and frequently reflect outmoded and discriminatory concepts. This Article draws on contemporary sociological literatures on norms and technology to reveal how courts’ reliance on norms leads to several identifiable errors in Fourth Amendment jurisprudence.

Courts assessing social norms generally adopt what we call the closure principle, or the idea that social norms can be permanently settled. Meanwhile, courts confronting new technologies often adopt the nonintervention principle, or the idea that courts should refrain from addressing the Fourth Amendment implications of new surveillance practices until the relevant social norms become clear. Both approaches are flawed, and they have substantial negative effects for equality and privacy. By adopting norms perceived as closed, courts may embed antiquated norms in Fourth Amendment law—norms that often involve discrimination on the basis of race, gender, or class. By declining to intervene when norms are undeveloped, courts cede power over norm creation to companies that design new technologies based on data-extractive business models. Further, judicial norm reliance and nonintervention facilitate surveillance creep, the extension of familiar data-gathering infrastructures to new types of surveillance.

This Article provides, for the first time, a full, critical account of the role of social norms in Fourth Amendment law. It details and challenges courts’ reliance on social norms in virtually every aspect of Fourth Amendment jurisprudence. And it explores potential new directions for Fourth Amendment law, including novel doctrinal paradigms, different conceptions of stare decisis in the Fourth Amendment context, and alternative institutional regimes for regulating government surveillance.