warrants." Revisions accomplished under circumstances that are still unclear transformed the Amendment into two separate clauses. The change has influenced our understanding of the nature of the rights it protects. As embodied in our Constitution, the Amendment reads: "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, suported by oath or affirmation, and particular describing the place to be searched, and the persons or things to be seized."

Our understanding of the purposes underlying the Fourth Amendment has been an evolving one. It has been shaped by subsequent historical events, by the changing conditions of our modern technological society, and by the development of our own traditions, customs, and values. From the beginning, of course, there has been agreement that the Amendment protects against practices such as those of the Crown officers under the notorious general warrants and writs of assistance. Above all, the Amendment safeguards the people from unlimited, undue infringement by the government on the security of persons and their property.

But our perceptions of the language and spirit of the Amendment have gone beyond the historical wrongs the Amendment was intended to prevent. The Suprme Court has served as the primary explicator of these evolving perceptions and has sought to articulate the values the Amendment incorporates. I believe it is useful in our present endeavor to identify some of these perceived values. First, broadly considered, the Amendment speaks to the autonomy of the individual against society. It seeks to accord to each individual, albeit imperfectly, a measure of the confidentiality essential to the attainment of human dignity. It is a shield against indiscriminate exposure of an individual's private affairs to the world-an exposure which can destroy, since it places in jeopardy the spontaneity of thought and action on which so much depends. As Justice Brandeis observed in his dissent in the Olmstead case, in the Fourth Amendment the Founders "conferred, as against the Government, the right to be let alonethe most comprehensive of rights and the right most valued by civilized men." 12 Judge Jerome Frank made the same point in a dissent in a case in which a paid informer with a concealed microphone broadcast an intercepted conversation to a narcotics agent. Judge Frank wrote that "[a] sane, decent, civilized society must provide some such oasis, some shelter from public scrutiny, some insulated enclosure, some enclave, some inviolate place which is a man's castle." 18 The Amendment does not protect absolutely the privacy of an individual. The need for privacy, and the law's response to that need, go beyond the Amendment. But the recognition of the value of individual autonomy remains close to the Amendment's core.

A parallel value has been the Amendment's special concern with intrusions when the purpose is to obtain evidence to incriminate the victim of the search. As the Supreme Court observed in Boyd, which involved an attempt to compel the production of an individual's private papers, at some point the Fourth Amendment's prohibition against unreasonable searches and seizures and the Fifth Amendment's prohibition against compulsory self-incrimination "run almost into each other." 14 The intrusion on an individual's privacy has long been thought to be especially grave when the search is based on a desire to discover incriminating evidence. 15

11 Madison's proposal read as follows:

"The rights of the people to be secured in their persons, their homes, their papers. and their own property, from all unreasonable searches and seizures, shall not be violated by warrants issued without probable cause, supported by oath or affirmation, or not particularly describing the places to be searched, or the persons or things to be seized."

Annals of Cong., 1st Cong., 1st Sess.. p. 452.

The desire to incriminate may be seen as only an aggravating circumstance of the search, but it has at times proven to be a decisive factor in determining its legality. Indeed, in Boyd the Court declared broadly that "compelling the production of [a person's] private books and papers, to convict him of crime, or to forfeit his property, is contrary to the principles of a free government." 16 The incriminating evidence point goes to the integrity of the criminal justice system. It does not necessarily settle the issue whether the overhearing can properly take place. It goes to the use and purpose of the information overheard.

An additional concern of the Amendment has been the protection of freedom of thought, speech, and religion. The general warrants were used in England as a powerful instrument to suppress what was regarded as seditious libel or nonconformity. Wilkes was imprisoned in the Tower and all his private papers seized under such a warrant for his criticism of the King. As Justice Frankfurter inquired, dissenting in a case that concerned the permissible scope of searches incident to arrest, "How can there be freedom of thought or freedom of speech or freedom of religion, if the police can without warrant, search your house and mine from garret to cellar. .?" 17 So Justice Powell stated in Keith that "Fourth Amendment protections become the more necessary when the targets of official surveillance may be those suspected of unorthodoxy in their political beliefs." 18

Another concern embodied in the Amendment may be found in its second clause dealing with the warrant requirement, even though the Fourth Amendment does not always require a warrant. The fear is that the law enforcement officer, if unchecked, may misuse his powers to harass those who hold unpopular or simply different views and to intrude capriciously upon the privacy of individuals. It is the recognition of the possibility for abuse, inherent whenever executive discretion is uncontrolled, that gives rise to the requirement of a warrant. That requirement constitutes an assurance that the judgment of a neutral and detached magistrate will come to bear before the intrusion is made and that the decision whether the privacy of the individual must yield to a greater need of society will not be left to the executive alone.

A final value reflected in the Fourth Amendment is revealed in its opening words: "The right of the people." Who are "the people" to whom the Amendment refers? The Constitution begins with the phrase, "We the People of the United States." That phrase has the character of words of art, denoting the power from which the Constitution comes. It does suggest a special concern for the American citizen and for those who share the responsibilities of citizens. The Fourth Amendment guards the right of "the people" and it can be urged that it was not meant to apply to foreign nations, their agents and collaborators. Its application may at least take account of that difference.

The values outlined above have been embodied in the Amendment from the beginning. But the importance accorded a particular value has varied during the course of our history. Some have been thought more important or more threatened than others at times. When several of the values coalesce, the need for protection has been regarded as greatest. When only one is involved, that need has been regarded as lessened. Moreover, the scope of the Amendment itself has been altered over time, expanding or contracting in the face of changing circumstances and needs. As with the evolution of other constitutional provisions, this development has been case in definitional terms. Words have been read by different Justices and different Courts to mean different things. The words of the Amendment have not changed; we, as a people, and the world which envelops us, have changed.

An important example is what the Amendment seeks to guard as "secure." The wording of the Fourth Amendment suggests a concern with tangible property. By its terms, the Amendment protects the right of the people to be secure in their "persons, houses, papers and effects." The emphasis appears to be on the material possessions of a person, rather than on his privacy generally. The Court came to that conclusion in 1928 in the Olmstead case, holding that the interception of telephone messages, if accomplished without a physical trespass, was outside the scope of the Fourth Amendment. Chief Justice Taft, writing for the Court, reasoned that wiretapping did not involve a search or seizure; the Amendment protected only tangible material "effects" and not intangibles such as oral conversations. A thread of the same idea can be found in Entick, where Lord Camden said: "The great end for which men entered into society was to

secure their property." But, while the removal and carrying off of papers was a trespass of the most aggravated sort, inspection alone was not: "the eye," Lord Camden said, "cannot by the law of England be guilty of a trespass."

21

The movement of the law since Olmstead has been steadily from portection of property to protection of privacy. In the Goldman case 20 in 1942 the Court held that the use of a detectaphone placed against the wall of a room to overhear oral conversations in an adjoining office was not unlawful because no physical trespass was involved. The opinion's unstated assumption, however, appeared to be that a private oral conversation could be among the protected "effects" within the meaning of the Fourth Amendment. The Silverman case later eroded Olmstead substantially by holding that the Amendment was violated by the interception of an oral conversation through the use of a spike mike driven into a party wall, penetrating the heating duct of the adjacent home. The Court stated that the question whether a trespass had occurred as a technical matter of property law was not controlling; the existence of an actual intrusion was sufficient.

The Court finally reached the opposite emphasis from its previous stress on property in 1967 in Katz v. United States. The Court declared that the Fourth Amendment "protects people, not places," against unreasonable searches and seizures; that oral conversations, although intangible, were entitled to be secure against the uninvited ear of a government officer, and that the interception of a telephone conversation, even if accomplished without a trespass, violated the privacy on which petitioner justifiably relied while using a telephone booth. Justice Harlan, in a concurring opinion, explained that to have a constitutionally protected right of privacy under Katz it was necessary that a person, first, "have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognized as 'reasonable.' " 23 At first glance, Katz might be taken as a statement that the Fourth Amendment now protects all reasonable expectations of privacy-that the boundaries of the right to privacy are coterminous with those of the Fourth Amendment. But that assumption would be misleading. To begin with, the Amendment still protects some interests that have very little if anything to do with privacy. Thus, the police may not, without warrant, seize an automobile parked on the owners' driveway even though they have reason to believe that the automobile was used in committing a crime. The interest protected by the Fourth Amendment in such a case is probably better defined in terms of property than privacy. Moreover, the Katz opinion itself cautioned that "the Fourth Amendment cannot be translated into a general constitutional 'right to privacy."2" Some privacy interests are protected by remaining Constitutional guarantees. Others are protected by federal statute, by the states, or not at all.

The point is twofold. First, under the Court's decisions, the Fourth Amendment does not protect every expectation of privacy, no matter how reasonable or actual that expectation may be. It does not protect, for example, against false friends' betrayals to the police of even the most private confidences. Second, the "reasonable expectation of privacy" standard, often said to be the test of Katz, is itself a conclusion. It represents a judgment that certain behavior should as a matter of law be protected against unrestrained governmental intrusion. That judgment, to be sure, rests in part on an assessment of the reasonableness of the expectation, that is, on an objective, factual estimation of a risk of intrusion under given circumstances, joined with an actual expectation of privacy by the person involved in a particular case. But it is plainly more than that, since it is also intermingled with a judgment as to how important it is to society that an expectation should be confirmed-a judgment based on a perception of our customs, traditions, and values as a free people.

The Katz decision itself illustrates the point. Was it really a "reasonable expectation" at the time of Katz for a person to believe that his telephone conversation in a public phone booth was private and not susceptible to interception by a mircrophone on the booth's outer wall? Almost forty years earlier in Olmstead the Court held that such nontrespassory interceptions were permissible. Goldman reaffirmed that holding. So how could Katz reasonably expect the contrary? The answer, I think, is that the court's decision in Katz turned ultimately on an assessment of the effect of permitting such unrestrained intrusions on the individual in his private and social life. The judgment was that a license for unlimited

governmental intrusions upon every telephone would pose too great a danger to the spontaneity of human thought and behavior. Justice Harlan put the point this way:

"The analysis must, in my view, transcend the search for subjective expectations or legal attribution of assumptions of risk. Our expectations, and the risks we assume, are in large part reflections of laws that translate into rules the customs and values of the past and present." ته

A weighing of values is an inescapable part in the interpretation and growth of the Fourth Amendment. Expectations, and their reasonableness, vary according to circumstances. So will the need for an intrusion and its likely effect. These elements will define the boundaries of the interests which the Amendment holds as "secure."

To identify the interests which are to be "secure," of course, only begins the inquiry. It is equally essential to identify the dangers from which those interests are to be secure. What constitutes an intrusion will depend on the scope of the protected interest. The early view that the Fourth Amendment protected only tangible property resulted in the rule that a physical trespass or taking was the measure of an intrusion. Olmstead rested on the fact that there had been no physical trespass into the defendant's home or office. It also held that the use of the sense of hearing to intercept a conversation did not constitute a search or seizure. Katz, by expanding the scope of the protected interests, necessarily altered our understanding of what constitutes an intrusion. Since intangibles such as oral conversations are now regarded as protected "effects," the overhearing of a conversation may constitute an intrusion apart from whether a physical trespass is involved.

The nature of the search and seizure can be very important. An entry into a house to search its interior may be view as more serious than the overhearing of a certain type of conversation. The risk of abuse may loom larger in one case than the other. The factors that have come to be viewed as most important, however, are the purpose and effect of the intrusion. The Supreme Court has tended to focus not so much on what was physically done, but on why it was done and what the consequence is likely to be. What is seized, why it was seized, and what is done with what is seized are critical questions.

I stated earlier that a central concern of the Fourth Amendment was with instrusions to obtain evidence to incriminate the victim of the search. This concern has been reflected in Supreme Court decisions which have traditionally treated intrusions to gather incriminatory evidence differently from intrusions for neutral or benign purposes. In Frank v. Maryland, the appellant was fined for refusing to allow a housing inspector to enter his residence to determine whether it was maintained in compliance with the municipal housing code. Violation of the code would have led only to a direction to remove the violation. Only failure to comply with the direction would lead to a criminal sanction. The Court held that such administrative searches could be conducted without warrant.

Justice Frankfurter, writing for the Court, noted that the Fourth Amendment was a reaction to "ransacking by Crown officers of the homes of citizens in search of evidence of crime or of illegally imported goods." He observed that both Entick and Boyd were concerned with attempts to compel individuals to incriminate themselves in criminal cases and that "it was on the issue of the right to be secure from searches for evidence to be used in criminal prosecutions or for forfeitures that the great battle for fundamental liberty was fought." 28 There was thus a great difference, the Justice said, between searches to seize evidence for criminal prosecutions and searches to detect the existence of municipal health code violations. Searches in this later category, conducted "as an adjunct to a regulatory scheme for the general welfare of the community and not as a means of enforcing the criminal law, [have] antecedents deep in our history," and should not be subjected to the warrant requirement.

21

Frank was later overruled in 1967 in Camara v. Municipal Court, and a companion case, See v. City of Seattle. In Camara, appellant was, like Frank. charged with a criminal violation as a result of his refusal to permit a municipal inspector to enter his apartment to investigate possible violations of the city's housing code. The Supreme Court rejected the Frank rationale that municipal fire, health, and housing inspections could be conducted without a warrant because the object of the intrusion was not to search for the fruits or instrumentalities of crime. Moreover, the Court noted that most regulatory laws such as fire, health, and housing codes were enforced by criminal processes, that refusal to permit entry to an inspector was often a criminal offense, and that the "self-protection" or "non-incrimination" objective of the Fourth Amendment was therefore indeed involved.

But the doctrine of Camara proved to be limited. In 1971 in Wyman v. James the Court held that a "home visit" by a welfare caseworker, which entailed termination of benefits if the welfare recipient refused entry, was lawful despite the absence of a warrant. The Court relied on the importance of the public's interest in obtaining information about the recipient, the reasonableness of the measures taken to ensure that the intrusion was limited to the extent praсticable, and most importantly, the fact that the primary objective of the search was not to obtain evidence for a criminal investigation or prosecution. Camara and Frank were distinguished as involving criminal proceedings.

Perhaps what these cases mainly say is that the purpose of the intrusion, and the use to which what is seized is put, are more important from a constitutional standpoint than the physical act of intrusion itself. Where the purpose or effect is noncriminal, the search and seizure is perceived as less troublesome and there is a readiness to find reasonableness even in the absence of a judicial warrant. By contrast, where the purpose of the intrusion is to gather incriminatory evidence, and hence hostile, or when the consequence of the intrusion is the sanction of the criminal law, greater protections may be given.

The Fourth Amendment then, as it has always been interpreted, does not give absolute protection against Government intrusion. In the words of the Amendment, the right guaranteed is security against unreasonable searches and seizures. As Justice White said in the Camara case, "there can be no ready test for determining reasonableness other than by balancing the need to search against the invasion which the search entails." 33 Whether there has been a constitutionally prohibited invasion at all has come to depend less on an absolute dividing line between protected and unprotected areas, and more on an estimation of the individual security interests affected by the Government's actions. Those effects, in turn, may depend on the purpose for which the search is made, whether it is hostile, neutral, or benign in relation to the person whose interests are invaded, and also on the manner of the search.

By the same token, the Government's need to search, to invade individual privacy interests, is no longer measured exclusively if indeed it ever was-by the traditional probable cause standard. The second clause of the Amendment states, in part, that "no warrants shall issue but upon probable cause." The concept of probable cause has often been read to bear upon and in many cases to control the question of the reasonableness of searches, whether with or without warrant. The traditional formulation of the standard, as "reasonable grounds for believing that the law was being violated on the premises to be searched" relates to the Governmental interest in the prevention of criminal offenses, and to seizure of their instruments and fruits. This formulation once took content from the long-standing "mere evidence rule"-that searches could not be undertaken "solely for the purpose of [securing] evidence to be used in a criminal or penal proceeding, but that they may be resorted to only when a primary right to such search and seizure may be found in the interest which the public... may have in the property to be seized." The Government's interest in the intrusion, like the individual's interest in privacy, thus was defined in terms of property, and the right to search as well as to seize was limited to items-contraband and the fruits and instrumentalities of crime-in which the Government's interest was thought superior to the individual's. This notion, long eroded in practice, was expressly abandoned by the Court in 1967 in Warden v. Hayden. Thus, the detection of crime the need to discover and use "mere evidence"-may presently justify intrusion.

Moreover, as I have indicated, the Court has held that, in certain situations, something less than probable cause-in the traditional sense-may be sufficient ground for intrusion, if the degree of intrusion is limited strictly to the purposes

32 400 U.S. 309.

33 387 U.S. 523.536-37 (1967).

Brinegar v. United States, 338 U.S. 160, 1975 (1949).
Gouled v. United States, 255 U.S. 298, 309 (1921).