Court Opinion

ID: 9429768
Source: CourtListenerOpinion
Date Created: 2023-08-02 23:27:49.620895+00
Date Added: 2024-06-11T17:23:21.466240
License: Public Domain

Justice Brennan,
with whom Justice Marshall joins, dissenting.*
Ten years ago in United States v. Calandra, 414 U. S. 338 (1974), I expressed the fear that the Court’s decision “may signal that a majority of my colleagues have positioned themselves to reopen the door [to evidence secured by official lawlessness] still further and abandon altogether the exclusionary rule in search-and-seizure cases.” Id., at 365 (dissenting opinion). Since then, in case after case, I have witnessed the Court’s gradual but determined strangulation *929of the rule.1 It now appears that the Court’s victory over the Fourth Amendment is complete. That today’s decisions represent the piece de resistance of the Court’s past efforts cannot be doubted, for today the Court sanctions the use in the prosecution’s case in chief of illegally obtained evidence against the individual whose rights have been violated — a result that had previously been thought to be foreclosed.
The Court seeks to justify this result on the ground that the “costs” of adhering to the exclusionary rule in cases like those before us exceed the “benefits.” But the language of deterrence and of cost/benefit analysis, if used indiscriminately, can have a narcotic effect. It creates an illusion of technical precision and ineluctability. It suggests that not only constitutional principle but also empirical data support the majority’s result. When the Court’s analysis is examined carefully, however, it is clear that we have not been treated to an honest assessment of the merits of the exclusionary rule, but have instead been drawn into a curious world where the “costs” of excluding illegally obtained evidence loom to exaggerated heights and where the “benefits” of such exclusion are made to disappear with a mere wave of the hand.
The majority ignores the fundamental constitutional importance of what is at stake here. While the machinery of law enforcement and indeed the nature of crime itself have changed dramatically since the Fourth Amendment became part of the Nation’s fundamental law in 1791, what the Framers understood then remains true today — that the task of combating crime and convicting the guilty will in every era seem of such critical and pressing concern that we may be lured by the temptations of expediency into forsaking our *930commitment to protecting individual liberty and privacy. It was for that very reason that the Framers of the Bill of Rights insisted that law enforcement efforts be permanently and unambiguously restricted in order to preserve personal freedoms. In the constitutional scheme they ordained, the sometimes unpopular task of ensuring that the government’s enforcement efforts remain within the strict boundaries fixed by the Fourth Amendment was entrusted to the courts. As James Madison predicted in his address to the First Congress on June 8, 1789:
“If [these rights] are incorporated into the Constitution, independent tribunals of justice will consider themselves in a peculiar manner the guardians of those rights; they will be an impenetrable bulwark against every assumption of power in the Legislative or Executive; they will be naturally led to resist every encroachment upon rights expressly stipulated for in the Constitution by the declaration of rights.” 1 Annals of Cong. 439.
If those independent tribunals lose their resolve, however, as the Court has done today, and give way to the seductive call of expediency, the vital guarantees of the Fourth Amendment are reduced to nothing more than a “form of words.” Silverthorne Lumber Co. v. United States, 251 U. S. 385, 392 (1920).
A proper understanding of the broad purposes sought to be served by the Fourth Amendment demonstrates that the principles embodied in the exclusionary rule rest upon a far firmer constitutional foundation than the shifting sands of the Court’s deterrence rationale. But even if I were to accept the Court’s chosen method of analyzing the question posed by these cases, I would still conclude that the Court’s decision cannot be justified.
I
The Court holds that physical evidence seized by police officers reasonably relying upon a warrant issued by a de*931tached and neutral magistrate is admissible in the prosecution’s case in chief, even though a reviewing court has subsequently determined either that the warrant was defective, No. 82-963, or that those officers failed to demonstrate when applying for the warrant that there was probable cause to conduct the search, No. 82-1771. I have no doubt that these decisions will prove in time to have been a grave mistake. But, as troubling and important as today’s new doctrine may be for the administration of criminal justice in this country, the mode of analysis used to generate that doctrine also requires critical examination, for it may prove in the long run to pose the greater threat to our civil liberties.
A
At bottom, the Court’s decision turns on the proposition that the exclusionary rule is merely a “‘judicially created remedy designed to safeguard Fourth Amendment rights generally through its deterrent effect, rather than a personal constitutional right.’” Ante, at 906, quoting United States v. Calandra, 414 U. S., at 348. The germ of that idea is found in Wolf v. Colorado, 338 U. S. 25 (1949), and although I had thought that such a narrow conception of the rule had been forever put to rest by our decision in Mapp v. Ohio, 367 U. S. 643 (1961), it has been revived by the present Court and reaches full flower with today’s decision. The essence of this view, as expressed initially in the Calandra opinion and as reiterated today, is that the sole “purpose of the Fourth Amendment is to prevent unreasonable governmental intrusions into the privacy of one’s person, house, papers, or effects. The wrong condemned is the unjustified governmental invasion of these areas of an individual’s life. That wrong . . . is fully accomplished by the original search without probable cause.” 414 U. S., at 354 (emphasis added); see also ante, at 906. This reading of the Amendment implies that its proscriptions are directed solely at those government agents who may actually invade an individual’s constitution*932ally protected privacy. The courts are not subject to any direct constitutional duty to exclude illegally obtained evidence, because the question of the admissibility of such evidence is not addressed by the Amendment. This view of the scope of the Amendment relegates the judiciary to the periphery. Because the only constitutionally cognizable injury has already been “fully accomplished” by the police by the time a case comes before the courts, the Constitution is not itself violated if the judge decides to admit the tainted evidence. Indeed, the most the judge can do is wring his hands and hope that perhaps by excluding such evidence he can deter future transgressions by the police.
Such a reading appears plausible, because, as critics of the exclusionary rule never tire of repeating,2 the Fourth Amendment makes no express provision for the exclusion of evidence secured in violation of its commands. A short answer to this claim, of course, is that many of the Constitution’s most vital imperatives are stated in general terms and the task of giving meaning to these precepts is therefore left to subsequent judicial decisionmaking in the context of concrete cases. The nature of our Constitution, as Chief Justice Marshall long ago explained, “requires that only its great outlines should be marked, its important objects designated, and the minor ingredients which compose those objects be deduced from the nature of the objects themselves.” McCulloch v. Maryland, 4 Wheat. 316, 407 (1819).
A more direct answer may be supplied by recognizing that the Amendment, like other provisions of the Bill of Rights, restrains the power of the government as a whole; it does not specify only a particular agency and exempt all others. The judiciary is responsible, no less than the executive, for ensuring that constitutional rights are respected.
*933When that fact is kept in mind, the role of the courts and their possible involvement in the concerns of the Fourth Amendment comes into sharper focus. Because seizures are executed principally to secure evidence, and because such evidence generally has utility in our legal system only in the context of a trial supervised by a judge, it is apparent that the admission of illegally obtained. evidence implicates the same constitutional concerns as the initial seizure of that evidence. Indeed, by admitting unlawfully seized evidence, the judiciary becomes a part of what is in fact a single governmental action prohibited by the terms of the Amendment.3 Once that connection between the evidence-gathering role of the police and the evidence-admitting function of the courts is acknowledged, the plausibility of the Court’s interpretation becomes more suspect. Certainly nothing in the language or history of the Fourth Amendment suggests that a recognition of this evidentiary link between the police and the courts was meant to be foreclosed.4 It is difficult to give any meaning *934at all to the limitations imposed by the Amendment if they are read to proscribe only certain conduct by the police but to allow other agents of the same government to take advantage of evidence secured by the police in violation of its requirements.5 The Amendment therefore must be read to condemn not only the initial unconstitutional invasion of privacy — which is done, after all, for the purpose of securing evidence — but also the subsequent use of any evidence so obtained.
*935The Court evades this principle by drawing an artificial line between the constitutional rights and responsibilities that are engaged by actions of the police and those that are engaged when a defendant appears before the courts. According to the Court, the substantive protections of the Fourth Amendment are wholly exhausted at the moment when police unlawfully invade an individual’s privacy and thus no substantive force remains to those protections at the time of trial when the government seeks to use evidence obtained by the police.
I submit that such a crabbed reading of the Fourth Amendment casts aside the teaching of those Justices who first formulated the exclusionary rule, and rests ultimately on an impoverished understanding of judicial responsibility in our constitutional scheme. For my part, “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures” comprises a personal right to exclude all evidence secured by means of unreasonable searches and seizures. The right to be free from the initial invasion of privacy and the right of exclusion are coordinate components of the central embracing right to be free from unreasonable searches and seizures.
Such a conception of the rights secured by the Fourth Amendment was unquestionably the original basis of what has come to be called the exclusionary rule when it was first formulated in Weeks v. United States, 232 U. S. 383 (1914). There the Court considered whether evidence seized in violation of the Fourth Amendment by a United States Marshal could be admitted at trial after the defendant had moved that the evidence be returned. Significantly, although the Court considered the Marshal’s initial invasion of the defendant’s home to be unlawful, it went on to consider a question that “involves the right of the court in a criminal prosecution to retain for the purposes of evidence the letters and correspondence of the accused, seized in his house in his absence without his authority, by a United States Marshal holding no *936warrant for . . . the search of his premises.” Id., at 393. In answering that question, Justice Day, speaking for a unanimous Court, expressly recognized that the commands of the Fourth Amendment were addressed to both the courts and the Executive Branch:
“The effect of the Fourth Amendment is to put the courts of the United States and Federal officials, in the exercise of their power and authority, under limitations and restraints as to the exercise of such power and authority, and to forever secure the people, their persons, houses, papers and effects against all unreasonable searches and seizures under the guise of law. This protection reaches all alike, whether accused of crime or not, and the duty of giving to it force and effect is obligatory upon all entrusted under our Federal system with the enforcement of the laws. The tendency of those who execute the criminal laws of the country to obtain conviction by means of unlawful seizures . . . should find no sanction in the judgments of the courts which are charged at all times with the support of the Constitution and to which people of all conditions have a right to appeal for the maintenance of such fundamental rights.” Id., at 391-392.
The heart of the Weeks opinion, and for me the beginning of wisdom about the Fourth Amendment’s proper meaning, is found in the following passage:
“If letters and private documents can ... be seized and held and used in evidence against a citizen accused of an offense, the protection of the Fourth Amendment declaring his right to be secure against such searches and seizures is of no value, and, so far as those thus placed are concerned, might as well be stricken from the Constitution. The efforts of the courts and [federal] officials to bring the guilty to punishment, praiseworthy as they are, are not to be aided by the sacrifice of those great *937principles established by years of endeavor and suffering which have resulted in their embodiment in the fundamental law of the land. The United States Marshal could only have invaded the house of the accused when armed with a warrant issued as required by the Constitution. . . . Instead, he acted without sanction of law, doubtless prompted by the desire to bring further proof to the aid of the Government, and under color of his office undertook to make a seizure of private papers in direct violation of the constitutional prohibition against such action. ... To sanction such proceedings would be to affirm by judicial decision a manifest neglect if not an open defiance of the prohibitions of the Constitution, intended for the protection of the people against such unauthorized action.” Id., at 393-394.
What this passage succinctly captures is the essential recognition, ignored by the present Court, that seizures are generally executed for the purpose of bringing “proof to the aid of the Government,” id., at 393, that the utility of such evidence in a criminal prosecution arises ultimately in the context of the courts, and that the courts therefore cannot be absolved of responsibility for the means by which evidence is obtained. As the Court in Weeks clearly recognized, the obligations cast upon government by the Fourth Amendment are not confined merely to the police. In the words of Justice Holmes: “If the search and seizure are unlawful as invading personal rights secured by the Constitution those rights would be infringed yet further if the evidence were allowed to be used.” Dodge v. United States, 272 U. S. 530, 532 (1926). As the Court further explained in Olmstead v. United States, 277 U. S. 438 (1928):
“The striking outcome of the Weeks case and those which followed it was the sweeping declaration that the Fourth Amendment, although not referring to or limiting the use of evidence in courts, really forbade its introduction if obtained by government officers through a *938violation of the Amendment. Theretofore many had supposed under the ordinary common law rules, if the tendered evidence was pertinent, the method of obtaining it was unimportant. . . . But in the Weeks case, and those which followed, this Court decided with great emphasis, and established as the law for the federal courts, that the protection of the Fourth Amendment would be much impaired unless it was held that not only was the official violator of the rights under the Amendment subject to an action at the suit of the injured defendant, but also that the evidence thereby obtained could not be received.” Id., at 462-463.
That conception of the rule, in my view, is more faithful to the meaning and purpose of the Fourth Amendment and to the judiciary’s role as the guardian of the people’s constitutional liberties. In contrast to the present Court’s restrictive reading, the Court in Weeks recognized that, if the Amendment is to have any meaning, police and the courts cannot be regarded as constitutional strangers to each other; because the evidence-gathering role of the police is directly linked to the evidence-admitting function of the courts, an individual’s Fourth Amendment rights may be undermined as completely by one as by the other.
B
From the foregoing, it is clear why the question whether the exclusion of evidence would deter future police misconduct was never considered a relevant concern in the early cases from Weeks to Olmstead.6 In those formative decisions, the Court plainly understood that the exclusion of illegally obtained evidence was compelled not by judicially fash*939ioned remedial purposes, but rather by a direct constitutional command. A new phase in the history of the rule, however, opened with the Court’s decision in Wolf v. Colorado, 338 U. S. 25 (1949). Although that decision held that the security of one’s person and privacy protected by the Fourth Amendment was “implicit in ‘the concept of ordered liberty’ and as such enforceable against the States through the Due Process Clause” of the Fourteenth Amendment, id., at 27-28, quoting Palko v. Connecticut, 302 U. S. 319, 325 (1937), the Court went on, in what can only be regarded as a tour de force of constitutional obfuscation, to say that the “ways of enforcing such a basic right raise questions of a different order,” 338 U. S., at 28. Notwithstanding the force of the Weeks doctrine that the Fourth Amendment required exclusion, a state court was free to admit illegally seized evidence, according to the Court in Wolf, so long as the State had devised some other “effective” means of vindicating a defendant’s Fourth Amendment rights. 338 U. S., at 31.
Twelve years later, in Mapp v. Ohio, 367 U. S. 643 (1961), however, the Court restored the original understanding of the Weeks case by overruling the holding of Wolf and repudiating its rationale. Although in the course of reaching this conclusion the Court in Mapp responded at certain points to the question, first raised in Wolf, of whether the exclusionary rule was an “effective” remedy compared to alternative means of enforcing the right, see 367 U. S., at 651-653, it nevertheless expressly held that “all evidence obtained by searches and seizures in violation of the Constitution is, by that same authority, inadmissible in a state court.” Id., at 655 (emphasis added). In the Court’s view, the exclusionary rule was not one among a range of options to be selected at the discretion of judges; it was “an essential part of both the Fourth and Fourteenth Amendments.” Id., at 657. Rejection of the Wolf approach was constitutionally required, the Court explained, because “the admission of the new constitutional right by Wolf could not consistently tolerate denial of *940its most important constitutional privilege, namely, the exclusion of the evidence which an accused had been forced to give by reason of the unlawful seizure. To hold otherwise is to grant the right but in reality to withhold its privilege and enjoyment.” 367 U. S., at 656. Indeed, no other explanation suffices to account for the Court’s holding in Mapp, since the only possible predicate for the Court’s conclusion that the States were bound by the Fourteenth Amendment to honor the Weeks doctrine is that the exclusionary rule was “part and parcel of the Fourth Amendment’s limitation upon [governmental] encroachment of individual privacy.” 367 U. S., at 651.7
Despite this clear pronouncement, however, the Court since Calandra has gradually pressed the deterrence rationale for the rule back to center stage. See, e. g., United States v. Peltier, 422 U. S. 531 (1975); United States v. Janis, 428 U. S. 433 (1976); Stone v. Powell, 428 U. S. 465 (1976). The various arguments advanced by the Court in this campaign have only strengthened my conviction that the deterrence theory is both misguided and unworkable. First, *941the Court has frequently bewailed the “cost” of excluding reliable evidence. In large part, this criticism rests upon a refusal to acknowledge the function of the Fourth Amendment itself. If nothing else, the Amendment plainly operates to disable the government from gathering information and securing evidence in certain ways. In practical terms, of course, this restriction of official power means that some incriminating evidence inevitably will go undetected if the government obeys these constitutional restraints. It is the loss of that evidence that is the “price” our society pays for enjoying the freedom and privacy safeguarded by the Fourth Amendment. Thus, some criminals will go free not, in Justice (then Judge) Cardozo’s misleading epigram, “because the constable has blundered,” People v. Defore, 242 N. Y. 13, 21, 150 N. E. 585, 587 (1926), but rather because official compliance with Fourth Amendment requirements makes it more difficult to catch criminals. Understood in this way, the Amendment directly contemplates that some reliable and incriminating evidence will be lost to the government; therefore, it is not the exclusionary rule, but the Amendment itself that has imposed this cost.8
*942In addition, the Court’s decisions over the past decade have made plain that the entire enterprise of attempting to assess the benefits and costs of the exclusionary rule in various contexts is a virtually impossible task for the judiciary to perform honestly or accurately. Although the Court’s language in those cases suggests that some specific empirical basis may support its analyses, the reality is that the Court’s opinions represent inherently unstable compounds of intuition, hunches, and occasional pieces of partial and often inconclusive data. In Calandra, for example, the Court, in considering whether the exclusionary rule should apply in grand jury proceedings, had before it no concrete evidence whatever concerning the impact that application of the rule in such proceedings would have either in terms of the long-term costs or the expected benefits. To the extent empirical data are available regarding the general costs and benefits of the exclusionary rule, such data have shown, on the one hand, as the Court acknowledges today, that the costs are not as substantial as critics have asserted in the past, see ante, at 907-908, n. 6, and, on the other hand, that while the exclusionary rule may well have certain deterrent effects, it is extremely difficult to determine with any degree of precision whether the incidence of unlawful conduct by police is now lower than it was prior to Mapp. See United States v. Janis, 428 U. S., at 449-453, and n. 22; Stone v. Powell, 428 U. S., at 492, n. 32.9 The *943Court has sought to turn this uncertainty to its advantage by casting the burden of proof upon proponents of the rule, see, e. g., United States v. Janis, supra, at 453-454. “Obviously,” however, “the assignment of the burden of proof on an issue where evidence does not exist and cannot be obtained is outcome determinative. [The] assignment of the burden is merely a way of announcing a predetermined conclusion.”10
By remaining within its redoubt of empiricism and by basing the rule solely on the deterrence rationale, the Court has robbed the rule of legitimacy. A doctrine that is explained as if it were an empirical proposition but for which there is only limited empirical support is both inherently unstable and an easy mark for critics. The extent of this Court’s fidelity to Fourth Amendment requirements, however, should not turn on such statistical uncertainties. I share the view, expressed by Justice Stewart for the Court in Faretta v. California, 422 U. S. 806 (1975), that “[pjersonal liberties are not rooted in the law of averages.” Id., at 834. Rather than seeking to give effect to the liberties secured by the Fourth Amendment through guesswork about deterrence, the Court should restore to its proper place the principle framed 70 years ago in Weeks that an individual whose privacy has been invaded in violation of the Fourth Amendment has a right grounded in that Amendment to prevent the government from subsequently making use of any evidence so obtained.
*944H-t HH
Application of that principle clearly requires affirmance m the two cases decided today. In the first, United States v. Leon, No. 82-1771, it is conceded by the Government and accepted by the Court that the affidavit filed by the police officers in support of their application for a search warrant failed to provide a sufficient basis on which a neutral and detached magistrate could conclude that there was probable cause to issue the warrant. Specifically, it is conceded that the officers’ application for a warrant was based in part on information supplied by a confidential informant of unproven reliability that was over five months old by the time it was relayed to the police. Although the police conducted an independent investigation on the basis of this tip, both the District Court and the Court of Appeals concluded that the additional information gathered by the officers failed to corroborate the details of the informant’s tip and was “as consistent with innocence as . . . with guilt.” App. to Pet. for Cert. 10a. The warrant, therefore, should never have issued. Stripped of the authority of the warrant, the conduct of these officers was plainly unconstitutional — it amounted to nothing less than a naked invasion of the privacy of respondents’ homes without the requisite justification demanded by the Fourth Amendment. In order to restore the Government to the position it would have occupied had this unconstitutional search not occurred, therefore, it was necessary that the evidence be suppressed. As we said in Coolidge v. New Hampshire, 403 U. S. 443 (1971), the Warrant Clause is not “an inconvenience to be somehow ‘weighed’ against the claims of police efficiency. It is, or should be, an important working part of our machinery of government, operating as a matter of course to check the ‘well-intentioned but mistakenly overzealous executive officers’ who are part of any system of law enforcement.” Id., at 481 (footnote omitted).
A close examination of the facts of this case reveals that this is neither an extraordinary nor indeed a very costly step. *945The warrant had authorized a search for cocaine, methaqua-lone tablets, and miscellaneous narcotics paraphernalia at several locations: a condominium at 7902 Via Magdalena in Los Angeles; a residence at 620 Price Drive in Burbank; a residence at 716 South Sunset Canyon in Burbank; and four automobiles owned respectively by respondents Leon, Sanchez, Stewart, and Del Castillo. App. 31-33. Pursuant to this warrant, the officers seized approximately four pounds of cocaine and over 1,000 methaqualone tablets from the Via Magdalena condominium, nearly one pound of cocaine from the Sunset Canyon residence, about an ounce of cocaine from the Price Drive residence, and certain paraphernalia from Del Castillo’s and Stewart’s automobiles. On the basis of this and other evidence, the four respondents were charged with violating 21 U. S. C. § 846 for conspiring to possess and distribute cocaine, and § 841(a)(1) for possessing methaqua-lone and cocaine with intent to distribute. The indictment specifically alleged that respondents had maintained the Via Magdalena condominum as a storage area for controlled substances which they distributed to prospective purchasers. App. 27-28.
At the suppression hearing, the District Court determined that none of the respondents had a sufficient expectation of privacy to contest the search of the Via Magdalena condominium, that respondents Stewart and Sanchez could challenge the search of their home at Price Drive, that respondent Leon was entitled to challenge the search of his home at Sunset Canyon, and that respondents Del Castillo and Stewart could contest the search of their cars. Given its finding that probable cause to issue the warrant was lacking, the District Court ruled that the evidence from the Price Drive residence could not be used against respondents Stewart and Sanchez, that evidence from the Sunset Canyon residence could not be used against Leon, and that evidence obtained from both Del Castillo’s and Stewart’s automobiles could not be used against them. App. to Pet. for Cert. 10a-13a.
*946The tenor of the Court’s opinion suggests that this order somehow imposed a grave and presumably unjustifiable cost on society. Such a suggestion, however, is a gross exaggeration. Since the indictment focused upon a conspiracy among all respondents to use the Via Magdalena condominium as a storage area for controlled substances, and since the bulk of the evidence seized was from that condominium and was plainly admissible under the District Court’s order, the Government would clearly still be able to present a strong case to the jury following the court’s suppression order. I emphasize these details not to suggest how the Government’s case would fare before the jury but rather to clarify a point that is lost in the Court’s rhetorical excesses over the costs of the exclusionary rule — namely, that the suppression of evidence will certainly tend to weaken the Government’s position but it will rarely force the Government to abandon a prosecution. Cf. infra, at 950-951, and n. 11. In my view, a doctrine that preserves intact the constitutional rights of the accused, and, at the same time, is sufficiently limited to permit society’s legitimate and pressing interest in criminal law enforcement to be served should not be so recklessly discarded. It is a doctrine that gives life to the “very heart of the Fourth Amendment directive: that... a governmental search and seizure should represent both the efforts of the officer to gather evidence of wrongful acts and the judgment of the magistrate that the collected evidence is sufficient to justify invasion of a citizen’s private premises.” United States v. United States District Court, 407 U. S. 297, 316 (1972).
In the second case before the Court, Massachusetts v. Sheppard, No. 82-963, the State concedes and the Court accepts that the warrant issued to search respondent’s home completely failed to state with particularity the things to be seized. Indeed, the warrant expressly and particularly described things such as “controlled substance[s]” and “other paraphernalia used in, for, or in connection with the unlawful possession or use of any controlled substance” that the police had no reason whatsoever to believe were to be found in *947respondent’s home. App. 17a. Given the Fourth Amendment’s requirement that “no Warrants shall issue, but upon probable cause . . . and particularly describing the . . . things to be seized,” this warrant should never have been issued. The police who entered respondent’s home, therefore, were without constitutional authority to do so.
Although the Court’s opinion tends to overlook this fact, the requirement of particularity is not a mere “technicality,” it is an express constitutional command. Ybarra v. Illinois, 444 U. S. 85, 92 (1979); Lo-Ji Sales, Inc. v. New York, 442 U. S. 319 (1979); Stanford v. Texas, 379 U. S. 476 (1965); Marron v. United States, 275 U. S. 192, 196 (1927). The purpose of that requirement is to prevent precisely the kind of governmental conduct that the faulty warrant at issue here created a grave risk of permitting — namely, a search that was not narrowly and particularly limited to the things that a neutral and detached magistrate had reason to believe might be found at respondent’s home. Although it is true, as Justice Stevens observes, see post, at 964, that the affidavit submitted by the police set forth with particularity those items that they sought authority to search for, it is nevertheless clear that the warrant itself — the document which actually gave the officers legal authority to invade respondent’s privacy — made no mention of these items. And, although it is true that the particular officers who applied for the warrant also happened to execute it and did so in accordance with the limits proposed in their affidavit, this happenstance should have no bearing on the central question whether these officers secured that prior judicial authority to conduct their search required by the Fourth Amendment. As we made clear in United States v. United States District Court, supra, at 317 (footnote omitted), “[t]he Fourth Amendment contemplates a prior judicial judgment, not the risk that executive discretion may be reasonably exercised.” See also Katz v. United States, 389 U. S. 347, 356-357 (1967) (“this Court has never sustained a search upon the sole ground that officers reasonably expected to find evidence of a particular crime *948and voluntarily confined their activities to the least intrusive means consistent with that end”). Had the warrant actually been enforced by officers other than those who prepared the affidavit, the same result might not have occured; indeed, the wholly erroneous nature of the warrant might have led such officers to feel at liberty to roam throughout respondent’s home in search of drugs. Cf. Whiteley v. Warden, 401 U. S. 560 (1971). I therefore fail to see how a search pursuant to such a fundamentally defective warrant can be characterized as “reasonable.”
What the Framers of the Bill of Rights sought to accomplish through the express requirements of the Fourth Amendment was to define precisely the conditions under which government agents could search private property so that citizens would not have to depend solely upon the discretion and restraint of those agents for the protection of their privacy. Although the self-restraint and care exhibited by the officers in this case is commendable, that alone can never be a sufficient protection for constitutional liberties. I am convinced that it is not too much to ask that an attentive magistrate take those minimum steps necessary to ensure that every warrant he issues describes with particularity the things that his independent review of the warrant application convinces him are likely to be found in the premises. And I am equally convinced that it is not too much to ask that well-trained and experienced police officers take a moment to check that the warrant they have been issued at least describes those things for which they have sought leave to search. These convictions spring not from my own view of sound criminal law enforcement policy, but are instead compelled by the language of the Fourth Amendment and the history that led to its adoption.
Ill
Even if I were to accept the Court’s general approach to the exclusionary rule, I could not agree with today’s result. *949There is no question that in the hands of the present Court the deterrence rationale has proved to be a powerful tool for confining the scope of the rule. In Calandra, for example, the Court concluded that the “speculative and undoubtedly minimal advance in the deterrence of police misconduct,” was insufficient to outweigh the “expense of substantially impeding the role of the grand jury.” 414 U. S., at 351-352. In Stone v. Powell, the Court found that “the additional contribution, if any, of the consideration of search-and-seizure claims of state prisoners on collateral review is small in relation to the costs.” 428 U. S., at 493. In United States v. Janis, 428 U. S. 433 (1976), the Court concluded that “exclusion from federal civil proceedings of evidence unlawfully seized by a state criminal enforcement officer has not been shown to have a sufficient likelihood of deterring the conduct of the state police so that it outweighs the societal costs imposed by the exclusion.” Id., at 454. And in an opinion handed down today, the Court finds that the “balance between costs and benefits comes out against applying the exclusionary rule in civil deportation hearings held by the [Immigration and Naturalization Service].” INS v. Lopez-Mendoza, post, at 1050.
Thus, in this bit of judicial stagecraft, while the sets sometimes change, the actors always have the same lines. Given this well-rehearsed pattern, one might have predicted with some assurance how the present case would unfold. First there is the ritual incantation of the “substantial social costs” exacted by the exclusionary rule, followed by the virtually foreordained conclusion that, given the marginal benefits, application of the rule in the circumstances of these cases is not warranted. Upon analysis, however, such a result cannot be justified even on the Court’s own terms.
At the outset, the Court suggests that society has been asked to pay a high price — in terms either of setting guilty persons free or of impeding the proper functioning of trials— as a result of excluding relevant physical evidence in cases *950where the police, in conducting searches and seizing evidence, have made only an “objectively reasonable” mistake concerning the constitutionality of their actions. See ante, at 907-908. But what evidence is there to support such a claim?
Significantly, the Court points to none, and, indeed, as the Court acknowledges, see ante, at 907-908, n. 6, recent studies have demonstrated that the “costs” of the exclusionary rule — calculated in terms of dropped prosecutions and lost convictions — are quite low. Contrary to the claims of the rule’s critics that exclusion leads to “the release of countless guilty criminals,” Bivens v. Six Unknown Federal Narcotics Agents, 403 U. S. 388, 416 (1971) (Burger, C. J., dissenting), these studies have demonstrated that federal and state prosecutors very rarely drop cases because of potential search and seizure problems. For example, a 1979 study prepared at the request of Congress by the General Accounting Office reported that only 0.4% of all cases actually declined for prosecution by federal prosecutors were declined primarily because of illegal search problems. Report of the Comptroller General of the United States, Impact of the Exclusionary Rule on Federal Criminal Prosecutions 14 (1979). If the GAO data are restated as a percentage of all arrests, the study shows that only 0.2% of all felony arrests are declined for prosecution because of potential exclusionary rule problems. See Davies, A Hard Look at What We Know (and Still Need to Learn) About the “Costs” of the Exclusionary Rule: The NIJ Study and Other Studies of “Lost” Arrests, 1983 A. B. F. Res. J. 611, 635.11 Of course, these data de*951scribe only the costs attributable to the exclusion of evidence in all cases; the costs due to the exclusion of evidence in the narrower category of cases where police have made objectively reasonable mistakes must necessarily be even smaller. The Court, however, ignores this distinction and mistakenly weighs the aggregated costs of exclusion in all cases, irrespective of the circumstances that led to exclusion, see ante, at 907, against the potential benefits associated with only those cases in which evidence is excluded because police reasonably but mistakenly believe that their conduct does not violate the Fourth Amendment, see ante, at 915-921. When such faulty scales are used, it is little wonder that the balance tips in favor of restricting the application of the rule.
*952What then supports the Court’s insistence that this evidence be admitted? Apparently, the Court’s only answer is that even though the costs of exclusion are not very substantial, the potential deterrent effect in these circumstances is so marginal that exclusion cannot be justified. The key to the Court’s conclusion in this respect is its belief that the prospective deterrent effect of the exclusionary rule operates only in those situations in which police officers, when deciding whether to go forward with some particular search, have reason to know that their planned conduct will violate the requirements of the Fourth Amendment. See ante, at 919-921. If these officers in fact understand (or reasonably should understand because the law is well settled) that their proposed conduct will offend the Fourth Amendment and that, consequently, any evidence they seize will be suppressed in court, they will refrain from conducting the planned search. In those circumstances, the incentive system created by the exclusionary rule will have the hoped-for deterrent effect. But in situations where police officers reasonably (but mistakenly) believe that their planned conduct satisfies Fourth Amendment requirements — presumably either (a) because they are acting on the basis of an apparently valid warrant, or (b) because their conduct is only later determined to be invalid as a result of a subsequent change in the law or the resolution of an unsettled question of law — then such officers will have no reason to refrain from conducting the search and the exclusionary rule will have no effect.
At first blush, there is some logic to this position. Undoubtedly, in the situation hypothesized by the Court, the existence of the exclusionary rule cannot be expected to have any deterrent effect on the particular officers at the moment they are deciding whether to go forward with the search. Indeed, the subsequent exclusion of any evidence seized under such circumstances appears somehow “unfair” to the particular officers involved. As the Court suggests, these officers have acted in what they thought was an appropriate *953and constitutionally authorized manner, but then the fruit of their efforts is nullified by the application of the exclusionary rule. Ante, at 920-921.
The flaw in the Court’s argument, however, is that its logic captures only one comparatively minor element of the generally acknowledged deterrent purposes of the exclusionary rule. To be sure, the rule operates to some extent to deter future misconduct by individual officers who have had evidence suppressed in their own cases. But what the Court overlooks is that the deterrence rationale for the rule is not designed to be, nor should it be thought of as, a form of “punishment” of individual police officers for their failures to obey the restraints imposed by the Fourth Amendment. See United States v. Peltier, 422 U. S., at 556-557 (Brennan, J., dissenting). Instead, the chief deterrent function of the rule is its tendency to promote institutional compliance with Fourth Amendment requirements on the part of law enforcement agencies generally.12 Thus, as the Court has previ*954ously recognized, “over the long term, [the] demonstration [provided by the exclusionary rule] that our society attaches serious consequences to violation of constitutional rights is thought to encourage those who formulate law enforcement policies, and the officers who implement them, to incorporate Fourth Amendment ideals into their value system.” Stone v. Powell, 428 U. S., at 492. It is only through such an in-stitutionwide mechanism that information concerning Fourth Amendment standards can be effectively communicated to rank-and-file officers.13
*955If the overall educational effect of the exclusionary rule is considered, application of the rule to even those situations in which individual police officers have acted on the basis of a reasonable but mistaken belief that their conduct was authorized can still be expected to have a considerable long-term deterrent effect. If evidence is consistently excluded in these circumstances, police departments will surely be prompted to instruct their officers to devote greater care and attention to providing sufficient information to establish probable cause when applying for a warrant, and to review with some attention the form of the warrant that they have been issued, rather than automatically assuming that whatever document the magistrate has signed will necessarily comport with Fourth Amendment requirements.
After today’s decisions, however, that institutional incentive will be lost. Indeed, the Court’s “reasonable mistake” exception to the exclusionary rule will tend to put a premium on police ignorance of the law. Armed with the assurance provided by today’s decisions that evidence will always be admissible whenever an officer has “reasonably” relied upon a warrant, police departments will be encouraged to train officers that if a warrant has simply been signed, it is reasonable, without more, to rely on it. Since in close cases there will no longer be any incentive to err on the side of constitutional behavior, police would have every reason to adopt a “let’s-wait-until-it’s-decided” approach in situations in which there is a question about a warrant’s validity or the basis for its issuance. Cf. United States v. Johnson, 457 U. S. 537, 561 (1982).14
*956Although the Court brushes these concerns aside, a host of grave consequences can be expected to result from its decision to carve this new exception out of the exclusionary rule. A chief consequence of today’s decisions will be to convey a clear and unambiguous message to magistrates that their decisions to issue warrants are now insulated from subsequent judicial review. Creation of this new exception for good-faith reliance upon a warrant implicitly tells magistrates that they need not take much care in reviewing warrant applications, since their mistakes will from now on have virtually no consequence: If their decision to issue a warrant was correct, the evidence will be admitted; if their decision was incorrect but the police relied in good faith on the warrant, the evidence will also be admitted. Inevitably, the care and attention devoted to such an inconsequential chore will dwindle. Although the Court is correct to note that magistrates do not share the same stake in the outcome of a criminal case as the police, they nevertheless need to appreciate that their role is of some moment in order to continue performing the important task of carefully reviewing warrant applications. Today’s decisions effectively remove that incentive.15
*957Moreover, the good-faith exception will encourage police to provide only the bare minimum of information in future warrant applications. The police will now know that if they can secure a warrant, so long as the circumstances of its issuance are not “entirely unreasonable,” ante, at 923, all police conduct pursuant to that warrant will be protected from further judicial review.16 The clear incentive that operated in the past to establish probable cause adequately because reviewing courts would examine the magistrate’s judgment carefully, see, e. g., Franks v. Delaware, 438 U. S. 154, 169-170 (1978); Jones v. United States, 362 U. S. 257, 271-272 (1960); Giordenello v. United States, 357 U. S. 480, 483 (1958), has now been so completely vitiated that the police need only show that it was not “entirely unreasonable” under the cir*958cumstances of a particular case for them to believe that the warrant they were issued was valid. See ante, at 923. The long-run effect unquestionably will be to undermine the integrity of the warrant process.
Finally, even if one were to believe, as the Court apparently does, that police are hobbled by inflexible and hyper-technical warrant procedures, today’s decisions cannot be justified. This is because, given the relaxed standard for assessing probable cause established just last Term in Illinois v. Gates, 462 U. S. 213 (1983), the Court’s newly fashioned good-faith exception, when applied in the warrant context, will rarely, if ever, offer any greater flexibility for police than the Gates standard already supplies. In Gates, the Court held that “[t]he task of the issuing magistrate is simply to make a practical, common-sense decision whether, given all the circumstances set forth in the affidavit before him, . . . there is a fair probability that contraband or evidence of a crime will be found in a particular place.” Id., at 238. The task of a reviewing court is confined to determining whether “the magistrate had a ‘substantial basis for . . . concluding]’ that probable cause existed.” Ibid. Given such a relaxed standard, it is virtually inconceivable that a reviewing court, when faced with a defendant’s motion to suppress, could first find that a warrant was invalid under the new Gates standard, but then, at the same time, find that a police officer’s reliance on such an invalid warrant was nevertheless “objectively reasonable” under the test announced today.17 Because the two standards overlap so completely, it is unlikely that a warrant could be found invalid under Gates and yet the police reliance upon it could be seen as objectively reasonable; otherwise, we would have to entertain the mind-*959boggling concept of objectively reasonable reliance upon an objectively unreasonable warrant.
This paradox, as Justice Stevens suggests, see post, at 961-962, perhaps explains the Court’s unwillingness to remand No. 82-1771 for reconsideration in light of Gates, for it is quite likely that on remand the Court of Appeals would find no violation of the Fourth Amendment, thereby demonstrating that the supposed need for the good-faith exception in this context is more apparent than real. Therefore, although the Court’s decisions are clearly limited to the situation in which police officers reasonably rely upon an apparently valid warrant in conducting a search, I am not at all confident that the exception unleashed today will remain so confined. Indeed, the full impact of the Court’s regrettable decisions will not be felt until the Court attempts to extend this rule to situations in which the police have conducted a warrantless search solely on the basis of their own judgment about the existence of probable cause and exigent circumstances. When that question is finally posed, I for one will not be surprised if my colleagues decide once again that we simply cannot afford to protect Fourth Amendment rights.
IV
When the public, as it quite properly has done in the past as well as in the present, demands that those in government increase their efforts to combat crime, it is all too easy for those government officials to seek expedient solutions. In contrast to such costly and difficult measures as building more prisons, improving law enforcement methods, or hiring more prosecutors and judges to relieve the overburdened court systems in the country’s metropolitan areas, the relaxation of Fourth Amendment standards seems a tempting, costless means of meeting the public’s demand for better law enforcement. In the long run, however, we as a society pay a heavy price for such expediency, because as Justice Jackson observed, the rights guaranteed in the Fourth Amendment *960“are not mere second-class rights but belong in the catalog of indispensable freedoms.” Brinegar v. United States, 338 U. S. 160, 180 (1949) (dissenting opinion). Once lost, such rights are difficult to recover. There is hope, however, that in time this or some later Court will restore these precious freedoms to their rightful place as a primary protection for our citizens against overreaching officialdom.
I dissent.

[This opinion applies also to No. 82-963, Massachusetts v. Sheppard, post, p. 981.]

 See, e. g., United States v. Peltier, 422 U. S. 531, 544 (1975) (Brennan, J., dissenting); United States v. Janis, 428 U. S. 433, 460 (1976) (Brennan, J., dissenting); Stone v. Powell, 428 U. S. 465, 502 (1976) (Brennan, J., dissenting); Michigan v. DeFillippo, 443 U. S. 31, 41 (1979) (Brennan, J., dissenting); United States v. Havens, 446 U. S. 620, 629 (1980) (Brennan, J., dissenting).

 See, e. g., Wilkey, The Exclusionary Rule: Why Suppress Valid Evidence?, 62 Judicature 215 (1978); S. Sehlesinger, Exclusionary Injustice (1977).

 In deciding to enforce the exclusionary rule as a matter of state law, the California Supreme Court clearly recognized this point:
“When, as in the present case, the very purpose of an illegal search and seizure is to get evidence to introduce at a trial, the success of the lawless venture depends entirely on the court’s lending its aid by allowing the evidence to be introduced. It is no answer to say that a distinction should be drawn between the government acting as law enforcer and the gatherer of evidence and the government acting as judge.” People v. Cahan, 44 Cal. 2d 434, 445, 282 P. 2d 905, 912 (1955).
For a thoughtful examination of this point, see Schrock & Welsh, Up from Calandra: The Exclusionary Rule as a Constitutional Requirement, 59 Minn. L. Rev. 251, 289-307 (1974).

 Examination of the early state declarations of rights which formed the models for the Fourth Amendment reveals that they were aimed as much at explicitly limiting the manner in which government could gather evidence as at protecting individual privacy. For example, the Massachusetts Constitution of 1780 provided:
“Every subject has a right to be secure from all unreasonable searches, and seizures, of his person, his houses, his papers, and his possessions. All warrants, therefore, are contrary to this right, if the cause or founda*934tion of them be not previously supported by oath or affirmation; and if the order in the warrant to a civil Officer, to make search in suspected places, or to arrest one or more suspected persons, or to seize their property, be not accompanied with a special designation of the persons or objects of search, arrest, or seizure: and no warrant ought to be issued, but in eases, and with the formalities prescribed by the laws.” Art. XIV of the Declaration of Rights of 1780.
See generally T. Taylor, Two Studies in Constitutional Interpretation 41-43 (1969); N. Lasson, The History and Development of the Fourth Amendment to the United States Constitution 51-105 (1970); J. Lanynski, Search and Seizure and the Supreme Court: A Study in Constitutional Interpretation 30-48 (1966); Stewart, The Road to Mapp v. Ohio and Beyond: The Origins, Development, and Future of the Exclusionary Rule in Search- and-Seizure Cases, 83 Colum. L. Rev. 1365, 1369 (1983).

 In Silverthorne Lumber Co. v. United States, 251 U. S. 385 (1920), the Court expressly recognized this point in rejecting the Government’s contention that it should be permitted to make use of knowledge obtained in violation of the Fourth Amendment:
“The Government now while in form repudiating and condemning the illegal seizure, seeks to maintain its right to avail itself of the knowledge obtained by that means which otherwise it would not have had.
“The proposition could not be presented more nakedly. It is that although of course its seizure was an outrage which the Government now regrets, it may study the papers before it returns them, copy them, and then may use the knowledge that it has gained to call upon the owners in a more regular form to produce them .... In our opinion such is not the law. It reduces the Fourth Amendment to a form of words. The essence of a provision forbidding the acquisition of evidence in a certain way is that not merely evidence so acquired shall not be used before the Court but that it shall not be used at all.” Id., at 391-392 (citations omitted) (emphasis added).

 See generally Kamisar, Does (Did) (Should) The Exclusionary Rule Rest on a “Principled Basis” Rather than an “Empirical Proposition”?, 16 Creighton L. Rev. 566, 598-599 (1983); Mertens & Wasserstrom, The Good Faith Exception to the Exclusionary Rule: Deregulating the Police and Derailing the Law, 70 Geo. L. J. 365, 379-380 (1981).

 Indeed, the Court in Mapp expressly noted that the “factual considerations” raised in Wolf concerning the effectiveness of alternative remedies “are not basically relevant to a decision that the exclusionary rule is an essential ingredient of the Fourth Amendment.” 367 U. S., at 651. It is true that in Linkletter v. Walker, 381 U. S. 618 (1965), in holding that Mapp was not to be applied retroactively, the Court described the exclusionary rule as the “only effective deterrent to lawless police action,” 381 U. S., at 636, thereby suggesting that the rule rested on a deterrence rationale. But, as I have explained on another occasion, “[t]he emphasis upon deterrence in Linkletter must be understood in the light of the crucial fact that the States had justifiably relied from 1949 to 1961 upon Wolf. . . , and consequently, that application of Mapp would have required the wholesale release of innumerable convicted prisoners, few of whom could have been successfully retried. In that circumstance, Linkletter held not only that retrospective application of Mapp would not further the goal of deterrence but also that it would not further ‘the administration of justice and the integrity of the judicial process.’ 381 U. S., at 637.” United States v. Calandra, 414 U. S. 338, 359-360 (1974) (dissenting opinion).

 Justice Stewart has explained this point in detail in a recent article:
“Much of the criticism leveled at the exclusionary rule is misdirected; it is more properly directed at the Fourth Amendment itself. It is true that, as many observers have charged, the effect of the rule is to deprive the courts of extremely relevant, often direct evidence of the guilt of the defendant. But these same critics fail to acknowledge that, in many instances, the same extremely relevant evidence would not have been obtained had the police officer complied with the commands of the fourth amendment in the first place. . . .
. . The exclusionary rule places no limitations on the actions of the police. The fourth amendment does. The inevitable result of the Constitution’s prohibition against unreasonable searches and seizures and its requirement that no warrant shall issue but upon probable cause is that police officers who obey its strictures will catch fewer criminals. . . . [T]hat is the price the framers anticipated and were willing to pay to ensure the sanctity of the person, the home, and property against *942unrestrained governmental power.” Stewart, 83 Colum. L. Rev., at 1392-1393.
See also Dellinger, Of Rights and Remedies: The Constitution as a Sword, 85 Harv. L. Rev. 1532, 1563 (1972) (“Under the exclusionary rule a court attempts to maintain the status quo that would have prevailed if the constitutional requirement had been obeyed”).

 See generally on this point, Davies, A Hard Look at What We Know (and Still Need to Learn) About the “Costs” of the Exclusionary Rule: The NIJ Study and Other Studies of “Lost” Arrests, 1983 A. B. F. Res. J. 611, 627-629; Canon, Ideology and Reality in the Debate over the Exclusionary Rule: A Conservative Argument for its Retention, 23 S. Tex. L. J. 559, 561-563 (1982); Critique, On the Limitations of Empirical Evaluations of *943the Exclusionary Rule: A Critique of the Spiotto Research and United States v. Calandra, 69 Nw. U. L. Rev. 740 (1974).

Dworkin, Fact Style Adjudication and the Fourth Amendment: The Limits of Lawyering, 48 Ind. L. J. 329, 332-333 (1973). See also White, Forgotten Points in the “Exclusionary Rule” Debate, 81 Mich. L. Rev. 1273, 1281-1282 (1983) (balancing of deterrent benefits and costs is an “inquiry [that] can never be performed in an adequate way and the reality is thus that the decision must rest not upon those grounds, but upon prior dispositions or unarticulated intuitions that are never justified”); Canon, supra, at 564; Kamisar, 16 Creighton L. Rev., at 646.

 In a series of recent studies, researchers have attempted to quantify the actual costs of the rule. A recent National Institute of Justice study based on data for the 4-year period 1976-1979 gathered by the California Bureau of Criminal Statistics showed that 4.8% of all cases that were declined for prosecution by California prosecutors were rejected because of illegally seized evidence. National Institute of Justice, Criminal Justice Research Report — The Effects of the Exclusionary Rule: A Study in Cali-*951fomia 1 (1982). However, if these data are calculated as a percentage of all arrests, they show that only 0.8% of all arrests were rejected for prosecution because of illegally seized evidence. See Davies, 1983 A. B. F. Res. J., at 619.
In another measure of the rule’s impact — the number of prosecutions that are dismissed or result in acquittals in cases where evidence has been excluded — the available data again show that the Court’s past assessment of the rule’s costs has generally been exaggerated. For example, a study based on data from nine midsized counties in Illinois, Michigan, and Pennsylvania reveals that motions to suppress physical evidence were filed in approximately 5% of the 7,500 cases studied, but that such motions were successful in only 0.7% of all these cases. Nardulli, The Societal Cost of the Exclusionary Rule: An Empirical Assessment, 1983 A. B. F. Res. J. 585, 596. The study also shows that only 0.6% of all cases resulted in acquittals because evidence had been excluded. Id., at 600. In the GAO study, suppression motions were filed in 10.5% of all federal criminal cases surveyed, but of the motions filed, approximately 80-90% were denied. GAO Report, at 8,10. Evidence was actually excluded in only 1.3% of the cases studied, and only 0.7% of all cases resulted in acquittals or dismissals after evidence was excluded. Id., at 9-11. See Davies, supra, at 660. And in another study based on data from cases during 1978 and 1979 in San Diego and Jacksonville, it was shown that only 1% of all cases resulting in nonconvietion were caused by illegal searches. F. Feeney, F. Dill, & A. Weir, Arrests Without Conviction: How Often They Occur and Why (National Institute of Justice 1983). See generally Davies, supra, at 663.

 As Justice Stewart has observed:
“[T]he exclusionary rule is not designed to serve a specific deterrence function; that is, it is not designed to punish the particular police officer for violating a person’s fourth amendment rights. Instead, the rule is designed to produce a ‘systematic deterrence’: the exclusionary rule is intended to create an incentive for law enforcement officials to establish procedures by which police officers are trained to comply with the fourth amendment because the purpose of the criminal justice system — bringing criminals to justice — can be achieved only when evidence of guilt may be used against defendants.” Stewart, 83 Colum. L. Rev., at 1400.
See also Oaks, Studying the Exclusionary Rule in Search and Seizure, 37 U. Chi. L. Rev. 665, 709-710 (1970) (“The exclusionary rule is not aimed at special deterrence since it does not impose any direct punishment on a law enforcement official who has broken the rule. . . . The exclusionary rule is aimed at affecting the wider audience of all law enforcement officials and society at large. It is meant to discourage violations by individuals who have never experienced any sanction for them”); Mertens & Wasserstrom, 70 Geo. L. J., at 399-401; Kamisar, 16 Creighton L. Rev., at 597, n. 204.

Although specific empirical data on the systemic deterrent effect of the rule are not conclusive, the testimony of those actually involved in law enforcement suggests that, at the very least, the Mapp decision had the effect of increasing police awareness of Fourth Amendment requirements and of prompting prosecutors and police commanders to work towards educating rank-and-file officers. For example, as former New York Police Commissioner Murphy explained the impact of the Mapp decision: “I can think of no decision in recent times in the field of law enforcement which had such a dramatic and traumatic effect.... I was immediately caught up in the entire program of reevaluating our procedures, which had followed the Defore rule, and modifying, amending, and creating new policies and new instructions for the implementation of Mapp. . . . Retraining sessions had to be held from the very top administrators down to each of the thousands of foot patrolmen.” Murphy, Judicial Review of Police Methods in Law Enforcement: The Problem of Compliance by Police Departments, 44 Texas L. Rev. 939, 941 (1966).
Further testimony about the impact of the Mapp decision can be found in the statement of Deputy Commissioner Reisman: “The Mapp case was a shock to us. We had to reorganize our thinking, frankly. Before this, nobody bothered to take out search warrants. Although the U. S. Constitution requires warrants in most cases, the U. S. Supreme Court had ruled that evidence obtained without a warrant — illegally, if you will — was admissible in state courts. So the feeling was, why bother? Well, once that rule was changed we knew we had better start teaching our men about it.” N. Y. Times, Apr. 28, 1965, p. 50, col. 1. A former United States Attorney and now Attorney General of Maryland, Stephen Sachs, has described the impact of the rule on police practices in similar terms: “I have watched the rule deter, routinely, throughout my years as a prosecutor. . . . [P]olice-prosecutor consultation is customary in all our cases when Fourth Amendment concerns arise. ... In at least three Maryland *955jurisdictions, for example, prosecutors are on twenty-four hour call to field search and seizure questions presented by police officers.” Sachs, The Exclusionary Rule: A Prosecutor’s Defense, 1 Crim. Justice Ethics 28, 30 (Summer/Fall 1982). See also LaFave, The Fourth Amendment in an Imperfect World: On Drawing “Bright Lines” and “Good Faith,” 43 U. Pitt. L. Rev. 307, 319 (1982); Mertens & Wasserstrom, supra, at 394-401.

The authors of a recent study of the warrant process in seven cities concluded that application of a good-faith exception where an officer relies *956upon a warrant “would further encourage police officers to seek out the less inquisitive magistrates and to rely on boilerplate formulae, thereby lessening the value of search warrants overall. Consequently, the benefits of adoption of a broad good faith exception in terms of a few additional prosecutions appears to be outweighed by the harm to the quality of the entire search warrant process and the criminal justice system in general.” R. Van Duizend, L. Sutton, & C. Carter, The Search Warrant Process: Preconceptions, Perceptions, and Practices 8-12 (Review Draft, National Center for State Courts, 1983). See also Stewart, 83 Colum. L. Rev., at 1403.

 Just last Term in Illinois v. Gates, 462 U. S. 213 (1983), the Court noted:
“Sufficient information must be presented to the magistrate to allow that official to determine probable cause; his action cannot be a mere ratification of the bare conclusions of others. In order to ensure that such an abdication of the magistrate’s duty does not occur, courts must continue to *957conseientiously review the sufficiency of affidavits on which warrants are issued.” Id., at 239.
After today’s decisions, there will be little reason for reviewing courts to conduct such a conscientious review; rather, these courts will be more likely to focus simply on the question of police good faith. Despite the Court’s confident prediction that such review will continue to be conducted, see ante, at 924-925, it is difficult to believe that busy courts faced with heavy dockets will take the time to render essentially advisory opinions concerning the constitutionality of the magistrate’s decision before considering the officer’s good faith.

 As the Court of Appeals for the Second Circuit has observed in this regard:
“If a magistrate’s issuance of a warrant were to be, as the government would have it, an all but conclusive determination of the validity of the search and of the admissibility of the evidence seized thereby, police officers might have a substantial incentive to submit their warrant applications to the least demanding magistrates, since once the warrant was issued, it would be exceedingly difficult later to exclude any evidence seized in the resulting search even if the warrant was issued without probable cause. . . . For practical purposes, therefore, the standard of probable cause might be diluted to that required by the least demanding official authorized to issue warrants, even if this fell well below what the Fourth Amendment required.” United States v. Karathanos, 531 F. 2d 26, 34 (1976).

 See Kamisar, Gates, “Probable Cause,” “Good Faith,” and Beyond, 69 Iowa L. Rev. 551, 588-589 (1984); Wasserstrom, The Incredible Shrinking Fourth Amendment, 21 Am. Crim. L. Rev. 257 (1984); LaFave, 43 U. Pitt. L. Rev., at 307.