Respondent, the chief investigator for a district attorney’s office, testified at grand jury proceedings that resulted in petitioner’s indictment. After the indictments were dismissed, petitioner brought an action under 42 U. S. C. §1983, alleging that respondent had conspired to present and did present false testimony to the grand jury. The Federal District Court denied respondent’s motion to dismiss on immunity grounds, but the Eleventh Circuit reversed, holding that respondent had absolute immunity from a §1983 claim based on his grand jury testimony.

Held: A witness in a grand jury proceeding is entitled to the same absolute immunity from suit under §1983 as a witness who testifies at trial. Pp. 3–18.

(a) Section 1983, which derives from §1 of the Civil Rights Act of 1871, was not meant to effect a radical departure from ordinary tort law and the common-law immunities applicable in tort suits. See, e.g., Burns v. Reed, 500 U. S. 478. This interpretation of §1983 has been reaffirmed by the Court time and again. Thus, the Court looks to the common law for guidance in determining the scope of the immunities available in actions brought under §1983. See Kalina v. Fletcher, 522 U. S. 118. Taking a “functional approach,” see, e.g., Forrester v. White, 484 U. S. 219, the Court identifies those governmental functions that were historically viewed as so important and vulnerable to interference by means of litigation that some form of absolute immunity from civil liability was needed to ensure that they are “ ‘performed with independence and without fear of consequences,’ ” Pierson v. Ray, 386 U. S. 547.

The Court’s functional approach is tied to the common law’s identification of functions meriting the protection of absolute immunity, but the Court’s precedents have not mechanically duplicated the precise scope of the absolute immunity the common law provided to protect those functions. For example, it was common in 1871 for cases to be prosecuted by private parties, who did not enjoy absolute immunity from suit. But as the prosecutorial function was increasingly assumed by public officials, common-law courts held that public prosecutors, unlike their private predecessors, were absolutely immune from the types of tort claims that an aggrieved or vengeful criminal defendant was most likely to assert. This adaptation of prosecutorial immunity accommodated the special needs of public, as opposed to private, prosecutors. Thus, when the issue of prosecutorial immunity under §1983 reached this Court in Imbler v. Pachtman, 424 U. S. 409, the Court did not simply apply the scope of immunity recognized by common-law courts as of 1871 but instead relied substantially on post-1871 cases extending broad immunity to public prosecutors sued for common-law torts. Neither has the Court suggested that §1983 is simply a federalized amalgamation of pre-existing common-law claims. The new federal claim created by §1983 differs in important ways from pre-existing common-law torts. Accordingly, both the scope of the new tort and the scope of the absolute immunity available in §1983 actions differ in some respects from the common law. Pp. 3―9.

(b) A trial witness sued under §1983 enjoys absolute immunity from any claim based on his testimony. Briscoe v. LaHue, 460 U. S. 352. Without absolute immunity, the truth-seeking process would be impaired as witnesses might be reluctant to testify, and even a witness who took the stand “might be inclined to shade his testimony in favor of the potential plaintiff” for “fear of subsequent liability.” Id., at 333. These factors apply with equal force to grand jury witnesses. In both contexts, a witness’ fear of retaliatory litigation may deprive the tribunal of critical evidence. And in neither context is the deterrent of potential civil liability needed to prevent false testimony because other sanctions, chiefly prosecution for perjury, provide a sufficient deterrent.

For the reasons identified in Briscoe, supra, at 342–344, there is no reason to distinguish law enforcement witnesses from lay witnesses in §1983 actions. And the rule that a grand jury witness has absolute immunity from any §1983 claim based on the witness’ testimony may not be circumvented by claiming that a grand jury witness conspired to present false testimony, or by using evidence of the witness’ testimony to support any other §1983 claim concerning the initiation or maintenance of a prosecution. Were it otherwise, a criminal defendant turned civil plaintiff could reframe a claim to attack the preparatory activity—such as a preliminary discussion in which the witness relates the substance of his intended testimony—rather than the absolutely immune actions themselves. Pp. 9−12.

(c) Petitioner’s main argument is that under Malley v. Briggs, 475 U. S. 335−341, and Kalina v. Fletcher, 522 U. S. 118, grand jury witnesses who are “complaining witnesses” are not entitled to absolute immunity. But at the time §1983’s predecessor was enacted, a “complaining witness” was a party who procured an arrest and initiated a criminal prosecution. A “complaining witness” might testify, either before a grand jury or at trial, but testifying was not a necessary characteristic of a “complaining witness.” Thus, testifying, whether before a grand jury or at trial, was not the distinctive function performed by a “complaining witness.” A “complaining witness” cannot be held liable for perjurious trial testimony, see Briscoe, 460 U. S., at 326, and there is no more reason why a “complaining witness” should be subject to liability for testimony before a grand jury.

Once the distinctive function performed by a “complaining witness” is understood, it is apparent that a law enforcement officer who testifies before a grand jury is not comparable to a “complaining witness” because it is not the officer who makes the critical decision to press criminal charges, but the prosecutor. It would be anomalous to permit a police officer testifying before a grand jury to be sued for maliciously procuring an unjust prosecution when it is the prosecutor, who is shielded by absolute immunity, who is actually responsible for the decision to initiate a prosecution. Petitioner also contends that the deterrent effect of civil liability is more needed in grand jury proceedings because trial witnesses face cross-examination. But the force of that argument is more than offset by the problem that allowing such civil actions would create—subversion of grand jury secrecy, which is essential to the proper functioning of the grand jury system. See United States v. Sells Engineering, Inc., 463 U. S. 418. And finally, contrary to petitioner’s suggestion, recognizing absolute immunity for grand jury witnesses does not create an insupportable distinction between States that use grand juries and States that permit felony prosecutions to be brought by complaint or information. Most States that do not require an indictment for felonies provide a preliminary hearing at which witnesses testify, and the lower courts have held that preliminary hearing witnesses are protected by the same immunity accorded grand jury witnesses. Pp. 12−18.

611 F. 3d 828, affirmed.

Alito, J., delivered the opinion for a unanimous Court.

Petitioner was arrested during a traffic stop by a New Jersey state trooper who checked a statewide computer database and found a bench warrant issued for petitioner’s arrest after he failed to appear at a hearing to enforce a fine. He was initially detained in the Burlington County Detention Center and later in the Essex County Correctional Facility, but was released once it was determined that the fine had been paid. At the first jail, petitioner, like every incoming detainee, had to shower with a delousing agent and was checked for scars, marks, gang tattoos, and contraband as he disrobed. Petitioner claims that he also had to open his mouth, lift his tongue, hold out his arms, turn around, and lift his genitals. At the second jail, petitioner, like other arriving detainees, had to remove his clothing while an officer looked for body markings, wounds, and contraband; had an officer look at his ears, nose, mouth, hair, scalp, fingers, hands, armpits, and other body openings; had a mandatory shower; and had his clothes examined. Petitioner claims that he was also required to lift his genitals, turn around, and cough while squatting. He filed a 42 U. S. C. §1983 action in the Federal District Court against the government entities that ran the jails and other defendants, alleging Fourth and Fourteenth Amendment violations, and arguing that persons arrested for minor offenses cannot be subjected to invasive searches unless prison officials have reason to suspect concealment of weapons, drugs, or other contraband. The court granted him summary judgment, ruling that “strip-searching” nonindictable offenders without reasonable suspicion violates the Fourth Amendment. The Third Circuit reversed.

Held: The judgment is affirmed.

621 F. 3d 296, affirmed.

Justice Kennedy delivered the opinion of the Court, except as to Part IV, concluding that the search procedures at the county jails struck a reasonable balance between inmate privacy and the needs of the institutions, and thus the Fourth and Fourteenth Amendments do not require adoption of the framework and rules petitioner pro- poses. Pp. 5−18, 19.

(a) Maintaining safety and order at detention centers requires the expertise of correctional officials, who must have substantial discretion to devise reasonable solutions to problems. A regulation impinging on an inmate’s constitutional rights must be upheld “if it is reasonably related to legitimate penological interests.” Turner v. Safley, 482 U. S. 78. This Court, in Bell v. Wolfish, 441 U. S. 520, upheld a rule requiring pretrial detainees in federal correctional facilities “to expose their body cavities for visual inspection as a part of a strip search conducted after every contact visit with a person from outside the institution[s],” deferring to the judgment of correctional officials that the inspections served not only to discover but also to deter the smuggling of weapons, drugs, and other prohibited items. In Block v. Rutherford, 468 U. S. 576−587, the Court upheld a general ban on contact visits in a county jail, noting the smuggling threat posed by such visits and the difficulty of carving out exceptions for certain detainees. The Court, in Hudson v. Palmer, 468 U. S. 517−523, also recognized that deterring the possession of contraband depends in part on the ability to conduct searches without predictable exceptions when it upheld the constitutionality of random searches of inmate lockers and cells even without suspicion that an inmate is concealing a prohibited item. These cases establish that correctional officials must be permitted to devise reasonable search policies to detect and deter the possession of contraband in their facilities, and that “in the absence of substantial evidence in the record to indicate that the officials have exaggerated their response to these considerations courts should ordinarily defer to their expert judgment in such matters,” Block, supra, at 584–585.

Persons arrested for minor offenses may be among the detainees to be processed at jails. See Atwater v. Lago Vista, 532 U. S. 318. Pp. 5−9.

(b) The question here is whether undoubted security imperatives involved in jail supervision override the assertion that some detainees must be exempt from the invasive search procedures at issue absent reasonable suspicion of a concealed weapon or other contraband. Correctional officials have a significant interest in conducting a thorough search as a standard part of the intake process. The admission of new inmates creates risks for staff, the existing detainee population, and the new detainees themselves. Officials therefore must screen for contagious infections and for wounds or injuries requiring immediate medical attention. It may be difficult to identify and treat medical problems until detainees remove their clothes for a visual inspection. Jails and prisons also face potential gang violence, giving them reasonable justification for a visual inspection of detainees for signs of gang affiliation as part of the intake process. Additionally, correctional officials have to detect weapons, drugs, alcohol, and other prohibited items new detainees may possess. Drugs can make inmates aggressive toward officers or each other, and drug trading can lead to violent confrontations. Contraband has value in a jail’s culture and underground economy, and competition for scarce goods can lead to violence, extortion, and disorder. Pp. 9−13.

(c) Petitioner’s proposal―that new detainees not arrested for serious crimes or for offenses involving weapons or drugs be exempt from invasive searches unless they give officers a particular reason to suspect them of hiding contraband―is unworkable. The seriousness of an offense is a poor predictor of who has contraband, and it would be difficult to determine whether individual detainees fall within the proposed exemption. Even persons arrested for a minor offense may be coerced by others into concealing contraband. Exempting people arrested for minor offenses from a standard search protocol thus may put them at greater risk and result in more contraband being brought into the detention facility.

It also may be difficult to classify inmates by their current and prior offenses before the intake search. Jail officials know little at the outset about an arrestee, who may be carrying a false ID or lie about his identity. The officers conducting an initial search often do not have access to criminal history records. And those records can be inaccurate or incomplete. Even with accurate information, officers would encounter serious implementation difficulties. They would be required to determine quickly whether any underlying offenses were serious enough to authorize the more invasive search protocol. Other possible classifications based on characteristics of individual detainees also might prove to be unworkable or even give rise to charges of discriminatory application. To avoid liability, officers might be inclined not to conduct a thorough search in any close case, thus creating unnecessary risk for the entire jail population. While the restrictions petitioner suggests would limit the intrusion on the privacy of some detainees, it would be at the risk of increased danger to everyone in the facility, including the less serious offenders. The Fourth and Fourteenth Amendments do not require adoption of the proposed framework. Pp. 13−18, 19.

Kennedy, J., delivered the opinion of the Court, except as to Part IV. Roberts, C. J., and Scalia and Alito, JJ., joined that opinion in full, and Thomas, J., joined as to all but Part IV. Roberts, C. J., and Alito, J., filed concurring opinions. Breyer, J., filed a dissenting opinion, in which Ginsburg, Sotomayor, and Kagan, JJ., joined.