The Federalist Society’s journal Engage has an interesting Symposium on the National Security Agency’s Bulk Data Seizures and FISA Surveillance Programs. The symposium includes my very brief essay with Cato’s Jim Harper, Why NSA’s Bulk Data Seizures Are Illegal and Unconstitutional. In it we contend that:
Rather than airy and untethered speculations about “reasonable expectations,” the courts should return to the traditional—and more readily administrable—property and contract rights focus of Fourth Amendment protection reflected in the majority opinion in Katz. Courts should examine how parallels to the walls of the home and the phone booth in Katz conceal digital information are employed by the people to preserve their privacy.
In short, the physical and legal barriers people place around their information define both their actual and “reasonable” expectations of privacy and should provide the doctrinal touchstone of the search warrant requirement. When one has arranged one’s affairs using physics and the law of property and contract to conceal information from preying eyes, government agents may not use surreptitious means and outré technologies like thermal imaging to defeat those arrangements without obtaining a warrant that conforms to the requirement of the Fourth Amendment. In Jones, the Court took