389 U.S. 347 (1967), argued 17 Oct. 1967, decided 18 Dec. 1967 by vote of 7 to 1; Stewart for the Court, Harlan and White concurring, black in dissent, Marshall not participating. Katz altered significantly the approach that courts must use in determining, under the Fourth Amendment, whether certain police conduct constitutes a “search” that is subject to the amendment's warrant and probable cause limitations. Illustrative of the pre‐Katz approach is Olmstead v. United States (1928), where the Supreme Court held that it did not constitute a search for the authorities to place a tap on certain telephone wires and thereby eavesdrop on the defendant's telephone conversations. As the Court later put the matter in Silverman v. United States (1961), for there to be a Fourth Amendment search the police must have physically intruded into “a constitutionally protected area” (p. 682). Katz replaced the Silverman standard with a reasonable expectation of privacy test.
At his trial for transmitting wagering information by phone, the government introduced over Katz's objection evidence of his end of telephone conversations, overheard by federal agents who had attached an electronic listening/recording device to the exterior of a public phone booth habitually used by Katz. The lower court concluded there was no search because the wall of the booth had not been physically penetrated. The Supreme Court reversed, holding that “[t]he Government's activities in electronically listening to and recording the petitioner's words violated the privacy upon which he justifiably relied while using the telephone booth and thus constituted a ‘search and seizure’ within the meaning of the Fourth Amendment” (p. 512). This proposition was elaborated in Justice John M. Harlan's concurring opinion, later relied upon by lower courts and the Supreme Court itself in determining the meaning of Katz. Harlan stated that “there is a twofold requirement, first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as ‘reasonable’” (p. 516).
The first branch of the Harlan formulation should not be a part of any statement of what the Fourth Amendment protects. This is because the government could easily, either by edict or systematic practice, condition the expectations of the general public in such a way that there would be no hope of privacy. Harlan later appreciated this, stating in United States v. White (1971) that analysis under Katz must “transcend the search for subjective expectations” (p. 786). The Supreme Court has seldom addressed this point in more recent cases, though some of its statements are legitimate cause for concern. Illustrative is California v. Ciraolo (1986), holding that it is not a search to make an aerial observation of marijuana plants growing inside a fenced backyard, where it was intimated that defendant's ten‐foot high solid wood fence would not provide a subjective expectation of privacy because the plants could be seen by “a policeman perched on the top of a truck or a two‐level bus” (p. 211). A person is unlikely therefore to get by the first Katz hurdle unless he or she has taken steps to ensure against all conceivable efforts at scrutiny.
As for the second prong of the Harlan elaboration, he stressed in White that “those more extensive intrusions that significantly jeopardize the sense of security which is the paramount concern of Fourth Amendment liberties” are searches (p. 1143). Unfortunately, the Supreme Court has not interpreted Katz this way, as is evident from two cases: United States v. Miller (1976), holding that a person has no justified expectation of privacy in a bank's records of his financial transactions because those documents “contain only information voluntarily conveyed to the banks and exposed to their employees in the ordinary course of business” (p. 442); and Ciraolo, holding that it is not a search for police to look down from an airplane into one's solidly fenced yard because “any member of the public flying over this airspace who glanced down could have seen everything that these officers observed” (pp. 213–214). In these and other cases the Court has failed to appreciate, as Justice Thurgood Marshall put it in his Smith v. Maryland (1979) dissent, that “privacy is not a discrete commodity, possessed absolutely or not at all” (p. 749).
Bibliography
- Wayne R. LaFave, The Forgotten Motto of Obsta Principiis in Fourth Amendment Jurisprudence,
Arizona Law Review 28 (1986): 291–310
— Wayne R. La Fave
