The Bilateral Fourth Amendment and the Duties of Law-Abiding Persons

Abstract

The Fourth Amendment protects the innocent only from “unreasonable” searches. In lieu of the limited nature of this constitutional safeguard, law abiders consistently take precautions to avoid government searches. This Article considers why constitutional jurisprudence limits the protection of the innocent to “unreasonable” searches, thereby forcing them to alter their behavior. The most satisfying answer derives from an often overlooked fact: Searches of innocent persons are often “bilateral accidents,” meaning that both the innocent suspect and the police can affect the likelihood of an erroneous search occurring. In bilateral conditions, a reasonableness rule induces both the searcher and searched to take optimal care to avoid mistaken searches, while other rules embodied in constitutional protections — like that within the Takings Clause — cannot.

By assigning costs for erroneous-but-reasonable searches to the innocent, the Fourth Amendment functions as an important regulatory device, channeling law abiders away from activity that unintentionally masks others’ criminal enterprises. Thus, the Amendment regulates the very people that it protects from governmental intrusions. This Article refers to this duality as the “bilateral Fourth Amendment,” and argues the Amendment’s incentives for the innocent are best understood as a duty for law-abiding people to act reasonably.

At the same time, identifying the “bilateral” nature of searches should influence the legal rules dictating what evidence police may use as grounds to search a suspect. Because the innocent alter their behavior based on which activities the government deems “suspicious,” rules about cause and suspicion cannot singly turn on evidence’s probative value; they must also account for the socially beneficial activity that is reduced by labeling behavior “suspicious.”

Keywords: Fourth Amendment, Law and Economics, Constitutional Law