The Qualitative Dimension of Fourth Amendment Reasonableness

Supreme Court doctrine protects two seemingly distinct kinds of interests under the heading of privacy rights: one substantive, the other procedural. The Fourth Amendment guarantee against unreasonable searches and seizures has been generally interpreted to protect procedural privacy. Searches are typically defined as governmental inspections of activities and locations in which an individual has a reasonable expectation of privacy from observation. In the typical case, this reasonable expectation of privacy may be breached only where the government has acquired a quantitatively substantial objective basis for believing that the search would uncover evidence of a crime. Substantive privacy rights have not normally been considered in this inquiry. This Article argues that a focus on the quantitative basis for finding probable cause is incomplete. As a corrective, Professor Colb urges a vision of the Fourth Amendment reasonableness requirement that contains both substantive and procedural safeguards. This critique of the quantitative approach to Fourth Amendment jurisprudence suggests that the Court ought to engage in substantively balancing the interests served by particular classes of searches and seizures against the costs of such government activity for the individual\u27s sense of security and privacy, even in cases in which the government must also have probable cause and a warrant before proceeding. Such an integration of substantive and procedural privacy, one that engaged in a Fourth Amendment inquiry regarding the intrusiveness of a search or seizure, would more effectively further the privacy values embraced by the Court\u27s criminal procedure and substantive constitutional precedents