opinion: Mr. Justice Powell
  Court.
  delivered the opinion of the
  This case presents the question whether a witness summoned to appear and testify before a grand jury may refuse to answer questions on the ground that they are based on evidence obtained from an unlawful search and seizure. The issue is of considerable importance to the administration of criminal justice.
  I
  On December 11, 1970, federal agents obtained a warrant authorizing a search of respondent John Calan-dra’s place of business, the Royal Machine & Tool Co. in Cleveland, Ohio. The warrant was issued in connection with an extensive investigation of suspected illegal gambling operations. It specified that the object of the search was the discovery and seizure of bookmaking records and wagering paraphernalia. A master affidavit submitted in support of the application for the warrant contained information derived from statements by confidential informants to the Federal Bureau of Investigation (FBI), from physical surveillance conducted by FBI agents, and from court-authorized electronic surveillance.
  The Royal Machine & Tool Co. occupies a two-story building. The first floor consists of about 13,000 square feet, and houses industrial machinery and inventory. The second floor contains a general office area of about 1,500 square feet and a small office occupied by Calandra, president of the company, and his secretary. On December 15, 1970, federal agents executed the warrant directed at Calandra’s place of business and conducted a thorough, four-hour search of the premises. The record reveals that the agents spent more than three hours searching Calandra’s office and files.
  Although the agents found no gambling paraphernalia, one discovered, among certain promissory notes, a card indicating that Dr. Walter Loveland had been making periodic payments to Calandra. The agent stated in an affidavit that he was aware that the United States Attorney’s office for the Northern District of Ohio was investigating possible violations of 18 U. S. C. §§ 892, 893, and 894, dealing with extortionate credit transactions, and that Dr. Loveland had been the victim of a “loansharking” enterprise then under investigation. The agent concluded that the card bearing Dr. Loveland’s name was a loansharking record and therefore had it seized along with various other items, including books and records of the company, stock certificates, and. address books.
  On March 1, 1971, a special grand jury was convened in the Northern District of Ohio to investigate possible loansharking activities in violation of federal laws. The grand jury subpoenaed Calandra in order to ask him questions based on the evidence seized during the search of his place of business on December 15, 1970. Calandra appeared before the grand jury on August 17, 1971, but refused to testify, invoking his Fifth Amendment privilege against self-incrimination. The Government then requested the District Court to grant Calandra transactional immunity pursuant to 18 U. S. C. § 2514. Calandra requested and received a postponement of the hearing on the Government’s application for the immunity order so that he could prepare a motion to suppress the. evidence seized in the search.
  Calandra later moved pursuant to Fed. Rule Crim. Proc. 41 (e) for suppression and return of the seized evidence on the grounds that the affidavit supporting the' warrant was insufficient and that the search exceeded the scope of the warrant. On August 27, the District Court held a hearing at which Calandra stipulated that he would refuse to answer questions based on the seized materials. On October 1, the District Court entered its judgment ordering the evidence suppressed and returned to Calandra and further ordering that Calandra need not answer any of the grand jury’s questions based on the suppressed evidence. 332 F. Supp. 737 (1971). The court held that “due process . . . allows a witness to litigate the question of whether the evidence which constitutes the basis for the questions asked of him before the grand jury has been obtained in a way which violates the constitutional protection against unlawful search and seizure.” Id., at 742. The court found that the search warrant had been issued without probable cause and that the search had exceeded the scope of the warrant.
  The Court of Appeals for the Sixth Circuit affirmed, holding that the District Court had properly entertained the suppression motion and that the exclusionary rule may be invoked by a witness before the grand jury to bar questioning based on evidence obtained in an unlawful search and seizure. 465 F. 2d 1218 (1972). The offer to grant Calandra immunity was deemed irrelevant. Id., at 1221.
  We granted the Government’s petition for certiorari, 410 U. S. 925 (1973). We now reverse.
  I — I H-f
  The institution of the grand jury is deeply rooted in Anglo-American history. In England, the grand jury served for centuries both as a body of accusers sworn to discover and present for trial persons suspected of criminal wrongdoing and as a protector of citizens against arbitrary and oppressive governmental action. In this country the Founders thought the grand jury so essential to basic liberties that they provided in the Fifth Amendment that federal prosecution for serious crimes can only be instituted by “a presentment or indictment of a Grand Jury.” Cf. Costello v. United States, 350 U. S. 359, 361-362 (1956). The grand jury’s historic functions survive to this day. Its responsibilities continue to include both the determination whether there is probable cause to believe a crime has been committed and the protection of citizens against unfounded criminal prosecutions. Branzburg v. Hayes, 408 U. S. 665, 686-687 (1972).
  Traditionally the grand jury has been accorded wide latitude to inquire into violations of criminal law. No judge presides to monitor its proceedings. It deliberates in secret and may determine alone the course of its inquiry. The grand jury may compel the production of evidence or the testimony of witnesses as it considers appropriate, and its operation generally is unrestrained by the technical procedural and evidentiary rules governing the conduct of criminal trials. “It is a grand inquest, a body with powers of investigation and inquisition, the scope of whose inquiries is not to be limited narrowly by questions of propriety or forecasts of the probable result of the investigation, or by doubts whether any particular individual will be found properly subject to an accusation of crime.” Blair v. United States, 250 U. S. 273, 282 (1919).
  The scope of the grand jury’s powers reflects its special role in insuring fair and effective law enforcement. A grand jury proceeding is not an adversary hearing in which the guilt or innocence of the accused is adjudicated. Rather, it is an ex parte investigation to determine whether a crime has been committed and whether criminal proceedings should be instituted against any person. The grand jury’s investigative power must be broad if its public responsibility is adequately to be discharged. Branzburg v. Hayes, supra, at 700; Costello v. United States, supra, at 364.
  In Branzburg, the Court had occasion to reaffirm the importance of the grand jury’s role:
  “[T]he investigation of crime by the grand jury implements a fundamental governmental role of securing the safety of the person and property of the citizen . . . .” 408 U. S., at 700.
  “The role of the grand jury as an important instrument of effective law enforcement necessarily includes an investigatory function with respect to determining whether a crime has been committed and who committed it. . . . ‘When the grand jury is performing its investigatory function into a general problem area . . . society’s interest is best served by a thorough and extensive investigation.’ Wood v. Georgia, 370 U. S. 375, 392 (1962). A grand jury investigation ‘is not fully carried out until every available clue has been run down and all witnesses examined in every proper way to find if a crime has been committed.’ United States v. Stone, 429 F. 2d 138, 140 (CA2 1970). Such an investigation may be triggered by tips, rumors, evidence proffered by the prosecutor, or the personal knowledge of the grand jurors. Costello v. United States, 350 U. S., at 362. It is only after the grand jury has examined the evidence that a determination of whether the proceeding will result in an indictment can be made . . . .” Id., at 701-702.
  The grand jury’s sources of information are widely drawn, and the validity of an indictment is not affected by the character of the evidence considered. Thus, an indictment valid on its face is not subject to challenge on the ground that the grand jury acted on the basis of inadequate or incompetent evidence, Costello v. United States, supra; Holt v. United States, 218 U. S. 245 (1910); or even on the basis of information obtained in violation of a defendant’s Fifth Amendment privilege against self-incrimination, Lawn v. United States, 355 U. S. 339 (1958).
  The power of a federal court to compel persons to appear and testify before a grand jury is also firmly established. Kastigar v. United States, 406 U. S. 441 (1972). The duty to testify has long been recognized as a basic obligation that every citizen owes his Government. Blackmer v. United States, 284 U. S. 421, 438 (1932); United States v. Bryan, 339 U. S. 323, 331 (1950). In Branzburg v. Hayes, supra, at 682 and 688, the Court noted that “[c]itizens generally are not constitutionally immune from grand jury subpoenas . . .” and that “the longstanding principle that 'the public . . . has a right to every man’s evidence’ ... is particularly applicable to grand jury proceedings.” The duty to testify may on occasion be burdensome and even embarrassing. It may cause injury to a witness’ social and economic status. Yet the duty to testify has been regarded as “so necessary to the administration of justice” that the witness’ personal interest in privacy must yield to the public’s overriding interest in full disclosure. Blair v. United States, 250 U. S., at 281. Furthermore, a witness may not interfere with the course of the grand jury’s inquiry. He “is not entitled to urge objections of incompetency or irrelevancy, such as a party might raise, for this is no concern of his.” Id., at 282. Nor is he entitled “to challenge the authority of the court or of the grand jury” or “to set limits to the investigation that the grand jury may conduct.” Ibid.
  Of course, the grand jury’s subpoena power is not unlimited. It may consider incompetent evidence, but it may not itself violate a valid privilege, whether established by the Constitution, statutes, or the common law. Branzburg v. Hayes, supra; United States v. Bryan, supra; Blackmer v. United States, supra; 8 J. Wigmore, Evidence §§ 2290-2391 (McNaughton rev. ed. 1961). Although, for example, an indictment based on evidence obtained in violation of a defendant’s Fifth Amendment privilege is nevertheless valid, Lawn v. United States, supra, the grand jury may not force a witness to answer questions in violation of that constitutional guarantee. Rather, the grand jury may override a Fifth Amendment claim only if the witness is granted immunity co-extensive with the privilege against self-incrimination. Kastigar v. United States, supra. Similarly, a grand jury may not compel a person to produce books and papers that would incriminate him. Boyd v. United States, 116 U. S. 616, 633-635 (1886). Cf. Couch v. United States, 409 U. S. 322 (1973). The grand jury is also without power to invade a legitimate privacy interest protected by the Fourth Amendment. A grand jury’s subpoena duces tecum will be disallowed if it is “far too sweeping in its terms to' be regarded as reasonable” under the Fourth Amendment. Hale v. Henkel, 201 U. S. 43, 76 (1906). Judicial supervision is properly exercised in such cases to prevent the wrong before it occurs.
  III
  In the instant case, the Court of Appeals held that the exclusionary rule of the Fourth Amendment limits the grand jury's power to compel a witness to answer questions based on evidence obtained from a prior unlawful search and seizure. The exclusionary rule was adopted to effectuate the Fourth Amendment right of all citizens “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . Under this rule, evidence obtained in violation of the Fourth Amendment cannot be used in a criminal proceeding against the victim of the illegal search and seizure. Weeks v. United States, 232 U. S. 383 (1914); Mapp v. Ohio, 367 U. S. 643 (1961). This prohibition applies as well to the fruits of the illegally seized evidence. Wong Sun v. United States, 371 U. S. 471 (1963); Silverthorne Lumber Co. v. United States, 251 U. S. 385 (1920).
  The purpose of the exclusionary rule is not to redress the injury to the privacy of the search victim:
  “[T]he ruptured privacy of the victims’ homes and effects cannot be restored. Reparation comes too late.” Linkletter v. Walker, 381 U. S. 618, 637 (1965).
  Instead, the rule’s prime purpose is to deter future unlawful police conduct and thereby effectuate the guarantee of the Fourth Amendment against unreasonable searches and seizures: Accord, Mapp v. Ohio, supra, at 656; Tehan v. Shott, 382 U. S. 406, 416 (1966); Terry v. Ohio, 392 U. S. 1, 29 (1968). In sum, the rule is a judicially created remedy designed to safeguard Fourth Amendment rights generally through its deterrent effect, rather than a personal constitutional right of the party aggrieved.
  “The rule is calculated to prevent, not to repair. Its purpose is to deter — to compel respect for the constitutional guaranty in the only effectively available way — by removing the incentive to disregard it.” Elkins v. United States, 364 U. S. 206, 217 (1960).
  Despite its broad deterrent purpose, the exclusionary rule has never been interpreted to proscribe the use of illegally seized evidence in all proceedings or against all persons. As with any remedial device, the application of the rule has been restricted to those areas where its remedial objectives are thought most efficaciously served. The balancing process implicit in this approach is expressed in the contours of the standing requirement. Thus, standing to invoke the exclusionary rule has been confined to situations where the Government seeks to use such evidence to incriminate 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, supra; Jones v. United States, 362 U. S. 257 (1960). This standing rule is premised on a recognition that the need for deterrence and hence the rationale for excluding the evidence are strongest where the Government’s unlawful conduct would result in imposition of a criminal sanction on the victim of the search.
  IV
  In deciding whether to extend the exclusionary rule to grand jury proceedings, we must weigh the potential injury to the historic role and functions of the grand jury against the potential benefits of the rule as applied in this context. It is evident that this extention of the exclusionary rule would seriously impede the grand jury. Because the grand jury does not finally adjudicate guilt or innocence, it has traditionally been allowed to pursue its investigative and accusatorial functions unimpeded by the evidentiary and procedural restrictions applicable to a criminal trial. Permitting witnesses to invoke the exclusionary rule before a grand jury would precipitate adjudication of issues hitherto reserved for the trial on the merits and would delay and disrupt grand jury proceedings. Suppression hearings would halt the orderly progress of an investigation and might necessitate extended litigation of issues only tangentially related to the grand jury’s primary objective. The probable result would be “protracted interruption of grand jury proceedings,” Gelbard v. United States, 408 U. S. 41, 70 (1972) (White, J., concurring), effectively transforming them into preliminary trials on the merits. In some cases the delay might be fatal to the enforcement of the criminal law. Just last Term we reaffirmed our disinclination to allow litigious interference with grand jury proceedings:
  “Any holding that would saddle a grand jury with minitrials and preliminary showings would assuredly impede its investigation and frustrate the public’s interest in the fair and expeditious administration of the criminal laws.” United States v. Dionisio, 410 U. S. 1, 17 (1973).
  Cf. United States v. Ryan, 402 U. S. 530 (1971); Cobbledick v. United States, 309 U. S. 323 (1940). In sum, we believe that allowing a grand jury witness to invoke the exclusionary rule would unduly interfere with the effective and expeditious discharge of the grand jury’s duties.
  Against this potential damage to the role and functions of the grand jury, we must weigh the benefits to be derived from this proposed extension of the exclusionary rule. Suppression of the use of illegally seized evidence against the search victim in a criminal trial is thought to be an important method of effectuating the Fourth Amendment. But it does not follow that the Fourth Amendment requires adoption of every proposal that might deter police misconduct. In Alderman v. United States, 394 U. S., at 174-175, for example, this Court declined to extend the exclusionary rule to one who was not the victim of the unlawful search:
  “The deterrent values of preventing the incrimination of those whose rights the police have violated have been considered sufficient to justify the suppression of probative evidence even though the case against the defendant is weakened or destroyed. We adhere to that judgment. But we are not convinced that the additional benefits of extending the exclusionary rule to other defendants would justify further encroachment upon the public interest in prosecuting those accused of crime and having them acquitted or convicted on the basis of all the evidence which exposes the truth.”
  We think this observation equally applicable in the present context.
  Any incremental deterrent effect which might be achieved by extending the rule to grand jury proceedings is uncertain at best. Whatever deterrence of police misconduct may result from the exclusion of illegally seized evidence from criminal trials, it is unrealistic to assume that application of the rule to grand jury proceedings would significantly further that goal. Such an extension would deter only police investigation consciously directed toward the discovery of evidence solely for use in a grand jury investigation. The incentive to disregard the requirement of the Fourth Amendment solely to obtain an indictment from a grand jury is substantially negated by the inadmissibility of the illegally seized evidence in a subsequent criminal prosecution of the search victim. For the most part, a prosecutor would be unlikely to request an indictment where a conviction could not be obtained. 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.
  V
  Respondent also argues that each and every question based on evidence obtained from an illegal search and seizure constitutes a fresh and independent violation of the witness’ constitutional rights. Ordinarily, of course, a witness has no right of privacy before the grand jury. Absent some recognized privilege of confidentiality, every man owes his testimony. He may invoke his Fifth Amendment privilege against compulsory self-incrimination, but he may not decline to answer on the grounds that his responses might prove embarrassing or result in an unwelcome disclosure of his personal affairs. Blair v. United States, 250 U. S. 273 (1919). Respondent’s claim must be, therefore, not merely that the grand jury’s questions invade his privacy but that, because those questions are based on illegally obtained evidence, they somehow constitute distinct violations of his Fourth Amendment rights. We disagree.
  The purpose of the Fourth Amendment is to prevent unreasonable governmental intrusions into the privacy of one’s person, house, papers, or effects. The wrong condemned is the unjustified governmental invasion of these areas of an individual’s life. That wrong, committed in this case, is fully accomplished by the original search without probable cause. Grand jury questions based on evidence obtained thereby involve no independent governmental invasion of one’s person, house, papers, or effects, but rather the usual abridgment of personal privacy common to all grand jury questioning. Questions based on illegally obtained evidence are only a derivative use of the product of a past unlawful search and seizure. They work no new Fourth Amendment wrong. Whether such derivative use of illegally obtained evidence by a grand jury should be proscribed presents a question, not of rights, but of remedies.
  In the usual context of a criminal trial, the defendant is entitled to the suppression of, not only the evidence obtained through an unlawful search and seizure, but also any derivative use of that evidence. The prohibition of the exclusionary rule must reach such derivative use if it is to fulfill its function of deterring police misconduct. In the context of a grand jury proceeding, we believe that the damage to that institution from the unprecedented extension of the exclusionary rule urged by respondent outweighs the benefit of any possible incremental deterrent effect. Our conclusion necessarily controls both the evidence seized during the course of an unlawful search and seizure and any question or evidence derived therefrom (the fruits of the unlawful search). The same considerations of logic and policy apply to both the fruits of an unlawful search and seizure and derivative use of that evidence, and we do not distinguish between them.
  The judgment of the Court of Appeals is
  Reversed.
  On the basis of the same affidavit, federal agents also obtained warrants authorizing searches of Calandra’s residence and automobile. The present case involves only the search of the Royal Machine & Tool Co.
  The Court of Appeals affirmed the District Court’s finding that the search of Calandra’s business and seizure of his property were unlawful. 465 F. 2d 1218, 1226 n. 5. Although the Government does not agree with the court’s finding, it has not sought review of this issue. In addition, the Government has not challenged the District Court’s order directing return of the illegally seized property to Calandra.
  For a discussion of the history and role of the grand jury, see Costello v. United States, 350 U. S. 359, 361-362 (1956); Blair v. United States, 250 U. S. 273, 279-283 (1919); Hale v. Henkel, 201 U. S. 43, 59 (1906); 4 W. Blackstone, Commentaries *301 et seq.; G. Edwards, The Grand Jury 1-44 (1906); 1 F. Pollock & F. Maitland, History of English Law 151 (2d ed. 1909); 1 W. Holdsworth, History of English Law 321-323 (7th rev. ed. 1956).
  The grand jury is subject to the court’s supervision in several respects. See Brown v. United States, 359 U. S. 41, 49 (1959); Fed. Rules Crim. Proc. 6 and 17; 1 L. Orfield, Criminal Procedure Under the Federal Rules § 6:108, pp. 475-477 (1966). In particular, the grand jury must rely on the court to compel production of books, papers, documents, and the testimony of witnesses, and the court may quash or modify a subpoena on motion if compliance would be “unreasonable or oppressive.” Fed. Rule Crim. Proc. 17 (c).
  There is some disagreement as to the practical efficacy of the exclusionary rule, and as the Court noted in Elkins v. United States, 364 U. S. 206, 218 (1960), relevant “[ejmpirical statistics are not available.” Cf. Oaks, Studying the Exclusionary Rule in Search and Seizure, 37 U. Chi. L. Rev. 665 (1970). We have no occasion in the present case to consider the extent of the rule’s efficacy in criminal trials.
  In holding that the respondent had standing to invoke the exclusionary rule in a grand jury proceeding, the Court of Appeals relied on Fed. Rule Crim. Proc. 41 (e). 465 F. 2d, at 1222-1224. Rule 41 (e) provides, in relevant part, that “[a] person aggrieved by an unlawful search and seizure may move the district court ... for the return of the property and to suppress for the use as evidence anything so obtained . . . .” It further states that “[t]he motion shall be made before trial or hearing . . . .” We have recognized that Rule 41 (e) is “no broader than the constitutional rule.” Alderman v. United States, 394 U. S. 165, 173 n. 6 (1969); Jones v. United States, 362 U. S. 257 (1960). Rule 41 (e), therefore, does not constitute a statutory expansion of the exclusionary rule.
  The Court of Appeals also found that the Government’s offer of immunity under 18 U. S. C. § 2514 was irrelevant to respondent’s standing to invoke the exclusionary rule. 465 F. 2d, at 1221. We agree with that determination for the' reasons stated in Parts III, IV, and V of this opinion.
  The force of this argument is well illustrated by the facts of the present case. As of the date of this decision, almost two and one-half years will have elapsed since respondent was summoned to appear and testify before the grand jury. If respondent’s testimony was vital to the grand jury’s investigation in August 1971 of extortionate credit transactions, it is possible that this particular investigation has been completely frustrated.
  Respondent relies primarily on Silverthorne Lumber Co. v. United States, 251 U. S. 385 (1920), which the dissent contends “plainly controls this case.” Post, at 362. In that ease, federal officers unlawfully seized certain documents belonging to the Silverthornes and their lumber company and presented them to a grand jury that had already indicted the Silverthornes and the company. A district court ordered the return of the documents but impounded photographs and copies of the originals. Later, the prosecutor caused the grand jury to issue subpoenas duces tecum to the Silverthornes and the company to produce the originals, and their refusal to comply led to a contempt citation. In reversing the judgment, the Court held that the subpoenas were invalid because they were based on knowledge obtained from the illegally seized evidence, citing Weeks v. United States, 232 U. S. 383 (1914). Mr. Justice Holmes, writing for the Court, stated that the “essence of a provision forbidding the acquisition of evidence in a certain way is that not merely evidence so acquired shall not be used before the Court but that it shall not be used at all.” 251 U. S., at 392.
  Silverthorne is distinguishable from the present case in several significant respects. There, plaintiffs in error had previously been indicted by the grand jury and.thus could invoke the exclusionary rule on the basis of their status as criminal defendants. Moreover, the Government’s interest in recapturing the original documents was founded on a belief that they might be useful in the criminal prosecution already authorized by the grand jury. It did not appear that the grand jury needed the documents to perform its investigative or accusatorial functions. Thus, the primary consequence of the Court’s decision was to exclude the evidence from the subsequent criminal trial. Finally, prior to the issuance of the grand jury subpoenas, there had been a judicial determination that the search and seizure were illegal. The claim of plaintiffs in error was not raised for the first time in a pre-indictment motion to suppress requiring interruption of grand jury proceedings.
  By contrast, in the instant case respondent had not been indicted by the grand jury and was not a criminal defendant. Under traditional principles, he had no standing to invoke the exclusionary rule. The effect of the District Court’s order was to deprive the grand jury of testimony it needed to conduct its investigation. Furthermore, respondent’s motion to suppress had not been previously made and required interruption of the grand jury proceedings. In these circumstances, Silverthorne is certainly not controlling. To the extent that the Court’s broad dictum might be construed to suggest a different result in the present case, we note that it has been substantially undermined by later eases. See Parts III and IV of this opinion.
  At oral argument, counsel for respondent stated the contention as follows:
  “I submit to the Court that each question asked of the Respondent before the Grand Jury, which question was only asked because of a past violation of the Fourth Amendment, [amounts to] a new, immediate violation of the Fourth Amendment .... [A] question derived from a past violation, a question into the privacy of the witness amounts to another intrusion in violation of the Fourth Amendment.” Tr. of Oral Arg. 17.
  “[Rjefusing to answer a question in which the question conceivably is derived from a past violation of the Fourth Amendment, gives rise to an additional or new Fourth Amendment right to resist answering that question because the question itself becomes an additional intrusion . . . .” Tr. of Oral Arg. 19-20.
  It should be noted that, even absent the exclusionary rule, a grand jury witness may have other remedies to redress the injury to his privacy and to prevent a further invasion in the future. He may be entitled to maintain a cause of action for damages against the officers who conducted the unlawful search. Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388 (1971). He may also seek return of the illegally seized property, and exclusion of the property and its fruits from being used as evidence against him in a criminal trial. Go-Bart Importing Co. v. United States, 282 U. S. 344 (1931). In these circumstances, we cannot say that such a witness is necessarily left remediless in the face of an unlawful search and seizure.
  The dissent's reliance on Gelbard v. United States, 408 U. S. 41 (1972), is misplaced. There, the Court construed 18 U. S. C. § 2515, the evidentiary prohibition of Tit. Ill of the Omnibus Crime Control and Safe Streets Act of 1968, 82 Stat. 211, as amended, 18 U. S. C. §§ 2510-2520. It held that § 2515 could be invoked by a grand jury witness as a defense to a contempt charge brought for refusal to answer questions based on information obtained from the witness’ communications alleged to have been unlawfully intercepted through wiretapping and electronic surveillance. The Court’s holding rested exclusively on an interpretation of Tit. Ill, which represented a congressional effort to afford special safeguards against the unique problems posed by misuse of wiretapping and electronic surveillance. There was no indication, in either Gelbard or the legislative history, that Tit. Ill was regarded as a restatement of existing law with respect to grand jury proceedings. As Mr. Justice White noted in his concurring opinion in Gelbard, Tit. Ill “unquestionably works a change in the law with respect to the rights of grand jury witnesses . . . .” 408 U. S., at 70.
  The dissent also voices concern that today’s decision will betray “ ‘the imperative of judicial integrity,’ ” sanction “illegal government conduct,” and even “imperil the very foundation of our people’s trust in their Government.” Post, at 360. There is no basis for this alarm. “Illegal conduct” is hardly sanctioned, nor are the foundations of the Republic imperiled, by declining to make an unprecedented extension of the exclusionary rule to grand jury proceedings where the rule’s objectives would not be effectively served and where other important and historic values would be unduly prejudiced. Cf. Alderman v. United States, 394 U. S. 165 (1969); Linkletter v. Walker, 381 U. S. 618 (1965); and cases cited supra, at 347-348.