The Fourth Amendment and General Law

For decades, Fourth Amendment protections have turned on “reasonable expectations of privacy.” But a new era may be dawning. There is growing interest among judges and scholars in turning away from privacy toward property or positive law as the touchstone for Fourth Amendment protections. Yet many questions remain about how that approach should work, such as where judges should look for positive law and precisely what role positive law should play in Fourth Amendment analysis.<br><br>This Article answers those questions, and in so doing lays forth a new, comprehensive theory of the Fourth Amendment. We argue that courts should interpret the Fourth Amendment’s protections by looking to “general law”—the common law under the control of no particular sovereign. Courts looking to general law would draw on ancient property concepts such as trespass, license, and bailments in determining the scope of protections. But they would also draw on custom, social practices, and modern legal developments to identify and flesh out common-law rules unknown at the Founding.<br><br>The general-law approach has numerous advantages over competitor theories. It makes better sense of the Fourth Amendment’s text and has deeper roots in its history. It is surprisingly easy to reconcile with a great deal of Fourth Amendment doctrine, while also suggesting important refinements in various areas. And it gives courts the flexibility to protect Fourth Amendment values in a changing world while also structuring and guiding the judicial task more than an untethered inquiry into privacy expectations. Private law, then, holds the key to understanding the Fourth Amendment’s limits on public power.