Katz is dead. Long live Katz.

• Author: Swire, Peter P.
• Position: Applying the Fourth Amendment to electronic surveillance

Katz v. United States is the king of Supreme Court surveillance cases. (1) Written in 1967, it struck down the earlier regime of property rules, declaring that "the Fourth Amendment protects people, not places." (2) The concurrence by Justice Harlan announced the new regime--court-issued warrants are required where there is an infringement on a person's "reasonable expectation of privacy." (3) Together with the companion case Berger v. New York, (4) Katz has stood for a grand conception of the Fourth Amendment as a bulwark against wiretaps and other emerging forms of surveillance.

Professor Orin Kerr, in his excellent article, shows that this view of Katz fits badly with how courts now apply the Fourth Amendment to electronic surveillance and other new technology. (5) Upon reading his own obituary, Mark Twain famously observed that "reports of my death are greatly exaggerated." (6) This Essay shows that the demise of Katz has actually been understated. Professor Kerr has correctly shown how the property regime has persisted where it helped the government, such as cases that hold that many kinds of surveillance are not "searches" under the Fourth Amendment. This Essay adds the insight that the property regime has actually been abandoned in many other respects since 1967, in ways that have dramatically aided government surveillance. In particular, as discussed in Part I, the 1967 abolition of the "mere evidence" rule has given the government unprecedented access to diaries, private papers, and other information of individuals.

Examination of the case law and of new developments in telephone technology leads to a second insight. The shift to Voice over Internet Protocol phone calls means that the content of many telephone calls will likely be subject to routine recording in the near future. Because the Supreme Court has been so supportive of government access to stored records, Katz and Berger may soon be dead for their core facts, the content of phone calls.

If Katz is dead (or nearly so), what should be done? Professor Kerr appears to welcome the demise of Katz. He argues at length that Congress can do a better job than the courts at creating the law for high-tech surveillance. This Essay criticizes that view, showing reasons why Fourth Amendment doctrine should continue to play a role in governing electronic surveillance and other high-tech searches. At a minimum, the Court should announce basic principles for how surveillance can be conducted, with Congress then supplying the details.

The end of Katz, perhaps even on its own facts, invites us to consider what alternative approaches the courts might take in structuring a regime for high-tech surveillance by the government. This Essay sketches some of the substantive doctrines that courts might workably enforce in defining Fourth Amendment searches. It then explores in some detail the possibility that the courts can work collaboratively with the elected branches to ensure that there are reasonable procedures in place. The new regime would uphold the rule of law, with reasonable procedures specified in advance. This approach would give both the courts and the elected branches appropriate roles in important categories of searches, such as those involving emerging technologies, new types of surveillance, and complex record-keeping systems.

1. THE END OF THE PROPERTY REGIME AS SWORD, NOT SHIELD

   A key achievement of Professor Kerr's article is to describe how the property approach to the Fourth Amendment has survived Katz: "[I]n most (though not all) cases, an expectation of privacy becomes 'reasonable' only when it is backed by a right to exclude borrowed from real property law." (7) He adds: "Although no one theory explains the entire body of Fourth Amendment doctrine, property law provides a surprisingly accurate guide." (8) Despite the many citations to Katz's "reasonable expectation of privacy" test in the courts and in law reviews, there has been no case beyond wiretapping where application of the test has led to protection of privacy. (9) Put mildly, Katz has not been a good shield for privacy against intrusive new technologies. (10)

   Professor Kerr's article thus helps us to see clearly what is happening--despite the comforting discussion of privacy expectations, the courts continue to apply a property-based approach to new technologies. This description, however, tells only half the story. The Supreme Court did in fact abandon the property-based approach in 1967 in ways that have continuing major effects, but it actually did so in the direction of reducing the privacy protection offered by prior law. In the same year as Katz, in Warden v. Hayden, (11) the Supreme Court abolished the "mere evidence" rule. That rule had previously set limits on the ability of a search warrant to authorize collection of documents and other "mere evidence" of a crime. By examining the shifts in the "mere evidence" rule, we can re-envision the 1967 abandonment of the property-based approach as a sword for greater entry into private spaces, and not the shield for protecting privacy that most have supposed.

   The "mere evidence" rule was a matter of common sense under the property-based approach to the Fourth Amendment. A search warrant could lawfully issue for items where the property interest of the government was superior to that of the person holding the object. Notably, an individual could claim no legitimate property interest in the fruits of a crime, such as: stolen goods; its instrumentalities, such as the knife used in the crime; or in contraband, such as illegal narcotics. By contrast, a person's private papers were long understood to be outside the reach of a search warrant under the authority of the 1765 case of Entick v. Carrington, (12) as interpreted by the Supreme Court in Boyd v. United States (13) and Gouled v. United States. (14)

   Justice Brennan authored the opinion in Hayden that overturned the "mere evidence" rule. He stated: "The premise that property interests control the right of the Government to search and seize has been discredited." (15) Emphasizing that "the principal object of the Fourth Amendment is the protection of privacy rather than property," (16) he foreshadowed by less than a year the statement in Katz that "the Fourth Amendment protects people, not places." Justice Brennan seems to have contemplated a symmetry in the change of doctrine. The "reasonable expectation of privacy" approach created a doctrine that would apply both in settings where government powers would expand (allowing seizure of the clothes found in Hayden) and would recede (prohibiting the wiretap in Katz). It is likely that Justice Brennan, writing for the liberal Warren Court, expected that the shift from the property approach to the privacy approach would result in an overall expansion of Fourth Amendment protections.

   The opposite has occurred. On a doctrinal level, the Court has been far stingier in finding a "reasonable expectation of privacy" than Justice Brennan foresaw. The Court has swept aside limits on government access to documents that would have existed under the old property approach. The result of the new doctrine has been to open the door to a far greater number of document searches than was previously permitted. Aficionados of the Fourth Amendment are familiar with the key cases. The focus here will be on how the announced shift from the property to the privacy approach has affected government access to records held by third parties.

   The narrow scope of the "reasonable expectation of privacy" test was established in United States v. Miller, which involved subpoenas for copies of checks written by the defendant. (17) The court of appeals struck down the subpoenas under the Fourth Amendment, citing the prohibition in Boyd v. United States against "'compulsory production of a man's private papers to establish a criminal charge against him.'" (18) The Supreme Court reversed. Justice Powell for the majority found that the defendant had no reasonable expectation of privacy. Justice Powell quoted Katz itself in saying "'[w]hat a person knowingly exposes to the public ... is not a subject of Fourth Amendment protection.'" (19) The crucial doctrinal finding was that the "checks are not confidential communications but negotiable instruments to be used in commercial transactions." (20) The subpoenas produced "only information voluntarily conveyed to the banks." Justice Brennan angrily dissented, (21) but Miller today stands for a broad proposition that individuals "voluntarily" reveal information when they give documents or data to third parties. Based on this individual "consent" to share data, the holders of data such as banks may pass on the data to the government without triggering Fourth Amendment requirements. (22)

   The limits of the "reasonable expectation of privacy" test, and the government's broad access to stored records, were reaffirmed in Smith v. Maryland. (23) The case presented the question whether the installation and use of a pen register constitutes a "search" under the Fourth Amendment. "Pen registers" create a list of all of the numbers dialed from a telephone, just as "trap and trace" devices create a list of the numbers that call into a telephone. (24) The Court held that there was no "reasonable expectation of privacy" in the list of phone numbers dialed, because "petitioner voluntarily conveyed to [the phone company] information that it had facilities for recording and that it was free to record." (25) This emphasis on the government's access to stored records has become increasingly important over time, as discussed further below. (26)

   Although the Court found that the bank or the phone company owned the records in these cases, it made clear that defendants' ownership of records would not protect those records from the government. In Couch v. United States, the question was whether a taxpayer could invoke the Fifth Amendment...