åíËã ÇáÝÞì
04-04-2009, 12:30 AM
Syllabus
Where it is feasible, a syllabus (headnote) will be NOTE: released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321 .
SUPREME COURT OF THE UNITED STATES
HERRING v. UNITED STATES
certiorari to the united states court of appeals for the eleventh circuit
Argued October 7, 2008—Decided January 14, 2009 No. 07–513.
Officers in Coffee County arrested petitioner Herring based on a warrant listed in neighboring Dale County’s database. A search incident to that arrest yielded drugs and a gun. It was then revealed that the warrant had been recalled months earlier, though this information had never been entered into the database. Herring was indicted on federal gun and drug possession charges and moved to suppress the evidence on the ground that his initial arrest had been illegal. Assuming that there was a Fourth Amendment violation, the District Court concluded that the exclusionary rule did not apply and denied the motion to suppress. The Eleventh Circuit affirmed, finding that the arresting officers were innocent of any wrongdoing, and that Dale County’s failure to update the records was merely negligent. The court therefore concluded that the benefit of suppression would be marginal or nonexistent and that the evidence was admissible under the good-faith rule of United States v. Leon, 468 U. S. 897 .
Held: When police mistakes leading to an unlawful search are the result of isolated negligence attenuated from the search, rather than systemic error or reckless disregard of constitutional requirements, the exclusionary rule does not apply. Pp. 4–13.
(a) The fact that a search or arrest was unreasonable does not necessarily mean that the exclusionary rule applies. Illinois v. Gates, 462 U. S. 213 . The rule is not an individual right and applies only where its deterrent effect outweighs the substantial cost of letting guilty and possibly dangerous defendants go free. Leon, 468 U. S., at 908–909. For example, it does not apply if police acted “in objectively reasonable reliance” on an invalid warrant. Id., at 922. In applying Leon’s good-faith rule to police who reasonably relied on mistaken information in a court’s database that an arrest warrant was outstanding, Arizona v. Evans, 514 U. S. 1 , the Court left unresolved the issue confronted here: whether evidence should be suppressed if the police committed the error, id., at 16, n. 5. Pp. 4–7.
(b) The extent to which the exclusionary rule is justified by its deterrent effect varies with the degree of law enforcement culpability. See, e.g., Leon, supra, at 911. Indeed, the abuses that gave rise to the rule featured intentional conduct that was patently unconstitutional. See, e.g., Weeks v. United States, 232 U. S 383. An error arising from nonrecurring and attenuated negligence is far removed from the core concerns that led to the rule’s adoption. Pp. 7–9.
(c) To trigger the exclusionary rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it, and sufficiently culpable that such deterrence is worth the price paid by the justice system. The pertinent analysis is objective, not an inquiry into the arresting officers’ subjective awareness. See, e.g., Leon, supra, at 922, n. 23. Pp. 9–11.
(d) The conduct here was not so objectively culpable as to require exclusion. The marginal benefits that might follow from suppressing evidence obtained in these circumstances cannot justify the substantial costs of exclusion. Leon, supra, at 922. Pp. 11–13.
492 F. 3d 1212, affirmed.
Roberts, C. J., delivered the opinion of the Court, in which Scalia, Kennedy, Thomas, and Alito, JJ., joined. Ginsburg, J., filed a dissenting opinion, in which Stevens, Souter, and Breyer, JJ., joined. Breyer, J., filed a dissenting opinion, in which Souter, J., joined.
Chief Justice Roberts, Opinion of the Court
This opinion is subject to formal revision before NOTICE: publication in the preliminary print of the United States Readers are requested to notify the Reporter of Decisions, Reports. Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order that corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
BENNIE DEAN HERRING, PETITIONER v. UNITED
STATES
on writ of certiorari to the united states court of appeals for the eleventh circuit
[January 14, 2009]
Chief Justice Roberts delivered the opinion of the Court.
The Fourth Amendment forbids “unreasonable searches and seizures,” and this usually requires the police to have probable cause or a warrant before making an arrest. What if an officer reasonably believes there is an outstanding arrest warrant, but that belief turns out to be wrong because of a negligent bookkeeping error by another police employee? The parties here agree that the ensuing arrest is still a violation of the Fourth Amendment , but dispute whether contraband found during a search incident to that arrest must be excluded in a later prosecution.
Our cases establish that such suppression is not an automatic consequence of a Fourth Amendment violation. Instead, the question turns on the culpability of the police and the potential of exclusion to deter wrongful police conduct. Here the error was the result of isolated negligence attenuated from the arrest. We hold that in these circumstances the jury should not be barred from considering all the evidence.
I
On July 7, 2004, Investigator Mark Anderson learned that Bennie Dean Herring had driven to the Coffee County Sheriff’s Department to retrieve something from his impounded truck. Herring was no stranger to law enforcement, and Anderson asked the county’s warrant clerk, Sandy Pope, to check for any outstanding warrants for Herring’s arrest. When she found none, Anderson asked Pope to check with Sharon Morgan, her counterpart in neighboring Dale County. After checking Dale County’s computer database, Morgan replied that there was an active arrest warrant for Herring’s failure to appear on a felony charge. Pope relayed the information to Anderson and asked Morgan to fax over a copy of the warrant as confirmation. Anderson and a deputy followed Herring as he left the impound lot, pulled him over, and arrested him. A search incident to the arrest revealed methamphetamine in Herring’s pocket, and a pistol (which as a felon he could not possess) in his vehicle. App. 17–23.
There had, however, been a mistake about the warrant. The Dale County sheriff’s computer records are supposed to correspond to actual arrest warrants, which the office also maintains. But when Morgan went to the files to retrieve the actual warrant to fax to Pope, Morgan was unable to find it. She called a court clerk and learned that the warrant had been recalled five months earlier. Normally when a warrant is recalled the court clerk’s office or a judge’s chambers calls Morgan, who enters the information in the sheriff’s computer database and disposes of the physical copy. For whatever reason, the information about the recall of the warrant for Herring did not appear in the database. Morgan immediately called Pope to alert her to the mixup, and Pope contacted Anderson over a secure radio. This all unfolded in 10 to 15 minutes, but Herring had already been arrested and found with the gun and drugs, just a few hundred yards from the sheriff’s office. Id., at 26, 35–42, 54–55.
Herring was indicted in the District Court for the Middle District of Alabama for illegally possessing the gun and drugs, violations of 18 U. S. C. §922(g)(1) and 21 U. S. C. §844(a). He moved to suppress the evidence on the ground that his initial arrest had been illegal because the warrant had been rescinded. The Magistrate Judge recommended denying the motion because the arresting officers had acted in a good-faith belief that the warrant was still outstanding. Thus, even if there were a Fourth Amendment violation, there was “no reason to believe that application of the exclusionary rule here would deter the occurrence of any future mistakes.” App. 70. The District Court adopted the Magistrate Judge’s recommendation, 451 F. Supp. 2d 1290 (2005), and the Court of Appeals for the Eleventh Circuit affirmed, 492 F. 3d 1212 (2007).
The Eleventh Circuit found that the arresting officers in Coffee County “were entirely innocent of any wrongdoing or carelessness.” id., at 1218. The court assumed that whoever failed to update the Dale County sheriff’s records was also a law enforcement official, but noted that “the conduct in question [wa]s a negligent failure to act, not a deliberate or tactical choice to act.” Ibid. Because the error was merely negligent and attenuated from the arrest, the Eleventh Circuit concluded that the benefit of suppressing the evidence “would be marginal or nonexistent,” ibid. (internal quotation marks omitted), and the evidence was therefore admissible under the good-faith rule of United States v. Leon, 468 U. S. 897 (1984) .
Other courts have required exclusion of evidence obtained through similar police errors, e.g., Hoay v. State, 348 Ark. 80, 86–87, 71 S. W. 3d 573, 577 (2002), so we granted Herring’s petition for certiorari to resolve the conflict, 552 U. S. ___ (2008). We now affirm the Eleventh Circuit’s judgment.
II
When a probable-cause determination was based on reasonable but mistaken assumptions, the person subjected to a search or seizure has not necessarily been the victim of a constitutional violation. The very phrase “probable cause” confirms that the Fourth Amendment does not demand all possible precision. And whether the error can be traced to a mistake by a state actor or some other source may bear on the analysis. For purposes of deciding this case, however, we accept the parties’ assumption that there was a Fourth Amendment violation. The issue is whether the exclusionary rule should be applied.
A
The Fourth Amendment protects “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,” but “contains no provision expressly precluding the use of evidence obtained in violation of its commands,” Arizona v. Evans, 514 U. S. 1, 10 (1995) . Nonetheless, our decisions establish an exclusionary rule that, when applicable, forbids the use of improperly obtained evidence at trial. See, e.g., Weeks v. United States, 232 U. S. 383, 398 (1914) . We have stated that this judicially created rule is “designed to safeguard Fourth Amendment rights generally through its deterrent effect.” United States v. Calandra, 414 U. S. 338, 348 (1974) .
In analyzing the applicability of the rule, Leon admonished that we must consider the actions of all the police officers involved. 468 U. S., at 923, n. 24 (“It is necessary to consider the objective reasonableness, not only of the officers who eventually executed a warrant, but also of the officers who originally obtained it or who provided information material to the probable-cause determination”). The Coffee County officers did nothing improper. Indeed, the error was noticed so quickly because Coffee County requested a faxed confirmation of the warrant.
The Eleventh Circuit concluded, however, that somebody in Dale County should have updated the computer database to reflect the recall of the arrest warrant. The court also concluded that this error was negligent, but did not find it to be reckless or deliberate. 492 F. 3d, at 1218. 1That fact is crucial to our holding that this error is not enough by itself to require “the extreme sanction of exclusion.” Leon, supra, at 916.
B
The fact that a 1. Fourth Amendment violation occurred—i.e., that a search or arrest was unreasonable—does not necessarily mean that the exclusionary rule applies. Illinois v. Gates, 462 U. S. 213, 223 (1983) . Indeed, exclusion “has always been our last resort, not our first impulse,” Hudson v. Michigan, 547 U. S. 586, 591 (2006) , and our precedents establish important principles that constrain application of the exclusionary rule.
First, the exclusionary rule is not an individual right and applies only where it “ ‘result[s] in appreciable deterrence.’ ” Leon, supra, at 909 (quoting United States v. Janis, 428 U. S. 433, 454 (1976) ). We have repeatedly rejected the argument that exclusion is a necessary consequence of a Fourth Amendment violation. Leon, supra, at 905–906; Evans, supra, at 13–14; Pennsylvania Bd. of Probation and Parole v. Scott, 524 U. S. 357, 363 (1998) . Instead we have focused on the efficacy of the rule in deterring Fourth Amendment violations in the future. See Calandra, supra, at 347–355; Stone v. Powell, 428 U. S. 465, 486 (1976) .1
In addition, the benefits of deterrence must outweigh the costs. Leon, supra, at 910. “We have never suggested that the exclusionary rule must apply in every circumstance in which it might provide marginal deterrence.” Scott, supra, at 368. “[T]o the extent that application of the exclusionary rule could provide some incremental deterrent, that possible benefit must be weighed against [its] substantial social costs.” Illinois v. Krull, 480 U. S. 340, 352–353 (1987) (internal quotation marks omitted). The principal cost of applying the rule is, of course, letting guilty and possibly dangerous defendants go free—something that “offends basic concepts of the criminal justice system.” Leon, supra, at 908. “[T]he rule’s costly toll upon truth-seeking and law enforcement objectives presents a high obstacle for those urging [its] application.” Scott, supra, at 364–365 (internal quotation marks omitted); see also United States v. Havens, 446 U. S. 620, 626–627 (1980) ; United States v. Payner, 447 U. S. 727, 734 (1980) .
These principles are reflected in the holding of Leon: When police act under a warrant that is invalid for lack of probable cause, the exclusionary rule does not apply if the police acted “in objectively reasonable reliance” on the subsequently invalidated search warrant. 468 U. S.,at 922. We (perhaps confusingly) called this objectively reasonable reliance “good faith.” Ibid., n. 23. In a companion case, Massachusetts v. Sheppard, 468 U. S. 981 (1984) , we held that the exclusionary rule did not apply when a warrant was invalid because a judge forgot to make “clerical corrections” to it. Id., at 991.
Shortly thereafter we extended these holdings to warrantless administrative searches performed in good-faith reliance on a statute later declared unconstitutional. Krull, supra, at 349–350. Finally, in Evans, 514 U. S. 1 , we applied this good-faith rule to police who reasonably relied on mistaken information in a court’s database that an arrest warrant was outstanding. We held that a mistake made by a judicial employee could not give rise to exclusion for three reasons: The exclusionary rule was crafted to curb police rather than judicial misconduct; court employees were unlikely to try to subvert the Fourth Amendment ; and “most important, there [was] no basis for believing that application of the exclusionary rule in [those] circumstances” would have any significant effect in deterring the errors. Id., at 15. Evans left unresolved “whether the evidence should be suppressed if police personnel were responsible for the error,” 3an issue not argued by the State in that case, id., at 16, n. 5, but one that we now confront.
The extent to which the exclusionary rule is 2. justified by these deterrence principles varies with the culpability of the law enforcement conduct. As we said in Leon, “an assessment of the flagrancy of the police misconduct constitutes an important step in the calculus” of applying the exclusionary rule. 468 U. S., at 911. Similarly, in Krull we elaborated that “evidence 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 .’ ” 480 U. S., at 348–349 (quoting United States v. Peltier, 422 U. S. 531, 542 (1975) ). Anticipating the good-faith exception to the exclusionary rule, Judge Friendly wrote that “[t]he beneficent aim of the exclusionary rule to deter police misconduct can be sufficiently accomplished by a practice . . . outlawing evidence obtained by flagrant or deliberate violation of rights.” The Bill of Rights as a Code of Criminal Procedure, 53 Calif. L. Rev. 929, 953 (1965) (footnotes omitted); see also Brown v. Illinois, 422 U. S. 590, 610–611 (1975) (Powell, J., concurring in part) (“[T]he deterrent value of the exclusionary rule is most likely to be effective” when “official conduct was flagrantly abusive of Fourth Amendment rights”).
Where it is feasible, a syllabus (headnote) will be NOTE: released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321 .
SUPREME COURT OF THE UNITED STATES
HERRING v. UNITED STATES
certiorari to the united states court of appeals for the eleventh circuit
Argued October 7, 2008—Decided January 14, 2009 No. 07–513.
Officers in Coffee County arrested petitioner Herring based on a warrant listed in neighboring Dale County’s database. A search incident to that arrest yielded drugs and a gun. It was then revealed that the warrant had been recalled months earlier, though this information had never been entered into the database. Herring was indicted on federal gun and drug possession charges and moved to suppress the evidence on the ground that his initial arrest had been illegal. Assuming that there was a Fourth Amendment violation, the District Court concluded that the exclusionary rule did not apply and denied the motion to suppress. The Eleventh Circuit affirmed, finding that the arresting officers were innocent of any wrongdoing, and that Dale County’s failure to update the records was merely negligent. The court therefore concluded that the benefit of suppression would be marginal or nonexistent and that the evidence was admissible under the good-faith rule of United States v. Leon, 468 U. S. 897 .
Held: When police mistakes leading to an unlawful search are the result of isolated negligence attenuated from the search, rather than systemic error or reckless disregard of constitutional requirements, the exclusionary rule does not apply. Pp. 4–13.
(a) The fact that a search or arrest was unreasonable does not necessarily mean that the exclusionary rule applies. Illinois v. Gates, 462 U. S. 213 . The rule is not an individual right and applies only where its deterrent effect outweighs the substantial cost of letting guilty and possibly dangerous defendants go free. Leon, 468 U. S., at 908–909. For example, it does not apply if police acted “in objectively reasonable reliance” on an invalid warrant. Id., at 922. In applying Leon’s good-faith rule to police who reasonably relied on mistaken information in a court’s database that an arrest warrant was outstanding, Arizona v. Evans, 514 U. S. 1 , the Court left unresolved the issue confronted here: whether evidence should be suppressed if the police committed the error, id., at 16, n. 5. Pp. 4–7.
(b) The extent to which the exclusionary rule is justified by its deterrent effect varies with the degree of law enforcement culpability. See, e.g., Leon, supra, at 911. Indeed, the abuses that gave rise to the rule featured intentional conduct that was patently unconstitutional. See, e.g., Weeks v. United States, 232 U. S 383. An error arising from nonrecurring and attenuated negligence is far removed from the core concerns that led to the rule’s adoption. Pp. 7–9.
(c) To trigger the exclusionary rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it, and sufficiently culpable that such deterrence is worth the price paid by the justice system. The pertinent analysis is objective, not an inquiry into the arresting officers’ subjective awareness. See, e.g., Leon, supra, at 922, n. 23. Pp. 9–11.
(d) The conduct here was not so objectively culpable as to require exclusion. The marginal benefits that might follow from suppressing evidence obtained in these circumstances cannot justify the substantial costs of exclusion. Leon, supra, at 922. Pp. 11–13.
492 F. 3d 1212, affirmed.
Roberts, C. J., delivered the opinion of the Court, in which Scalia, Kennedy, Thomas, and Alito, JJ., joined. Ginsburg, J., filed a dissenting opinion, in which Stevens, Souter, and Breyer, JJ., joined. Breyer, J., filed a dissenting opinion, in which Souter, J., joined.
Chief Justice Roberts, Opinion of the Court
This opinion is subject to formal revision before NOTICE: publication in the preliminary print of the United States Readers are requested to notify the Reporter of Decisions, Reports. Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order that corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
BENNIE DEAN HERRING, PETITIONER v. UNITED
STATES
on writ of certiorari to the united states court of appeals for the eleventh circuit
[January 14, 2009]
Chief Justice Roberts delivered the opinion of the Court.
The Fourth Amendment forbids “unreasonable searches and seizures,” and this usually requires the police to have probable cause or a warrant before making an arrest. What if an officer reasonably believes there is an outstanding arrest warrant, but that belief turns out to be wrong because of a negligent bookkeeping error by another police employee? The parties here agree that the ensuing arrest is still a violation of the Fourth Amendment , but dispute whether contraband found during a search incident to that arrest must be excluded in a later prosecution.
Our cases establish that such suppression is not an automatic consequence of a Fourth Amendment violation. Instead, the question turns on the culpability of the police and the potential of exclusion to deter wrongful police conduct. Here the error was the result of isolated negligence attenuated from the arrest. We hold that in these circumstances the jury should not be barred from considering all the evidence.
I
On July 7, 2004, Investigator Mark Anderson learned that Bennie Dean Herring had driven to the Coffee County Sheriff’s Department to retrieve something from his impounded truck. Herring was no stranger to law enforcement, and Anderson asked the county’s warrant clerk, Sandy Pope, to check for any outstanding warrants for Herring’s arrest. When she found none, Anderson asked Pope to check with Sharon Morgan, her counterpart in neighboring Dale County. After checking Dale County’s computer database, Morgan replied that there was an active arrest warrant for Herring’s failure to appear on a felony charge. Pope relayed the information to Anderson and asked Morgan to fax over a copy of the warrant as confirmation. Anderson and a deputy followed Herring as he left the impound lot, pulled him over, and arrested him. A search incident to the arrest revealed methamphetamine in Herring’s pocket, and a pistol (which as a felon he could not possess) in his vehicle. App. 17–23.
There had, however, been a mistake about the warrant. The Dale County sheriff’s computer records are supposed to correspond to actual arrest warrants, which the office also maintains. But when Morgan went to the files to retrieve the actual warrant to fax to Pope, Morgan was unable to find it. She called a court clerk and learned that the warrant had been recalled five months earlier. Normally when a warrant is recalled the court clerk’s office or a judge’s chambers calls Morgan, who enters the information in the sheriff’s computer database and disposes of the physical copy. For whatever reason, the information about the recall of the warrant for Herring did not appear in the database. Morgan immediately called Pope to alert her to the mixup, and Pope contacted Anderson over a secure radio. This all unfolded in 10 to 15 minutes, but Herring had already been arrested and found with the gun and drugs, just a few hundred yards from the sheriff’s office. Id., at 26, 35–42, 54–55.
Herring was indicted in the District Court for the Middle District of Alabama for illegally possessing the gun and drugs, violations of 18 U. S. C. §922(g)(1) and 21 U. S. C. §844(a). He moved to suppress the evidence on the ground that his initial arrest had been illegal because the warrant had been rescinded. The Magistrate Judge recommended denying the motion because the arresting officers had acted in a good-faith belief that the warrant was still outstanding. Thus, even if there were a Fourth Amendment violation, there was “no reason to believe that application of the exclusionary rule here would deter the occurrence of any future mistakes.” App. 70. The District Court adopted the Magistrate Judge’s recommendation, 451 F. Supp. 2d 1290 (2005), and the Court of Appeals for the Eleventh Circuit affirmed, 492 F. 3d 1212 (2007).
The Eleventh Circuit found that the arresting officers in Coffee County “were entirely innocent of any wrongdoing or carelessness.” id., at 1218. The court assumed that whoever failed to update the Dale County sheriff’s records was also a law enforcement official, but noted that “the conduct in question [wa]s a negligent failure to act, not a deliberate or tactical choice to act.” Ibid. Because the error was merely negligent and attenuated from the arrest, the Eleventh Circuit concluded that the benefit of suppressing the evidence “would be marginal or nonexistent,” ibid. (internal quotation marks omitted), and the evidence was therefore admissible under the good-faith rule of United States v. Leon, 468 U. S. 897 (1984) .
Other courts have required exclusion of evidence obtained through similar police errors, e.g., Hoay v. State, 348 Ark. 80, 86–87, 71 S. W. 3d 573, 577 (2002), so we granted Herring’s petition for certiorari to resolve the conflict, 552 U. S. ___ (2008). We now affirm the Eleventh Circuit’s judgment.
II
When a probable-cause determination was based on reasonable but mistaken assumptions, the person subjected to a search or seizure has not necessarily been the victim of a constitutional violation. The very phrase “probable cause” confirms that the Fourth Amendment does not demand all possible precision. And whether the error can be traced to a mistake by a state actor or some other source may bear on the analysis. For purposes of deciding this case, however, we accept the parties’ assumption that there was a Fourth Amendment violation. The issue is whether the exclusionary rule should be applied.
A
The Fourth Amendment protects “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,” but “contains no provision expressly precluding the use of evidence obtained in violation of its commands,” Arizona v. Evans, 514 U. S. 1, 10 (1995) . Nonetheless, our decisions establish an exclusionary rule that, when applicable, forbids the use of improperly obtained evidence at trial. See, e.g., Weeks v. United States, 232 U. S. 383, 398 (1914) . We have stated that this judicially created rule is “designed to safeguard Fourth Amendment rights generally through its deterrent effect.” United States v. Calandra, 414 U. S. 338, 348 (1974) .
In analyzing the applicability of the rule, Leon admonished that we must consider the actions of all the police officers involved. 468 U. S., at 923, n. 24 (“It is necessary to consider the objective reasonableness, not only of the officers who eventually executed a warrant, but also of the officers who originally obtained it or who provided information material to the probable-cause determination”). The Coffee County officers did nothing improper. Indeed, the error was noticed so quickly because Coffee County requested a faxed confirmation of the warrant.
The Eleventh Circuit concluded, however, that somebody in Dale County should have updated the computer database to reflect the recall of the arrest warrant. The court also concluded that this error was negligent, but did not find it to be reckless or deliberate. 492 F. 3d, at 1218. 1That fact is crucial to our holding that this error is not enough by itself to require “the extreme sanction of exclusion.” Leon, supra, at 916.
B
The fact that a 1. Fourth Amendment violation occurred—i.e., that a search or arrest was unreasonable—does not necessarily mean that the exclusionary rule applies. Illinois v. Gates, 462 U. S. 213, 223 (1983) . Indeed, exclusion “has always been our last resort, not our first impulse,” Hudson v. Michigan, 547 U. S. 586, 591 (2006) , and our precedents establish important principles that constrain application of the exclusionary rule.
First, the exclusionary rule is not an individual right and applies only where it “ ‘result[s] in appreciable deterrence.’ ” Leon, supra, at 909 (quoting United States v. Janis, 428 U. S. 433, 454 (1976) ). We have repeatedly rejected the argument that exclusion is a necessary consequence of a Fourth Amendment violation. Leon, supra, at 905–906; Evans, supra, at 13–14; Pennsylvania Bd. of Probation and Parole v. Scott, 524 U. S. 357, 363 (1998) . Instead we have focused on the efficacy of the rule in deterring Fourth Amendment violations in the future. See Calandra, supra, at 347–355; Stone v. Powell, 428 U. S. 465, 486 (1976) .1
In addition, the benefits of deterrence must outweigh the costs. Leon, supra, at 910. “We have never suggested that the exclusionary rule must apply in every circumstance in which it might provide marginal deterrence.” Scott, supra, at 368. “[T]o the extent that application of the exclusionary rule could provide some incremental deterrent, that possible benefit must be weighed against [its] substantial social costs.” Illinois v. Krull, 480 U. S. 340, 352–353 (1987) (internal quotation marks omitted). The principal cost of applying the rule is, of course, letting guilty and possibly dangerous defendants go free—something that “offends basic concepts of the criminal justice system.” Leon, supra, at 908. “[T]he rule’s costly toll upon truth-seeking and law enforcement objectives presents a high obstacle for those urging [its] application.” Scott, supra, at 364–365 (internal quotation marks omitted); see also United States v. Havens, 446 U. S. 620, 626–627 (1980) ; United States v. Payner, 447 U. S. 727, 734 (1980) .
These principles are reflected in the holding of Leon: When police act under a warrant that is invalid for lack of probable cause, the exclusionary rule does not apply if the police acted “in objectively reasonable reliance” on the subsequently invalidated search warrant. 468 U. S.,at 922. We (perhaps confusingly) called this objectively reasonable reliance “good faith.” Ibid., n. 23. In a companion case, Massachusetts v. Sheppard, 468 U. S. 981 (1984) , we held that the exclusionary rule did not apply when a warrant was invalid because a judge forgot to make “clerical corrections” to it. Id., at 991.
Shortly thereafter we extended these holdings to warrantless administrative searches performed in good-faith reliance on a statute later declared unconstitutional. Krull, supra, at 349–350. Finally, in Evans, 514 U. S. 1 , we applied this good-faith rule to police who reasonably relied on mistaken information in a court’s database that an arrest warrant was outstanding. We held that a mistake made by a judicial employee could not give rise to exclusion for three reasons: The exclusionary rule was crafted to curb police rather than judicial misconduct; court employees were unlikely to try to subvert the Fourth Amendment ; and “most important, there [was] no basis for believing that application of the exclusionary rule in [those] circumstances” would have any significant effect in deterring the errors. Id., at 15. Evans left unresolved “whether the evidence should be suppressed if police personnel were responsible for the error,” 3an issue not argued by the State in that case, id., at 16, n. 5, but one that we now confront.
The extent to which the exclusionary rule is 2. justified by these deterrence principles varies with the culpability of the law enforcement conduct. As we said in Leon, “an assessment of the flagrancy of the police misconduct constitutes an important step in the calculus” of applying the exclusionary rule. 468 U. S., at 911. Similarly, in Krull we elaborated that “evidence 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 .’ ” 480 U. S., at 348–349 (quoting United States v. Peltier, 422 U. S. 531, 542 (1975) ). Anticipating the good-faith exception to the exclusionary rule, Judge Friendly wrote that “[t]he beneficent aim of the exclusionary rule to deter police misconduct can be sufficiently accomplished by a practice . . . outlawing evidence obtained by flagrant or deliberate violation of rights.” The Bill of Rights as a Code of Criminal Procedure, 53 Calif. L. Rev. 929, 953 (1965) (footnotes omitted); see also Brown v. Illinois, 422 U. S. 590, 610–611 (1975) (Powell, J., concurring in part) (“[T]he deterrent value of the exclusionary rule is most likely to be effective” when “official conduct was flagrantly abusive of Fourth Amendment rights”).