Court Opinion

ID: 9429233
Source: CourtListenerOpinion
Date Created: 2023-08-02 23:26:06.846954+00
Date Added: 2024-06-11T17:23:18.071970
License: Public Domain

Justice White,
concurring in the judgment.
In my view, the question regarding modification of the exclusionary rule framed in our order of November 29, 1982, 459 U. S. 1028 (1982), is properly before us and should be addressed. I continue to believe that the exclusionary rule is an inappropriate remedy where law enforcement officials act in the reasonable belief that a search and seizure was consistent with the Fourth Amendment — a position I set forth in Stone v. Powell, 428 U. S. 465, 537-539 (1976). In this case, it was fully reasonable for the Bloomingdale, Ill., police to believe that their search of respondents’ house and automobile comported with the Fourth Amendment as the search was conducted pursuant to a judicially issued warrant. The *247exclusion of probative evidence where the constable has not blundered not only sets the criminal free but also fails to serve any constitutional interest in securing compliance with the important requirements of the Fourth Amendment. On this basis, I concur in the Court’s judgment that the decision of the Illinois Supreme Court must be reversed.
h — 1
The Court declines to address the exclusionary rule question because the Illinois courts were not invited to modify the rule in the first instance. The Court’s refusal to face this important question cannot be ascribed to jurisdictional limitations. I fully agree that the statute which gives us jurisdiction in this cause, 28 U. S. C. § 1257(3), prevents us from deciding federal constitutional claims raised here for the first time on review of state-court decisions. Cardinale v. Louisiana, 394 U. S. 437, 438-439 (1969). But it is equally well established that “ ‘[n]o particular form of words or phrases is essential, but only that the claim of invalidity and the ground therefor be brought to the attention of the state court with fair precision and in due time.’” Street v. New York, 394 U. S. 576, 584 (1969) (quoting New York ex rel. Bryant v. Zimmerman, 278 U. S. 63, 67 (1928)). Notwithstanding the select and controversial instances in which the Court has reversed a state-court decision for “plain error,”1 we have consistently dismissed for want of jurisdiction where the federal claim asserted in this Court was not raised below. But this obviously is not such a case. As the Court points out, “[i]t is clear in this case that respondents expressly raised, at every level of the Illinois judicial system, the claim that the Fourth Amendment had been violated by the actions of the Illinois *248police and that the evidence seized by the officers should be excluded from their trial.” Ante, at 220. Until today, we have not required more.
We have never suggested that the jurisdictional stipulations of § 1257 require that all arguments on behalf of, let alone in opposition to, a federal claim be raised and decided below.2 See R. Stern & E. Gressman, Supreme Court Practice 230 (5th ed. 1978). Dewey v. Des Moines, 173 U. S. 193 (1899), distinguished the raising of constitutional claims and the making of arguments in support of or in opposition to those claims.
“If the question were only an enlargement of the one mentioned in the assignment of errors, or if it were so connected with it in substance as to form but another ground or reason for alleging the invalidity of the personal judgment, we should have no hesitation in holding the assignment sufficient to permit the question to be now raised and argued.
“Parties are not confined here to the same arguments which were advanced in the courts below upon a Federal question there discussed.” Id., at 197-198 (emphasis added).3
*249Under Dewey, which the Court hails as the “fullest treatment of the subject,” ante, at 219, the exclusionary rule issue is but another argument pertaining to the Fourth Amendment question squarely presented in the Illinois courts.
The presentation and decision of respondents’ Fourth Amendment claim fully embraces the argument that due to the nature of the alleged Fourth Amendment violation, the seized evidence should not be excluded. Our decisions concerning the scope of the exclusionary rule cannot be divorced from the Fourth Amendment; they rest on the relationship of Fourth Amendment interests to the objectives of the criminal justice system. See, e. g., United States v. Ceccolini, 435 U. S. 268 (1978); Stone v. Powell, 428 U. S. 465 (1976).4 Similarly, the issues surrounding a proposed good-faith modification are intricately and inseverably tied to the nature of the Fourth Amendment violation: the degree of probable cause, the presence of a warrant, and the clarity of previously announced Fourth Amendment principles all inform the *250good-faith issue. The Court’s own holding that the duty of a reviewing court is simply to ensure that the magistrate had a “substantial basis” for concluding that probable cause existed, ante, at 244-245, is itself but a variation on the good-faith theme. See Brief for Petitioner on Reargument 4-26.
As a jurisdictional requirement, I have no doubt that the exclusionary rule question is before us as an indivisible element of the claim that the Constitution requires exclusion of certain evidence seized in violation of the Fourth Amendment. As a prudential matter, I am unmoved by the Court’s lengthy discourse as to why it must avoid the question. First, the Court turns on its head the axiom that “‘due regard for the appropriate relationship of this Court to state courts,’McGoldrick v. Compagnie Generale Transatlantique, 309 U. S., at 434-435, demands that those courts be given an opportunity to consider the constitutionality of the actions of state officials,” ante, at 221. This statement, written to explain why a state statute should not be struck down on federal grounds not raised in the state courts,5 hardly applies when the question is whether a rule of federal law articulated by this Court should now be narrowed to reduce the scope of federal intrusion into the State’s administration of criminal justice. Insofar as modifications of the federal exclusionary *251rule are concerned, the Illinois courts are bound by this Court’s pronouncements. Cf. Oregon v. Hass, 420 U. S. 714, 719 (1975). I see little point in requiring a litigant to request a state court to overrule or modify one of this Court’s precedents. Far from encouraging the stability of our precedents, the Court’s proposed practice could well undercut stare decisis. Either the presentation of such issues to the lower courts will be a completely futile gesture or the lower courts are now invited to depart from this Court’s decisions whenever they conclude such a modification is in order.6
The Court correctly notes that Illinois may choose to pursue a different course with respect to the state exclusionary rule. If this Court were to formulate a “good-faith” exception to the federal exclusionary rule, the Illinois Supreme Court would be free to consider on remand whether the state exclusionary rule should be modified accordingly. The possibility that it might have relied upon the state exclusionary rule had the “good-faith” question been posed does not constitute independent and adequate state grounds. “The possibility that the state court might have reached the same conclusion if it had decided the question purely as a matter of state law does not create an adequate and independent state ground that relieves this Court of the necessity of considering the federal question.” United Air Lines, Inc. v. Mahin, 410 U. S. 623, 630-631 (1973); Beecher v. Alabama, 389 U. S. 35, 37, n. 3 (1967); C. Wright, The Law of Federal Courts § 107, pp. 747-748 (4th ed. 1983). Nor does having the state court first decide whether the federal exclusionary rule should be modified — and presentation of the federal question does not insure that the equivalent state-law issue will be *252raised or decided7 — avoid the unnecessary decision of a federal question. The Court still must reach a federal question to decide the instant case. Thus, in today’s opinion, the Court eschews modification of the exclusionary rule in favor of interring the test established by Aguilar v. Texas, 378 U. S. 108 (1964), and Spinelli v. United States, 393 U. S. 410 (1969). Nor is the exclusionary rule question avoided — it is simply deferred until “another day.”
It also appears that the Court, in disposing of the case, does not strictly follow its own prudential advice. The Illinois Supreme Court found not only a violation of the Fourth Amendment but also of Article I, § 6, of the Illinois Constitution, which also provides assurance against unreasonable searches and seizures. Taking the Court’s new prudential standards on their own terms, the Illinois courts should be given the opportunity to consider in the first instance whether a “totality of the circumstances” test should replace the more precise rules of Aguilar and Spinelli. The Illinois Supreme Court may decide to retain the established test for purposes of the State Constitution just as easily as it could decide to retain an unmodified exclusionary rule.8
Finally, the Court correctly notes that a fully developed record is helpful if not indispensable for the decision of many issues. I too resist the decision of a constitutional question *253when such guidance is necessary, but the question of whether the exclusionary rule should be modified is an issue of law which obviously goes far beyond and depends little on the subjective good faith of the police officers that searched the Gateses’ property. Moreover, the case comes here with a fully developed record as to the actions of the Bloomingdale, Ill., police. If further factual development of whether the officers in this case acted in good faith were important, that issue should logically be considered on remand, following this Court’s statement of the proper legal standards.9
The Court’s straining to avoid coming to grips with the exclusionary rule issue today may be hard for the country to understand — particularly given earlier statements by some Members of the Court.10 The question has been fully briefed and argued by the parties and amici curiae, including the United States.11 The issue is central to the enforcement of law and the administration of justice throughout the Nation. The Court of Appeals for the second largest Federal Circuit *254has already adopted such an exception, United States v. Williams, 622 F. 2d 880 (CA5 1980) (en banc), cert. denied, 449 U. S. 1127 (1981), and the new Eleventh Circuit is presumably bound by its decision. Several Members of this Court have for some time expressed the need to consider modifying the exclusionary rule, ante, at 224, and Congress as well has been active in exploring the question. See The Exclusionary Rule Bills, Hearings on S. 101, S. 751, and S. 1995 before the Subcommittee on Criminal Law of the Senate Committee on the Judiciary, 97th Cong., 1st and 2d Sess. (1981-1982). At least one State has already enacted a good-faith exception. Colo. Rev. Stat. § 16-3-308 (Supp. 1982). Of course, if there is a jurisdictional barrier to deciding the issue, none of these considerations are relevant. But if no such procedural obstacle exists, I see it as our responsibility to end the uncertainty and decide whether the rule will be modified. The question of whether probable cause existed for the issuance of a warrant and whether the evidence seized must be excluded in this case should follow our reconsideration of the framework by which such issues, as they arise from the Fourth Amendment, are to be handled.
H

>

The exclusionary rule is a remedy adopted by this Court to effectuate the Fourth Amendment right of citizens “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . Although early opinions suggested that the Constitution required exclusion of all illegally obtained evidence, the exclusionary rule “has never been interpreted to proscribe the introduction of illegally seized evidence in all proceedings or against all persons.” Stone v. Powell, 428 U. S., at 486. Because of the inherent trustworthiness of seized tangible evidence and the resulting social costs from its loss through suppression, appli*255cation of the exclusionary rule has been carefully “restricted to those areas where its remedial objectives are thought most efficaciously served.” United States v. Calandra, 414 U. S. 338, 348 (1974). Even at criminal trials the exclusionary rule has not been applied indiscriminately to ban all illegally obtained evidence without regard to the costs and benefits of doing so. Infra, at 256-257. These developments, born of years of experience with the exclusionary rule in operation, forcefully suggest that the exclusionary rule be more generally modified to permit the introduction of evidence obtained in the reasonable good-faith belief that a search or seizure was in accord with the Fourth Amendment.
This evolvement in the understanding of the proper scope of the exclusionary rule embraces several lines of cases. First, standing to invoke the exclusionary rule has been limited to situations where the government seeks to use such evidence against the victim of the unlawful search. Brown v. United States, 411 U. S. 223 (1973); Alderman v. United States, 394 U. S. 165 (1969); Wong Sun v. United States, 371 U. S. 471, 491-492 (1963); Rakas v. Illinois, 439 U. S. 128 (1978).
Second, the rule has not been applied in proceedings other than the trial itself. In United States v. Calandra, supra, the Court refused to extend the rule to grand jury proceedings. “Any incremental deterrent effect which might be achieved by extending the rule to grand jury proceedings is uncertain at best. . . . We therefore decline to embrace a view that would achieve a speculative and undoubtedly minimal advance in the deterrence of police misconduct at the expense of substantially impeding the role of the grand jury.” 414 U. S., at 351-352. Similarly, in United States v. Janis, 428 U. S. 433 (1976), the exclusionary rule was not extended to forbid the use in federal civil proceedings of evidence illegally seized by state officials, since the likelihood of deterring unlawful police conduct was not sufficient to outweigh the social costs imposed by the exclusion.
*256Third, even at a criminal trial, the same analysis has led us to conclude that the costs of excluding probative evidence outweighed the deterrence benefits in several circumstances. We have refused to prohibit the use of illegally seized evidence for the purpose of impeaching a defendant who testifies in his own behalf. United States v. Havens, 446 U. S. 620 (1980); Walder v. United States, 347 U. S. 62 (1954). We have also declined to adopt a “per se or ‘but for’ rule” that would make inadmissible any evidence which comes to light through a chain of causation that began with an illegal arrest. Brown v. Illinois, 422 U. S. 590, 603 (1975). And we have held that testimony of a live witness may be admitted, notwithstanding that the testimony was derived from a con-cededly unconstitutional search. United States v. Ceccolini, 435 U. S. 268 (1978). Nor is exclusion required when law enforcement agents act in good-faith reliance upon a statute or ordinance that is subsequently held to be unconstitutional. United States v. Peltier, 422 U. S. 531 (1975); Michigan v. DeFillippo, 443 U. S. 31 (1979).12 Cf. United States v. Caceres, 440 U. S. 741, 754-757 (1979) (exclusion not *257required of evidence tainted by violation of an executive department’s rules concerning electronic eavesdropping).
A similar balancing approach is employed in our decisions limiting the scope of the exclusionary remedy for Fifth Amendment violations, Oregon v. Hass, 420 U. S. 714 (1975); Harris v. New York, 401 U. S. 222 (1971); Michigan v. Tucker, 417 U. S. 433 (1974), and our cases considering whether Fourth Amendment decisions should be applied retroactively, United States v. Peltier, supra, at 538-539; Williams v. United States, 401 U. S. 646, 654-655 (1971) (plurality opinion); Desist v. United States, 394 U. S. 244, 249-250 (1969); Linkletter v. Walker, 381 U. S. 618, 636-639 (1965). But see United States v. Johnson, 457 U. S. 537 (1982).
These cases reflect that the exclusion of evidence is not a personal constitutional right but a remedy, which, like all remedies, must be sensitive to the costs and benefits of its imposition. The trend and direction of our exclusionary rule decisions indicate not a lesser concern with safeguarding the Fourth Amendment but a fuller appreciation of the high costs incurred when probative, reliable evidence is barred because of investigative error. The primary cost, of course, is that the exclusionary rule interferes with the truthseeking function of a criminal trial by barring relevant and trustworthy evidence.13 We will never know how many guilty defendants go free as a result of the rule’s operation. But any rule of evidence that denies the jury access to clearly probative and reliable evidence must bear a heavy burden of justification, *258and must be carefully limited to the circumstances in which it will pay its way by deterring official lawlessness. I do not presume that modification of the exclusionary rule will, by itself, significantly reduce the crime rate — but that is no excuse for indiscriminate application of the rule.
The suppression doctrine entails other costs as well. It would be surprising if the suppression of evidence garnered in good faith, but by means later found to violate the Fourth Amendment, did not deter legitimate as well as unlawful police activities. To the extent the rule operates to discourage police from reasonable and proper investigative actions, it hinders the solution and even the prevention of crime. A tremendous burden is also placed on the state and federal judicial systems. One study reveals that one-third of federal defendants going to trial file Fourth Amendment suppression motions, and 70% to 90% of these involve formal hearings. General Accounting Office, Comptroller General of the United States, Impact of the Exclusionary Rule on Federal Criminal Prosecutions 10 (1979).
The rule also exacts a heavy price in undermining public confidence in the reasonableness of the standards that govern the criminal justice system. “[Although the [exclusionary] rule is thought to deter unlawful police activity in part through the nurturing of respect for Fourth Amendment values, if applied indiscriminately it may well have the opposite effect of generating disrespect for the law and the administration of justice.” Stone v. Powell, 428 U. S., at 490-491. As Justice Powell observed in Stone v. Powell, supra, at 490: “The disparity in particular cases between the error committed by the police officer and the windfall afforded a guilty defendant by application of the rule is contrary to the idea of proportionality that is essential to the concept of justice.”
For these reasons, “application of the [exclusionary] rule has been restricted to those areas where its remedial objectives are thought most efficaciously served.” United States *259v. Calandra, 414 U. S., at 348.14 The reasoning of our recent cases strongly suggests that there is insufficient justification to suppress evidence at a criminal trial which was seized in the reasonable belief that the Fourth Amendment was not violated. The deterrent effect of the exclusionary rule has never been established by empirical evidence, de*260spite repeated attempts. United States v. Janis, 428 U. S., at 449-453; Irvine v. California, 347 U. S. 128, 136 (1954). But accepting that the rule deters some police misconduct, it is apparent as a matter of logic that there is little if any deterrence when the rule is invoked to suppress evidence obtained by a police officer acting in the reasonable belief that his conduct did not violate the Fourth Amendment. As we initially observed in Michigan v. Tucker, 417 U. S., at 447, and reiterated in United States v. Peltier, 422 U. S., at 539:
“ ‘The deterrent purpose of the exclusionary rule necessarily assumes that the police have engaged in willful, or at the very least negligent, conduct which has deprived the defendant of some right. By refusing to admit evidence gained as a result of such conduct, the courts hope to instill in those particular investigating officers, or in their future counterparts, a greater degree of care toward the rights of an accused. Where the official action was pursued in complete good faith, however, the deterrence rationale loses much of its force.’”
The Court in Peltier continued, id., at 542:
“If the purpose of the exclusionary rule is to deter unlawful police conduct then evidence obtained from a search should be suppressed only if it can be said that the law enforcement officer had knowledge, or may properly be charged with knowledge, that the search was unconstitutional under the Fourth Amendment.”
See also United States v. Janis, supra, at 459, n. 35 (“[T]he officers here were clearly acting in good faith ... a factor that the Court has recognized reduces significantly the potential deterrent effect of exclusion”). The deterrent value of the exclusionary sanction is most effective when officers engage in searches and seizures under circumstances “so lacking in indicia of probable cause as to render official belief in its existence entirely unreasonable.” Brown v. Illinois, 422 U. S., at 610-611 (Powell, J., concurring in part). On the *261other hand, when officers perform their tasks in the good-faith belief that their action comported with constitutional requirements, the deterrent function of the exclusionary rule is so minimal, if not nonexistent, that the balance clearly favors the rule’s modification.15
*262B
There are several types of Fourth Amendment violations that may be said to fall under the rubric of “good faith.” “[TJhere will be those occasions where the trial or appellate court will disagree on the issue of probable cause, no matter how reasonable the grounds for arrest appeared to the officer and though reasonable men could easily differ on the question. It also happens that after the events at issue have occurred, the law may change, dramatically or ever so slightly, but in any event sufficiently to require the trial judge to hold that there was not probable cause to make the arrest and to seize the evidence offered by the prosecution. ...” Stone v. Powell, 428 U. S., at 539-540 (White, J., dissenting). The argument for a good-faith exception is strongest, however, when law enforcement officers have reasonably relied on a judicially issued search warrant.
This Court has never set forth a rationale for applying the exclusionary rule to suppress evidence obtained pursuant to a search warrant; it has simply done so without considering whether Fourth Amendment interests will be advanced. It is my view that they generally will not be. When officers have dutifully obtained a search warrant from a judge or magistrate, and execute the warrant as directed by its terms, .exclusion of the evidence thus obtained cannot be expected to deter future reliance on such warrants. The warrant is prima facie proof that the officers acted reasonably in conducting the search or seizure; “[o]nce the warrant issues, there is literally nothing more that the policeman can do in seeking to comply with the law.” Stone v. Powell, supra, at 498 (Burger, C. J., concurring).16 As Justice Stevens *263put it in writing for the Court in United States v. Ross, 456 U. S. 798, 823, n. 32 (1982): “[A] warrant issued by a magistrate normally suffices to establish” that a law enforcement officer has “acted in good faith in conducting the search.” Nevertheless, the warrant may be invalidated because of a technical defect or because, as in this case, the judge issued a warrant on information later determined to fall short of probable cause. Excluding evidence for these reasons can have no possible deterrent effect on future police conduct, unless it is to make officers less willing to do their duty. Indeed, applying the exclusionary rule to warrant searches may well reduce incentives for police to utilize the preferred warrant procedure when a warrantless search may be permissible under one of the established exceptions to the warrant requirement. See ante, at 236; Brown v. Illinois, 422 U. S., at 611, and n. 3 (Powell, J., concurring in part); P. Johnson, New Approaches to Enforcing the Fourth Amendment 11 (unpublished paper, 1978). See also United States v. United States District Court, 407 U. S. 297, 316-317 (1972); United States v. Ventresca, 380 U. S. 102, 106-107 (1965).
Opponents of the proposed “reasonable belief” exception suggest that such a modification would allow magistrates and judges to flout the probable-cause requirements in issuing warrants. This is a novel concept: the exclusionary rule was adopted to deter unlawful searches by police, not to punish the errors of magistrates and judges. Magistrates must be neutral and detached from law enforcement operations and I would not presume that a modification of the exclusionary rule will lead magistrates to abdicate their responsibility to apply the law.17 In any event, I would apply the exclusion*264ary rule when it is plainly evident that a magistrate or judge had no business issuing a warrant. See, e. g., Aguilar v. Texas, 378 U. S. 108 (1964); Nathanson v. United States, 290 U. S. 41 (1933). Similarly, the good-faith exception would not apply if the material presented to the magistrate or judge is false or misleading, Franks v. Delaware, 438 U. S. 154 (1978), or so clearly lacking in probable cause that no well-trained officer could reasonably have thought that a warrant should issue.
Another objection is that a reasonable-belief exception will encompass all searches and seizures on the frontier of the Fourth Amendment and that such cases will escape review on the question of whether the officer’s action was permissible, denying needed guidance from the courts and freezing Fourth Amendment law in its present state. These fears are unjustified. The premise of the argument is that a court must first decide the reasonable-belief issue before turning to the question of whether a Fourth Amendment violation has occurred. I see no need for such an inflexible practice. When a Fourth Amendment case presents a novel question of law whose resolution is necessary to guide future action by law enforcement officers and magistrates, there is sufficient reason for the Court to decide the violation issue before turning to the good-faith question. Indeed, it may be difficult to *265determine whether the officers acted reasonably until the Fourth Amendment issue is resolved.18 In other circumstances, however, a suppression motion poses no Fourth Amendment question of broad import — the issue is simply whether the facts in a given case amounted to probable cause — in these cases, it would be prudent for a reviewing court to immediately turn to the question of whether the officers acted in good faith. Upon finding that they had, there would generally be no need to consider the probable-cause question. I doubt that our Fourth Amendment jurisprudence would suffer thereby. It is not entirely clear to me that the law in this area has benefited from the constant pressure of fully litigated suppression motions. The result usually has been that initially bright-line rules have disappeared in a sea of ever-finer distinctions. Moreover, there is much to be said for having Fourth Amendment jurispru*266dence evolve in part, albeit perhaps at a slower pace, in other settings.19
Finally, it is contended that a good-faith exception will be difficult to apply in practice. This concern appears grounded in the assumption that courts would inquire into the subjective belief of the law enforcement officers involved. I would eschew such investigations. “[Sjending state and federal courts on an expedition into the minds of police officers would produce a grave and fruitless misallocation of judicial resources.” Massachusetts v. Painten, 389 U. S. 560, 565 (1968) (White, J., dissenting). Moreover, “[sjubjective intent alone . . . does not make otherwise lawful conduct illegal or unconstitutional.” Scott v. United States, 436 U. S. 128, 136 (1978). Just last Term, we modified the qualified immunity public officials enjoy in suits seeking damages against federal officials for alleged deprivations of constitutional rights, eliminating the subjective component of the standard. See Harlow v. Fitzgerald, 457 U. S. 800 (1982). Although *267searches pursuant to a warrant will rarely require any deep inquiry into reasonableness, I would measure the reasonableness of a particular search or seizure only by objective standards. Even for warrantless searches, the requirement should be no more difficult to apply than the closely related good-faith test which governs civil suits under 42 U. S. C. § 1983. In addition, the burden will likely be offset by the reduction in the number of cases which will require elongated considerations of the probable-cause question, and will be greatly outweighed by the advantages in limiting the bite of the exclusionary rule to the field in which it is most likely to have its intended effects.
hH h — I HH
Since a majority of the Court deems it inappropriate to address the good-faith issue, I briefly address the question that the Court does reach — whether the warrant authorizing the search and seizure of respondents’ car and home was constitutionally valid. Abandoning the “two-pronged test” of Aguilar v. Texas, 378 U. S. 108 (1964), and Spinelli v. United States, 393 U. S. 410 (1969), the Court upholds the validity of the warrant under a new “totality of the circumstances” approach. Although I agree that the warrant should be upheld, I reach this conclusion in accordance with the Aguilar-Spinelli framework.
A
For present purposes, the Aguilar-Spinelli rules can be summed up as follows. First, an affidavit based on an informant’s tip, standing alone, cannot provide probable cause for issuance of a warrant unless the tip includes information that apprises the magistrate of the informant’s basis for concluding that the contraband is where he claims it is (the “basis of knowledge” prong), and the affiant informs the magistrate of his basis for believing that the informant is credible (the “veracity” prong). Aguilar, supra, at 114; *268Spinelli, supra, at 412-413,416.20 Second, if a tip fails under either or both of the two prongs, probable cause may yet be established by independent police investigatory work that corroborates the tip to such an extent that it supports “both the inference that the informer was generally trustworthy and that he made his charge ... on the basis of information obtained in a reliable way.” Spinelli, supra, at 417. In instances where the officers rely on corroboration, the ultimate question is whether the corroborated tip “is as trustworthy as a tip which would pass Aguilar's tests without independent corroboration.” 393 U. S., at 415.
In the present case, it is undisputed that the anonymous tip, by itself, did not furnish probable cause. The question is whether those portions of the affidavit describing the results of the police investigation of the respondents, when considered in light of the tip, “would permit the suspicions engendered by the informant’s report to ripen into a judgment that a crime was probably being committed.” Spinelli, supra, at 418. The Illinois Supreme Court concluded that the corroboration was insufficient to permit such a ripening. 85 Ill. 2d 376, 387, 423 N. E. 2d 887, 892 (1981). The court reasoned as follows:
“[T]he nature of the corroborating evidence in this case would satisfy neither the ‘basis of knowledge’ nor the *269‘veracity’ prong of Aguilar. Looking to the affidavit submitted as support for Detective Mader’s request that a search warrant issue, we note that the corroborative evidence here was only of clearly innocent activity. Mader’s independent investigation revealed only that Lance and Sue Gates lived on Greenway Drive; that Lance Gates booked passage on a flight to Florida; that upon arriving he entered a room registered to his wife; and that he and his wife left the hotel together by car. The corroboration of innocent activity is insufficient to support a finding of probable cause.” Id., at 390, 423 N. E. 2d, at 893.
In my view, the lower court’s characterization of the Gateses’ activity here as totally “innocent” is dubious. In fact, the behavior was quite suspicious. I agree with the Court, ante, at 243, that Lance Gates’ flight to West Palm Beach, an area known to be a source of narcotics, the brief overnight stay in a motel, and apparent immediate return north, suggest a pattern that trained law enforcement officers have recognized as indicative of illicit drug-dealing activity.21
Even, however, had the corroboration related only to completely innocuous activities, this fact alone would not preclude the issuance of a valid warrant. The critical issue is not whether the activities observed by the police are innocent or suspicious. Instead, the proper focus should be on whether the actions of the suspects, whatever their nature, give rise to an inference that the informant is credible and that he obtained his information in a reliable manner.
Thus, in Draper v. United States, 358 U. S. 307 (1959), an informant stated on September 7 that Draper would be carrying narcotics when he arrived by train in Denver on the morning of September 8 or September 9. The informant also provided the police with a detailed physical description *270of the clothes Draper would be wearing when he alighted from the train. The police observed Draper leaving a train on the morning of September 9, and he was wearing the precise clothing described by the informant. The Court held that the police had probable cause to arrest Draper at this point, even though the police had seen nothing more than the totally innocent act of a man getting off a train carrying a briefcase. As we later explained in Spinelli, the important point was that the corroboration showed both that the informant was credible, i. e., that he “had not been fabricating his report out of whole cloth,” Spinelli, 393 U. S., at 417, and that he had an adequate basis of knowledge for his allegations, “since the report was of the sort which in common experience may be recognized as having been obtained in a reliable way.” Id., at 417-418. The fact that the informant was able to predict, two days in advance, the exact clothing Draper would be wearing dispelled the possibility that his tip was just based on rumor or “an offhand remark heard at a neighborhood bar.” Id., at 417. Probably Draper had planned in advance to wear these specific clothes so that an accomplice could identify him. A clear inference could therefore be drawn that the informant was either involved in the criminal scheme himself or that he otherwise had access to rehable, inside information.22
*271As in Draper, the police investigation in the present case satisfactorily demonstrated that the informant’s tip was as trustworthy as one that would alone satisfy the Aguilar tests. The tip predicted that Sue Gates would drive to Florida, that Lance Gates would fly there a few days after May 3, and that Lance would then drive the car back. After the police corroborated these facts,23 the judge could reasonably have inferred, as he apparently did, that the informant, who had specific knowledge of these unusual travel plans, did not make up his story and that he obtained his information in a reliable way. It is theoretically possible, as respondents insist, that the tip could have been supplied by a “vindictive travel agent” and that the Gateses’ activities, although unusual, might not have been unlawful.24 But Aguilar and Spinelli, like our other cases, do not require that certain guilt be established before a warrant may properly be issued. “[OJnly the probability, and not a prima facie show*272ing, of criminal activity is the standard of probable cause.” Spinelli, supra, at 419 (citing Beck v. Ohio, 379 U. S. 89, 96 (1964)). I therefore conclude that the judgment of the Illinois Supreme Court invalidating the warrant must be reversed.
B
The Court agrees that the warrant was valid, but, in the process of reaching this conclusion, it overrules the Aguilar-Spinelli tests and replaces them with a “totality of the circumstances” standard. As shown above, it is not at all necessary to overrule Aguilar-Spinelli in order to reverse the judgment below. Therefore, because I am inclined to believe that, when applied properly, the Aguilar-Spinelli rules play an appropriate role in probable-cause determinations, and because the Court’s holding may foretell an evisceration of the probable-cause standard, I do not join the Court’s holding.
The Court reasons, ante, at 233, that the “veracity” and “basis of knowledge” tests are not independent, and that a deficiency as to one can be compensated for by a strong showing as to the other. Thus, a finding of probable cause may be based on a tip from an informant “known for the unusual reliability of his predictions” or from “an unquestionably honest citizen,” even if the report fails thoroughly to set forth the basis upon which the information was obtained. Ibid. If this is so, then it must follow a fortiori that “the affidavit of an officer, known by the magistrate to be honest and experienced, stating that [contraband] is located in a certain building” must be acceptable. Spinelli, 393 U. S., at 424 (White, J., concurring). It would be “quixotic” if a similar statement from an honest informant, but not one from an honest officer, could furnish probable cause. Ibid. But we have repeatedly held that the unsupported assertion or belief of an officer does not satisfy the probable-cause requirement. See, e. g., Whiteley v. Warden, 401 U. S. 560, 564-565 *273(1971); Jones v. United States, 362 U. S. 257, 269 (1960); Nathanson v. United States, 290 U. S. 41 (1933).25 Thus, this portion of today’s holding can be read as implicitly rejecting the teachings of these prior holdings.
The Court may not intend so drastic a result. Indeed, the Court expressly reaffirms, ante, at 239, the validity of cases such as Nathanson that have held that, no matter how reliable the affiant-officer may be, a warrant should not be issued unless the affidavit discloses supporting facts and circumstances. The Court limits these cases to situations involving affidavits containing only “bare conclusions” and holds that, if an affidavit contains anything more, it should be left to the issuing magistrate to decide, based solely on “practicality]” and “common sense,” whether there is a fair probability that contraband will be found in a particular place. Ante, at 238-239.
Thus, as I read the majority opinion, it appears that the question whether the probable-cause standard is to be diluted is left to the common-sense judgments of issuing magistrates. I am reluctant to approve any standard that does not expressly require, as a prerequisite to issuance of a warrant, some showing of facts from which an inference may be drawn that the informant is credible and that his information was obtained in a reliable way. The Court is correctly concerned with the fact that some lower courts have been applying Aguilar-Spinelli in an unduly rigid manner.26 I believe, however, that with clarification of the rule of corroborating *274information, the lower courts are fully able to properly interpret Aguilar-Spinelli and avoid such unduly rigid applications. I may be wrong; it ultimately may prove to be the case that the only profitable instruction we can provide to magistrates is to rely on common sense. But the question whether a particular anonymous tip provides the basis for issuance of a warrant will often be a difficult one, and I would at least attempt to provide more precise guidance by clarifying Aguilar-Spinelli and the relationship of those cases with Draper before totally abdicating our responsibility in this area. Hence, I do not join the Court’s opinion rejecting the Aguilar-Spinelli rules.

 See, e. g., Eddings v. Oklahoma, 455 U. S. 104 (1982); Wood v. Georgia, 450 U. S. 261 (1981); Vachon v. New Hampshire, 414 U. S. 478 (1974) (per curiam). Of course, to the extent these cases were correctly decided, they indicate a fortiori that the exclusionary rule issue in this case is properly before us.

 The Court has previously relied on issues and arguments not raised in the state court below in order to dispose of a federal question that was properly raised. In Stanley v. Illinois, 406 U. S. 645, 658 (1972), the Court held that unmarried fathers could not be denied a hearing on parental fitness that was afforded other Illinois parents. Although this issue was not presented in the Illinois courts, the Court found that it could properly be considered: “we dispose of the case on the constitutional premise raised below, reaching the result by a method of analysis readily available to the state court. For the same reason the strictures of Cardinale v. Louisiana, 394 U. S. 437 (1969), and Hill v. California, 401 U. S. 797 (1971), have been fully observed.” Id., at 658, n. 10. The dissent argued that the Court was deciding a due process claim instead of an equal protection one, but there was no suggestion that it mattered at all that the Court had relied on a different type of equal protection argument.

 As the Court explains, ante, at 220, n. 2, in Dewey, the plaintiff in error argued only that the imposition of personal liability against him violated *249the Due Process Clause of the Fourteenth Amendment, because he had not received personal notice of the assessment proceedings. In this Court, the plaintiff in error sought to raise a takings argument for the first time. The Court declined to pass on the issue because, although arising from a single factual occurrence, the two claims “are not in anywise necessarily connected.” 173 U. S., at 198.

 The Court relies on these cases for the surprising assertion that the Fourth Amendment and exclusionary rule questions are “distinct.” I had understood the very essence of Rakas v. Illinois, 439 U. S. 128 (1978), to be that standing to seek exclusion of evidence could not be divorced from substantive Fourth Amendment rights. Past decisions finding that the remedy of exclusion is not always appropriate upon the finding of a Fourth Amendment violation acknowledge the close relationship of the issues. For example, in United States v. Ceccolini it was said: “The constitutional question under the Fourth Amendment was phrased in Wong Sun v. United States, 371 U. S. 471 (1963), as whether ‘the connection between the lawless conduct of the police and the discovery of the challenged evidence has “become so attenuated as to dissipate the taint.” ’ ” 435 U. S., at 273-274. It is also suprising to learn that the issues in Stone v. Powell are “distinct” from the Fourth Amendment.

 Consider the full context of the statement in McGoldrick v. Compagnie Generale Transatlantique, 309 U. S. 430, 434 (1940):
“In cases coming here from state courts in which a state statute is assailed as unconstitutional, there are reasons of peculiar force which should lead us to refrain from deciding questions not presented or decided in the highest court of the state whose judicial action we are called upon to review. Apart from the reluctance with which every court should proceed to set aside legislation as unconstitutional on grounds not properly presented, due regard for the appropriate relationship of this Court to state courts requires us to decline to consider and decide questions affecting the validity of state statutes not urged or considered there. It is for these reasons that this Court, where the constitutionality of a statute has been upheld in the state court, consistently refuses to consider any grounds of attack not raised or decided in that court.”

 The Court observes that “although the Illinois courts applied the federal exclusionary rule, there was never ‘any real contest’ upon the point.” Ante, at 223. But the proper forum for a “real contest” on the continued vitality of the exclusionary rule that has developed from our decisions in Weeks v. United States, 232 U. S. 383 (1914), and Mapp v. Ohio, 367 U. S. 643 (1961), is this Court.

 Nor is there any reason for the Illinois courts to decide that question in advance of this Court’s decision on the federal exclusionary rule. Until the federal rule is modified, the state-law question is entirely academic. The state courts should not be expected to render such purely advisory decisions.

 Respondents press this very argument. Brief for Respondents 24-27; Brief for Respondents on Reargument 6. Of course, under traditional principles the possibility that the state court might reach a different conclusion in interpreting the State Constitution does not make it improper for us to decide the federal issue. Delaware v. Prouse, 440 U. S. 648, 651-653 (1979); Zacchini v. Scripps-Howard Broadcasting Co., 433 U. S. 562, 568 (1977).

 It also should be noted that the requirement that the good-faith issue be presented to the Illinois courts has little to do with whether the record is complete. I doubt that the raising of the good-faith issue below would have been accompanied by any different record. And this Court may dismiss a writ of certiorari as improvidently granted when the record makes decision of a federal question unwise. See, e. g., Minnick v. California Dept. of Corrections, 452 U. S. 105 (1981).

 In California v. Minjares, 443 U. S. 916, 928 (1979) (REHNQUIST, J., joined by Burger, C. J., dissenting from the denial of stay), the author of today’s opinion for the Court urged that the parties be directed to brief whether the exclusionary rule should be retained. In Minjares, like this case, respondents had raised a Fourth Amendment claim but petitioners had not attacked the validity of the exclusionary rule in the state court. See also Robbins v. California, 453 U. S. 420, 437 (1981) (REHNQUIST, J., dissenting) (advocating overruling of Mapp v. Ohio, supra).

 Ironically, in Mapp v. Ohio, supra, petitioners did not ask the Court to partially overrule Wolf v. Colorado, 338 U. S. 25 (1949). The sole argument to apply the exclusionary rule to the States is found in a single paragraph in an amicus brief filed by the American Civil Liberties Union.

 To be sure, Peltier and DeFillippo did not modify the exclusionary rule itself. Peltier held that Almeida-Sanchez v. United States, 413 U. S. 266 (1973), was not to be given retroactive effect; DeFillippo upheld the validity of an arrest made in good-faith reliance on an ordinance subsequently declared unconstitutional. The effect of these decisions, of course, was that evidence was not excluded because of the officer’s reasonable belief that he was acting lawfully, and the Court’s reasoning, as I discuss infra, at 260-261, leads inexorably to the more general modification of the exclusionary rule I favor. Indeed, Justice Brennan recognized this in his dissent in Peltier, 422 U. S., at 551-552.
I recognize that we have held that the exclusionary rule required suppression of evidence obtained in searches carried out pursuant to statutes, not previously declared unconstitutional, which purported to authorize the searches in question without probable cause and without a valid warrant. See, e. g., Torres v. Puerto Rico, 442 U. S. 465 (1979); Almeida-Sanchez v. United States, supra; Sibron v. New York, 392 U. S. 40 (1968); Berger v. New York, 388 U. S. 41 (1967). The results in these cases may well be different under a “good-faith” exception to the exclusionary rule.

 The effects of the exclusionary rule are often felt before a case reaches trial. A recent study by the National Institute of Justice of felony arrests in California during the years 1976-1979 “found a major impact of the exclusionary rule on state prosecutions.” National Institute of Justice, The Effects of the Exclusionary Rule: A Study in California 2 (1982). The study found that 4.8% of the more than 4,000 felony cases declined for prosecution were rejected because of search and seizure problems. The exclusionary rule was found to have a particularly pronounced effect in drug cases; prosecutors rejected approximately 30% of all felony drug arrests because of search and seizure problems.

 Our decisions applying the exclusionary rule have referred to the “imperative of judicial integrity,” Elkins v. United States, 364 U. S. 206, 222 (1960), although recent opinions of the Court make clear that the primary function of the exclusionary rule is to deter violations of the Fourth Amendment, Stone v. Powell, 428 U. S., at 486; United States v. Janis, 428 U. S. 433, 446 (1976); United States v. Calandra, 414 U. S., at 348. I do not dismiss the idea that the integrity of the courts may be compromised when illegally seized evidence is admitted, but I am convinced that the force of the argument depends entirely on the type of search or seizure involved. At one extreme, there are lawless invasions of personal privacy that shock the conscience, and the admission of evidence so obtained must be suppressed as a matter of due process, entirely aside from the Fourth Amendment. See, e. g., Rochin v. California, 342 U. S. 165 (1952). Also deserving of exclusionary treatment are searches and seizures perpetrated in intentional and flagrant disregard of Fourth Amendment principles. But the question of exclusion must be viewed through a different lens when a Fourth Amendment violation occurs because the police have reasonably erred in assessing the facts, mistakenly conducted a search authorized under a presumably valid statute, or relied in good faith upon a warrant not supported by probable cause. In these circumstances, the integrity of the courts is not implicated. The violation of the Fourth Amendment is complete before the evidence is admitted. Thus, “[t]he primary meaning of ‘judicial integrity’ in the context of evidentiary rules is that the courts must not commit or encourage violations of the Constitution.” United States v. Janis, supra, at 458, n. 35. Cf. United States v. Peltier, 422 U. S. 531, 537 (1975) (“The teaching of these retroactivity cases is that if the law enforcement officers reasonably believed in good faith that evidence they had seized was admissible at trial, the ‘imperative of judicial integrity’ is not offended by the introduction into evidence of that material even if decisions subsequent to the search or seizure have broadened the exclusionary rule to encompass evidence seized in that manner”). I am content that the interests in judicial integrity run along with rather than counter to the deterrence concept, and that to focus upon the latter is to promote, not denigrate, the former.

 It has been suggested that the deterrence function of the exclusionary rule has been understated by viewing the rule as aimed at special deterrence, when, in fact, the exclusionary rule is directed at “affecting the wider audience of law enforcement officials and society at large.” 1 W. LaFave, Search and Seizure 6 (1983 Supp.). See also Mertens & Wasserstrom, The Good Faith Exception to the Exclusionary Rule: Deregulating the Police and Derailing the Law, 70 Geo. L. J. 365, 399-401 (1981). I agree that the exclusionary rule’s purpose is not only, or even primarily, to deter the individual police officer involved in the instant ease. It appears that this objection assumes that the proposed modification of the exclusionary rule will turn only on the subjective “good faith” of the officer. Grounding the modification in objective reasonableness, however, retains the value of the exclusionary rule as an incentive for the law enforcement profession as a whole to conduct themselves in accord with the Fourth Amendment. Dunaway v. New York, 442 U. S. 200, 221 (1979) (Stevens, J., concurring).
Indeed, the present indiscriminate application of the exclusionary rule may hinder the educative and deterrent function of the suppression remedy. “Instead of disciplining their employees, police departments generally have adopted the attitude that the courts cannot be satisfied, that the rules are hopelessly complicated and subject to change, and that the suppression of evidence is the court’s problem and not the departments’.” Kaplan, The Limits of the Exclusionary Rule, 26 Stan. L. Rev. 1027, 1050 (1974). If evidence is suppressed only when a law enforcement officer 'should have known that he was violating the Fourth Amendment, police departments may look more seriously at the officer’s misconduct when suppression is invoked. Moreover, by providing that evidence gathered in good-faith reliance on a reasonable rule will not be excluded, a good-faith exception creates an incentive for police departments to formulate rules governing activities of officers in the search-and-seizure area. Many commentators, including proponents of the exclusionary sanction, recognize that the formulation of such rules by police departments, and the training necessary to implement these guidelines in practice, are perhaps the most effective means of protecting Fourth Amendment rights. See K. Davis, Discretionary Justice (1969); McGowan, Rule-Making and the Police, 70 Mich. L. Rev. 659 (1972); Amsterdam, Perspectives on the Fourth Amendment, 58 Minn. L. Rev. 349, 416-431 (1974).

 The Attorney General’s Task Force on Violent Crime concluded that the situation in which an officer relies on a duly authorized warrant
“is a particularly compelling example of good faith. A warrant is a judicial mandate to an officer to conduct a search or make an arrest, and the officer has a sworn duty to carry out its provisions. Accordingly, we believe that there should be a rule which states that evidence obtained pursuant to and *263within the scope of a warrant is prima facie the result of good faith on the part of the officer seizing the evidence.” U. S. Dept, of Justice, Attorney General’s Task Force on Violent Crime, Final Report 55 (1981).

 Much is made of Shadwick v. City of Tampa, 407 U. S. 345 (1972), where we held that magistrates need not be legally trained. Shadwick’s holding was quite narrow. First, the Court insisted that “an issuing mag*264istrate must meet two tests. He must be neutral and detached, and he must be capable of determining whether probable cause exists for the requested arrest or search.” Id., at 350. Second, in Shadwick, the Court Clerk’s authority extended only to the relatively straightforward task of issuing arrest warrants for breach of municipal ordinances. To issue search warrants, an individual must be capable of making the probable-cause judgments involved. In this regard, I reject the Court’s insinuation that it is too much to expect that persons who issue warrants remain abreast of judicial refinements of probable cause. Ante, at 235. Finally, as indicated in text, I do not propose that a warrant clearly lacking a basis in probable cause can support a “good-faith” defense to invocation of the exclusionary rule.

 Respondents and some amici contend that this practice would be inconsistent with the Art. Ill requirement of an actual case or controversy. I have no doubt that a defendant who claims that he has been subjected to an unlawful search or seizure and seeks suppression of the evidentiary fruits thereof raises a live controversy within the Art. Ill authority of federal courts to adjudicate. It is fully appropriate for a court to decide whether there has been a wrong before deciding what remedy to impose. When questions of good-faith immunity have arisen under 42 U. S. C. § 1983, we have not been constrained to reach invariably the immunity question before the violation issue. Compare O’Connor v. Donaldson, 422 U. S. 563 (1975) (finding constitutional violation and remanding for consideration of good-faith defense), with Procunier v. Navarette, 434 U. S. 555, 566, n. 14 (1978) (finding good-faith defense first). Similarly, we have exercised discretion at times in deciding the merits of a claim even though the error was harmless, while on other occasions resolving the case solely by reliance on the harmless-error doctrine. Compare Milton v. Wainwright, 407 U. S. 371, 372 (1972) (declining to decide whether admission of confession was constitutional violation because error, if any, was harmless beyond a reasonable doubt), with Coleman v. Alabama, 399 U. S. 1 (1970) (upholding right to counsel at preliminary hearing and remanding for harmless-error determination).

 For example, a pattern or practice of official conduct that is alleged to violate Fourth Amendment rights may be challenged by an aggrieved individual in a suit for declaratory or injunctive relief. See, e. g., Zurcher v. Stanford Daily, 486 U. S. 547 (1978). (Of course, there are limits on the circumstances in which such actions will lie. Rizzo v. Goode, 423 U. S. 362 (1976); Los Angeles v. Lyons, 461 U. S. 95 (1983).) Although a municipality is not liable under 42 U. S. C. § 1983 on a theory of respondeat superior, local governing bodies are subject to suit for constitutional torts resulting from implementation of local ordinances, regulations, policies, or even customary practices. Monell v. New York City Dept. of Social Services, 436 U. S. 658 (1978). Such entities enjoy no immunity defense that might impede resolution of the substantive constitutional issue. Owen v. City of Independence, 445 U. S. 622 (1980). In addition, certain state courts may continue to suppress, as a matter of state law, evidence in state trials for any Fourth Amendment violation. These cases would likely provide a sufficient supply of state criminal cases in which to resolve unsettled questions of Fourth Amendment law. As a final alternative, I would entertain the possibility of according the benefits of a new Fourth Amendment rule to the party in whose case the rule is first announced. See Stovall v. Denno, 388 U. S. 293, 301 (1967).

 The “veracity” prong is satisfied by a recitation in the affidavit that the informant previously supplied accurate information to the police, see McCray v. Illinois, 386 U. S. 300, 303-304 (1967), or by proof that the informant gave his information against his penal interest, see United States v. Harris, 403 U. S. 573, 583-584 (1971) (plurality opinion). The “basis of knowledge” prong is satisfied by a statement from the informant that he personally observed the criminal activity, or, if he came by the information indirectly, by a satisfactory explanation of why his sources were reliable, or, in the absence of a statement detailing the manner in which the information was gathered, by a description of the accused’s criminal activity in sufficient detail that the magistrate may infer that the informant is relying on something more substantial than casual rumor or an individual’s general reputation. Spinelli v. United States, 393 U. S., at 416.

 See United States v. Mendenhall, 446 U. S. 544, 562 (1980) (Powell, J., concurring in part and concurring in judgment).

 Thus, as interpreted in Spinelli, the Court in Draper held that there was probable cause because “the kind of information related by the informant [was] not generally sent ahead of a person’s arrival in a city except to those who are intimately connected with making careful arrangements for meeting him.” Spinelli, supra, at 426 (White, J., concurring). As I said in Spinelli, the conclusion that Draper itself was based on this fact is far from inescapable. Prior to Spinelli, Draper was susceptible to the interpretation that it stood for the proposition that “the existence of the tenth and critical fact is made sufficiently probable to justify the issuance of a warrant by verifying nine other facts coming from the same source.” Spinelli, supra, at 426-427 (White, J., concurring). But it now seems clear that the Court in Spinelli rejected this reading of Draper.
Justice Brennan, post, at 280, n. 3, 281-282, erroneously interprets my Spinelli concurrence as espousing the view that “corroboration of cer*271tain details in a tip may be sufficient to satisfy the veracity, but not the basis of knowledge, prong of Aguilar.” Others have made the same mistake. See, e. g., Comment, 20 Am. Crim. L. Rev. 99, 105 (1982). I did not say that corroboration could never satisfy the “basis of knowledge” prong. My concern was, and still is, that the prong might be deemed satisfied on the basis of corroboration of information that does not in any way suggest that the informant had an adequate basis of knowledge for his report. If, however, as in Draper, the police corroborate information from which it can be inferred that the informant’s tip was grounded on inside information, this corroboration is sufficient to satisfy the “basis of knowledge” prong. Spinelli, 393 U. S., at 426 (White, J., concurring). The rules would indeed be strange if, as Justice Brennan suggests, post, at 284, the “basis of knowledge” prong could be satisfied by detail in the tip alone, but not by independent police work.

 Justice Stevens is correct, post, at 291, that one of the informant’s predictions proved to be inaccurate. However, I agree with the Court, ante, at 245, n. 14, that an informant need not be infallible.

 It is also true, as Justice Stevens points out, post, at 292, n. 3, that the fact that respondents were last seen leaving West Palm Beach on a northbound interstate highway is far from conclusive proof that they were heading directly to Bloomingdale.

 I have already indicated my view, supra, at 263-264, that such a “bare-bones” affidavit could not be the basis for a good-faith issuance of a warrant.

 Bridger v. State, 503 S. W. 2d 801 (Tex. Crim. App. 1974), and People v. Polariza, 55 Ill. App. 3d 1028, 371 N. E. 2d 687 (1978), which the Court describes ante, at 234, n. 9, appear to me to be excellent examples of overly technical applications of the Aguilar-Spinelli standard. The holdings in these cases could easily be disapproved without reliance on a “totality of the circumstances” analysis.