misconduct is outweighed by expense of impeding role of grand jury).

In Leon, the Court held that the exclusionary rule should not be applied to evidence obtained by a police officer whose reliance on a search warrant issued by a neutral magistrate was objectively reasonable, even though the warrant was ultimately found to be defective. On the basis of three factors, the Court concluded that there was no sound reason to apply the exclusionary rule as a means of deterring misconduct on the part of judicial officers who are responsible for issuing warrants. First, the exclusionary rule was historically designed "to deter police misconduct rather than to punish the errors of judges and magistrates." 468 U. S., at 916. Second, there was "no evidence suggesting that judges and magistrates are inclined to ignore or subvert the Fourth Amendment or that lawlessness among these actors requires application of the extreme sanction of exclusion." Ibid. Third, and of greatest importance to the Court, there was no basis "for believing that exclusion of evidence seized pursuant to a warrant will have a significant deterrent effect on the issuing judge or magistrate." Ibid. The Court explained: "Judges and magistrates are not adjuncts to the law enforcement team; as neutral judicial officers, they have no stake in the outcome of particular criminal prosecutions." Id., at 917. Thus, the threat of exclusion of evidence could not be expected to deter such individuals from improperly issuing warrants, and a judicial ruling that a warrant was defective was sufficient to inform the judicial officer of the error made.

The Court then considered whether application of the exclusionary rule in that context could be expected to alter the behavior of law enforcement officers. In prior cases, the Court had observed that, because the purpose of the exclusionary rule is to deter police officers from violating the Fourth Amendment, 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." United States v. Peltier, 422 U. S. 531, 542 (1975); see also Michigan v. Tucker, 417 U. S. 433, 447 (1974). Where the officer's conduct is objectively reasonable, the Court explained in Leon,

"[e]xcluding the evidence will not further the ends of the exclusionary rule in any appreciable way; for it is painfully apparent that . . . the officer is acting as a reasonable officer would and should act in similar circumstances. Excluding the evidence can in no way affect his future conduct unless it is to make him less willing to do his duty."" United States v. Leon, 468 U. S., at 920, quoting Stone v. Powell, 428 U. S., at 539-540 (WHITE, J., dissenting).

The Court in Leon concluded that a deterrent effect was particularly absent when an officer, acting in objective good faith, obtained a search warrant from a magistrate and acted within its scope. "In most such cases, there is no police illegality and thus nothing to deter." 468 U. S., at 920-921. It is the judicial officer's responsibility to determine whether probable cause exists to issue a warrant, and, in the ordinary case, police officers cannot be expected to question that determination. Because the officer's sole responsibility after obtaining a warrant is to carry out the search pursuant to it, applying the exclusionary rule in these circumstances could have no deterrent effect on a future Fourth Amendment violation by the officer. Id., at 921.

B

The approach used in Leon is equally applicable to the present case. The application of the exclusionary rule to suppress evidence obtained by an officer acting in objectively reasonable reliance on a statute would have as little deterrent effect on the officer's actions as would the exclusion of evidence when an officer acts in objectively reasonable reliance on a warrant. Unless a statute is clearly unconstitutional, an

officer cannot be expected to question the judgment of the legislature that passed the law. If the statute is subsequently declared unconstitutional, excluding evidence obtained pursuant to it prior to such a judicial declaration will not deter future Fourth Amendment violations by an officer who has simply fulfilled his responsibility to enforce the statute as written. To paraphrase the Court's comment in Leon: "Penalizing the officer for the [legislature's] error, rather than his own, cannot logically contribute to the deterrence of Fourth Amendment violations." Ibid."

Any difference between our holding in Leon and our holding in the instant case, therefore, must rest on a difference between the effect of the exclusion of evidence on judicial officers and the effect of the exclusion of evidence on legislators. Although these two groups clearly serve different functions in the criminal justice system, those differences are not controlling for purposes of this case. We noted in Leon as an initial matter that the exclusionary rule was aimed at deterring police misconduct. 468 U. S., at 916. Thus, legislators, like judicial officers, are not the focus of the rule. Moreover, to the extent we consider the rule's effect on legislators, our initial inquiry, as set out in Leon, is whether there is evidence to suggest that legislators "are inclined to ignore or subvert the Fourth Amendment." Ibid. Although legislators are not "neutral judicial officers," as are judges and magistrates, id., at 917, neither are they "adjuncts to the

'Indeed, the possibility of a deterrent effect may be even less when the officer acts pursuant to a statute rather than a warrant. In Leon, the Court pointed out: "One could argue that applying the exclusionary rule in cases where the police failed to demonstrate probable cause in the warrant application deters future inadequate presentations or 'magistrate shopping' and thus promotes the ends of the Fourth Amendment." 468 U. S., at 918. Although the Court in Leon dismissed that argument as speculative, ibid., the possibility that a police officer might modify his behavior does not exist at all when the officer relies on an existing statute that authorizes warrantless inspections and does not require any preinspection action, comparable to seeking a warrant, on the part of the officers.

law enforcement team." Ibid. The role of legislators in the criminal justice system is to enact laws for the purpose of establishing and perpetuating that system. In order to fulfill this responsibility, legislators' deliberations of necessity are significantly different from the hurried judgment of a law enforcement officer "engaged in the often competitive enterprise of ferreting out crime." Johnson v. United States, 333 U. S. 10, 14 (1948). Before assuming office, state legislators are required to take an oath to support the Federal Constitution. See U. S. Const., Art. VI, cl. 3. Indeed, by according laws a presumption of constitutional validity, courts presume that legislatures act in a constitutional manner. e. g., McDonald v. Board of Election Comm'rs of Chicago, 394 U. S. 802, 808-809 (1969); see generally 1 N. Singer, Sutherland on Statutory Construction §2.01 (4th ed. 1985).

See

There is no evidence suggesting that Congress or state legislatures have enacted a significant number of statutes permitting warrantless administrative searches violative of the Fourth Amendment. Legislatures generally have confined their efforts to authorizing administrative searches of specific categories of businesses that require regulation, and the resulting statutes usually have been held to be constitutional. See, e. g., Donovan v. Dewey, 452 U. S. 594 (1981); United States v. Biswell, 406 U. S. 311 (1972); Colonnade Catering Corp. v. United States, 397 U. S. 72 (1970); United States v. Jamieson-McKames Pharmaceuticals, Inc., 651 F. 2d 532 (CA8 1981), cert. denied, 455 U. S. 1016 (1982); see also 3 W. LaFave, Search and Seizure § 10.2, pp. 132-134, n. 89.1 (Supp. 1986) (collecting cases). Thus, we are given no basis for believing that legislators are inclined to subvert their oaths and the Fourth Amendment and that "lawlessness among these actors requires application of the extreme sanction of exclusion." United States v. Leon, 468 U. S., at 916.

Even if we were to conclude that legislators are different in certain relevant respects from magistrates, because legislators are not officers of the judicial system, the next inquiry

necessitated by Leon is whether exclusion of evidence seized pursuant to a statute subsequently declared unconstitutional will "have a significant deterrent effect," ibid., on legislators enacting such statutes. Respondents have offered us no reason to believe that applying the exclusionary rule will have such an effect. Legislators enact statutes for broad, programmatic purposes, not for the purpose of procuring evidence in particular criminal investigations. Thus, it is logical to assume that the greatest deterrent to the enactment of unconstitutional statutes by a legislature is the power of the courts to invalidate such statutes. Invalidating a statute informs the legislature of its constitutional error, affects the admissibility of all evidence obtained subsequent to the constitutional ruling, and often results in the legislature's enacting a modified and constitutional version of the statute, as happened in this very case. There is nothing to indicate that applying the exclusionary rule to evidence seized pursuant to the statute prior to the declaration of its invalidity will act as a significant, additional deterrent. Moreover, to the extent that application of the exclusionary rule could provide some incremental deterrent, that possible benefit must be weighed against the "substantial social costs exacted by the exclusion

It is possible, perhaps, that there are some legislators who, for political purposes, are possessed with a zeal to enact a particular unconstitutionally restrictive statute, and who will not be deterred by the fact that a court might later declare the law unconstitutional. But we doubt whether a legislator possessed with such fervor, and with such disregard for his oath to support the Constitution, would be significantly deterred by the possibility that the exclusionary rule would preclude the introduction of evidence in a certain number of prosecutions. Moreover, and of equal importance, just as we were not willing to assume in Leon that the possibility of magistrates' acting as "rubber stamps for the police" was a problem of major proportions, see 468 U. S., at 916, n. 14, we are not willing to assume now that there exists a significant problem of legislators who perform their legislative duties with indifference to the constitutionality of the statutes they enact. If future empirical evidence ever should undermine that assumption, our conclusions may be revised accordingly. See United States v. Leon, 468 U. S., at 927-928 (concurring opinion).