For fifty years, courts have used a “reasonable expectation of privacy” standard to define “searches” under the Fourth Amendment. As others have recognized, that doctrine is subjective, unpredictable, and conceptually confused, but viable alternatives have been slow to emerge. This Article supplies one.

We argue that Fourth Amendment protection should be anchored in background positive law. The touchstone of the search-and-seizure analysis should be whether government officials have done something forbidden to private parties. It is those actions that should be subjected to Fourth Amendment reasonableness review and the presumptive requirement to obtain a warrant. In short, Fourth Amendment protection should depend on property law, privacy torts, consumer laws, eavesdropping and wiretapping legislation, anti-stalking statutes, and other provisions of law generally applicable to private actors, rather than a freestanding doctrine of privacy fashioned by courts on the fly.

This approach rests on multiple grounds. It is consistent with the history of the Fourth Amendment and with the structure of protection in the closely related area of constitutional property. It draws upon fundamental principles of liberal constitutionalism, namely a concern about abuse of official power. And it is superior to current privacy-based doctrine in many practical ways: it is clearer, more predictable, more accommodating of variation in different times and places, and more sensitive to the institutional strengths of legislative bodies, particularly when it comes to issues presented by new technologies.

It also has significant doctrinal implications. Of most immediate importance, it provides a framework to analyze third-party problems — situations in which information about one person is obtained from another — that is more coherent and more attractive than the modern third-party doctrine. It also provides a new framework for many other contested Fourth Amendment questions, from abandoned property and DNA to the use of drones.

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129 Harvard Law Review 1821-1889 (2016)