Property Is Privacy: Locke and Brandeis in the Twenty-First Century

For fifty years Katz v. United States has played a central role in defining both how the Fourth Amendment regulates electronic surveillance by the government and the nature of the links between the Fourth Amendment and property rights—links established by the Amendment’s eighteenth century text. In Katz, the Supreme Court attempted to create a theory for resolving both issues by disavowing the traditional property-based foundations of Fourth Amendment rights and replacing them with an analytical process that has come to be known as the reasonable expectation of privacy test. The central theme of this article is that the decision to abandon the property basis for rights adopted in the Fourth Amendment was unnecessary. In Katz the Supreme Court overruled a narrow concept of property rights first announced in Olmstead v. United States in 1928. The theories introduced in Olmstead were, in fact, inconsistent with the Fourth Amendment’s legal, political, and philosophical origins, as well as more than forty years of Supreme Court decisions using a broad theory of property rights to interpret the Fourth Amendment. Before Olmstead, Fourth Amendment rights were tied closely to a broad definition of property articulated by John Locke in the seventeenth century. A broad Lockean theory of property was embedded in the Fourth Amendment’s eighteenth century text and history, and was a fundamental element of the Supreme Court’s interpretation of the Amendment for over forty years in the nineteenth and twentieth centuries. In this paper I explore this “broad” theory of property and propose that it could provide robust tools for protecting privacy and liberty from technological intrusions, particularly intrusions upon digital information. The broad theory of property can apply to digital information, for example, because it protects more than tangible things. As understood during the century leading up to the Founding, the broad concept of property included a person’s rights, ideas, beliefs, and the creative products of her labor. It provided robust protection for the contents of expressive property including, but not limited to, private papers. And courts applying broad theories of property regularly employed flexible interpretive methods that protected liberty, even if this obstructed the efficient exercise of government power. When the paper turns from Locke to Brandeis, we find that Louis Brandeis’ seminal theories about the legal right to privacy shared core values with broad Lockean property theories. The values underlying privacy and property theories produced similar results in actual disputes, particularly when government used technology to conduct searches and seizures. Finally, the paper explains how recent Supreme Court opinions regulating both physical property and expressive digital information are consistent with broad property theories. In fact, in each case property theory may provide a better explanation for the Supreme Court's decisions than does the Katz expectation of privacy test. l do not propose that we should—or could—adopt seventeenth, eighteenth, and nineteenth century doctrines to resolve all twenty-first century disputes. Time does work changes. More than three centuries have passed since Locke published his Second Treatise of Government, and more than two centuries have passed since the Revolutionary and Founding generations embraced many of his ideas. What I hope to demonstrate in this article is that although the vocabularies and intellectual constructs of liberty have changed with the passage of time, the foundational values undergirding the Fourth Amendment have not. We face different practical problems today, but concepts of liberty embedded in the phrase “persons, houses, papers, and effects” persist.