opinion: Justice Ginsburg
  delivered the opinion of the Court.
  In Gerstein v. Pugh, 420 U. S. 103 (1975), we held that the Fourth Amendment’s shield against unreasonable seizures requires a prompt judicial determination of probable cause following an arrest made without a warrant and ensuing detention. County of Riverside v. McLaughlin, 500 U. S. 44 (1991), established that “prompt” generally means within 48 hours of the warrantless arrest; absent extraordinary circumstances, a longer delay violates the Fourth Amendment. In the case now before us, the Supreme Court of Nevada stated that McLaughlin does not apply to a prosecution commenced prior to the rendition of that decision. We hold that the Nevada Supreme Court misread this Court’s precedent: “[A]... rule for the conduct of criminal prosecutions is to be applied retroactively to all cases, state or federal,... not yet final” when the rule is announced. Griffith v. Kentucky, 479 U. S. 314, 328 (1987).
  I
  Petitioner Kitrich Powell was arrested on Friday, November 3, 1989, for felony child abuse of his girlfriend’s 4-year-old daughter, in violation of Nev. Rev. Stat. § 200.508 (1991). That afternoon, the arresting officer prepared a sworn declaration describing the cause for and circumstances of the arrest. Not until November 7, 1989, however, did a Magistrate find probable cause to hold Powell for a preliminary hearing. That same day, November 7, Powell made statements to the police, prejudicial to him, which the prosecutor later presented at Powell’s trial. Powell was not personally brought before a Magistrate until November 13, 1989. By that time, the child had died of her injuries, and Powell was charged additionally with her murder.
  A jury found Powell guilty of first-degree murder and, following a penalty hearing, sentenced him to death. On appeal to the Nevada Supreme Court, Powell argued that the State had violated Nevada’s “initial appearance” statute by failing to bring him before a magistrate within 72 hours, and that his conviction should therefore be reversed.
  The Nevada statute governing appearances before a magistrate provides:
  “If an arrested person is not brought before a magistrate within 72 hours after arrest, excluding nonjudicial days, the magistrate:
  “(a) Shall give the prosecuting attorney an opportunity to explain the circumstances leading to the delay; and
  “(b) May release the arrested person if he determines that the person was not brought before a magistrate without unnecessary delay.” Nev. Rev. Stat. §171.178(3) (1991).
  Powell emphasized that 10 days had elapsed between his arrest on November 3, 1989, and his November 13 initial .appearance before a Magistrate. In view of the incriminating statements he made on November 7, Powell contended, the unlawful delay was prejudicial to him. Under Nevada law, Powell asserted, vindication of his right to a speedy first appearance required that his conviction be reversed, and that he be set free. Appellant’s Opening Brief in No. 22348 (Nev.), p. 85.
  The district attorney maintained before the Nevada Supreme Court that there had been no fatal violation of Nevada’s initial appearance statute. First, the district attorney urged, the confirmation of probable cause by a Magistrate on November 7 occurred within 72 hours of the November 3 arrest (excluding the intervening weekend). This probable-cause finding, the district attorney contended, satisfied the 72-hour prescription of Nev. Rev. Stat. §171.178. In any event, the district attorney continued, under Nevada law, an accused waives his right to a speedy arraignment when he voluntarily waives his right to remain silent and his right to counsel. Powell did so, the district attorney said, when he made his November 7 statements, after he was read his Miranda rights and waived those rights. See Respondent’s Answering Brief in No. 22348 (Nev.), pp. 56-60. In reply, Powell vigorously contested the district attorney’s portrayal of the probable-cause determination as tantamount to an initial appearance sufficient to satisfy Nev. Rev. Stat. § 171.178’s 72-hour prescription. Powell pointed out that he “was neither present [n]or advised of the magistrate’s finding.” Appellant’s Reply Brief in No. 22348 (Nev.), p. 1.
  The Nevada Supreme Court concluded, in accord with the district attorney’s assertion, that Powell had waived his right under state law to a speedy arraignment. 108 Nev. 700, 705, 838 P. 2d 921, 924-925 (1992). If the Nevada Supreme Court had confined the decision to that point, its opinion would have resolved no federal issue. But the Nevada Supreme Court said more. Perhaps in response to the district attorney’s contention that the Magistrate’s November 7 probable-cause notation satisfied Nev. Rev. Stat. §171.178 (a contention the State now disavows), the Nevada Supreme Court, sua sponte, raised a federal concern. That court detoured from its state-law analysis to inquire whether the November 3 to November 7,1989, delay, in judicial confirmation of probable cause violated the Fourth Amendment under this Court’s precedents.
  County of Riverside v. McLaughlin, 500 U. S. 44 (1991), the Nevada Supreme Court recognized, made specific the probable-cause promptness requirement of Gerstein v. Pugh, 420 U. S. 103 (1975); McLaughlin instructed that a delay exceeding 48 hours presumptively violates the Fourth Amendment. Merging the speedy initial appearance required by Nevada statute and the prompt probable-cause determination required by the Fourth Amendment, the Nevada Supreme Court declared: “The McLaughlin case renders [Nev. Rev. Stat. § ]171.178(3) unconstitutional insofar [as] it permits an initial appearance up to seventy-two hours after arrest and instructs that non-judicial days be excluded from the calculation of those hours.” 108 Nev., at 705, 838 R 2d, at 924. While instructing that, henceforth, probable-cause determinations be made within 48 hours of a suspect’s arrest, the Nevada Supreme Court held McLaughlin inapplicable “to the case at hand,” because that recent precedent postdated Powell’s arrest. 108 Nev., at 705, n. 1, 838 P. 2d, at 924, n. 1. McLaughlin announced a new rule, the Nevada Supreme Court observed, and therefore need not be applied retroactively. 108 Nev., at 705, n. 1, 838 P. 2d, at 924, n. 1.
  Powell petitioned for our review raising the question whether a state court may decline to apply a recently rendered Fourth Amendment decision of this Court to a case pending on direct appeal. We granted certiorari, 510 U. S. 811 (1993), and now reject the state court’s prospectivity declaration.
  II
  Powell’s arrest was not validated by a magistrate until four days elapsed. That delay was presumptively unreasonable under McLaughlin’s 48-hour rule. The State so concedes. Appellee’s Answer to Petition for Rehearing in No. 22348 (Nev.), p. 7; Tr. of Oral Arg. 28. The State further concedes that the Nevada Supreme Court’s retroactivity analysis was incorrect. See ibid. We held in Griffith v. Kentucky, 479 U. S., at 328, that “a new rule for the conduct of criminal prosecutions is to be applied retroactively to all cases, state or federal, pending on direct review or not yet final.” Griffith stressed two points. First, “the nature of judicial review . . . precludes us from ‘[s]imply fishing one case from the stream of appellate review, using it as a vehicle for pronouncing new constitutional standards, and then permitting a stream of similar cases subsequently to flow by unaffected by that new rule.’” Id., at 323 (quoting Mackey v. United States, 401 U. S. 667, 679 (1971) (Harlan, J., concurring in judgment)). Second, “selective application of new rules violates the principle of treating similarly situated defendants the same.” Griffith, supra, at 323. Assuming, arguendo, that the 48-hour presumption announced in McLaughlin qualifies as a “new rule,” cf. Teague v. Lane, 489 U. S. 288, 299-310 (1989), Griffith nonetheless entitles Powell to rely on McLaughlin for this simple reason: Powell’s conviction was not final when McLaughlin was announced.
  It does not necessarily follow, however, that Powell must “be set free,” 108 Nev., at 705, n. 1, 838 P. 2d, at 924, n. 1, or gain other relief, for several questions remain open for decision on remand. In particular, the Nevada Supreme Court has not yet closely considered the appropriate remedy for a delay in determining probable cause (an issue not resolved by McLaughlin), or the consequences of Powell’s failure to raise the federal question, or the district attorney’s argument that introduction at trial of what Powell said on November 7, 1989, was “harmless” in view of a similar, albeit shorter, statement Powell made on November 3, prior to his arrest. See Brief for Respondent 22. Expressing no opinion on these issues, we hold only that the Nevada Supreme Court erred in failing to recognize that Griffith v. Kentucky calls for retroactive application of McLaughlin’s 48-hour rule.
  * * *
  For the reasons stated, the judgment of the Nevada Supreme Court is vacated, and the case is remanded for further proceedings not inconsistent with this opinion.
  It is so ordered.
  Justice Thomas would reach out and decide the first of these questions, though it is not presented in the petition for review. He would rule inappropriate “suppression of [Powell’s November 7] statement ... because the statement was not a product of the McLaughlin violation.” Post, at 89. It is “settled law,” he maintains, post, at 88, that if probable cause in fact existed for Powell’s detention, then McLaughlin’s 48-hour rule, though violated, triggers no suppression remedy. Quite the opposite, Justice Thomas recognizes, is “settled law” regarding search warrants: A court’s postsearch validation of probable cause will not render the evidence admissible. See Vale v. Louisiana, 399 U. S. 30, 35, 34 (1970) (absent circumstances justifying a warrantless search, it is “constitutional error [to] admi[t] into evidence the fruits of the illegal search,” “even though the authorities ha[d] probable cause to conduct it”).
  Justice Thomas maintains, however, that our precedents, especially New York v. Harris, 495 U. S. 14 (1990), already establish that no suppression is required in Powell’s case. In Harris, we held that violation of the Fourth Amendment’s rule against warrantless arrests in a dwelling, see Payton v. New York, 445 U. S. 573 (1980), generally does not lead to the suppression of a postarrest confession. But Powell does not complain of police failure to obtain a required arrest warrant. He targets a different constitutional violation — failure to obtain authorization from a magistrate for a significant period of pretrial detention. Whether a suppression remedy applies in that setting remains an unresolved question. Because the issue was not raised, argued, or decided below, we should not settle it here.
choices: attorney general of the United States, or his office specified state board or department of education city, town, township, village, or borough government or governmental unit state commission, board, committee, or authority county government or county governmental unit, except school district court or judicial district state department or agency governmental employee or job applicant female governmental employee or job applicant minority governmental employee or job applicant minority female governmental employee or job applicant not listed among agencies in the first Administrative Action variable retired or former governmental employee U.S. House of Representatives interstate compact judge state legislature, house, or committee local governmental unit other than a county, city, town, township, village, or borough governmental official, or an official of an agency established under an interstate compact state or U.S. supreme court local school district or board of education U.S. Senate U.S. senator foreign nation or instrumentality state or local governmental taxpayer, or executor of the estate of state college or university United States State person accused, indicted, or suspected of crime advertising business or agency agent, fiduciary, trustee, or executor airplane manufacturer, or manufacturer of parts of airplanes airline distributor, importer, or exporter of alcoholic beverages alien, person subject to a denaturalization proceeding, or one whose citizenship is revoked American Medical Association National Railroad Passenger Corp. amusement establishment, or recreational facility arrested person, or pretrial detainee attorney, or person acting as such;includes bar applicant or law student, or law firm or bar association author, copyright holder bank, savings and loan, credit union, investment company bankrupt person or business, or business in reorganization establishment serving liquor by the glass, or package liquor store water transportation, stevedore bookstore, newsstand, printer, bindery, purveyor or distributor of books or magazines brewery, distillery broker, stock exchange, investment or securities firm construction industry bus or motorized passenger transportation vehicle business, corporation buyer, purchaser cable TV car dealer person convicted of crime tangible property, other than real estate, including contraband chemical company child, children, including adopted or illegitimate religious organization, institution, or person private club or facility coal company or coal mine operator computer business or manufacturer, hardware or software consumer, consumer organization creditor, including institution appearing as such; e.g., a finance company person allegedly criminally insane or mentally incompetent to stand trial defendant debtor real estate developer disabled person or disability benefit claimant distributor person subject to selective service, including conscientious objector drug manufacturer druggist, pharmacist, pharmacy employee, or job applicant, including beneficiaries of employer-employee trust agreement, employee health and welfare fund, or multi-employer pension plan electric equipment manufacturer electric or hydroelectric power utility, power cooperative, or gas and electric company eleemosynary institution or person environmental organization employer. If employer's relations with employees are governed by the nature of the employer's business (e.g., railroad, boat), rather than labor law generally, the more specific designation is used in place of Employer. farmer, farm worker, or farm organization father female employee or job applicant female movie, play, pictorial representation, theatrical production, actor, or exhibitor or distributor of fisherman or fishing company food, meat packing, or processing company, stockyard foreign (non-American) nongovernmental entity franchiser franchisee lesbian, gay, bisexual, transexual person or organization person who guarantees another's obligations handicapped individual, or organization of devoted to health organization or person, nursing home, medical clinic or laboratory, chiropractor heir, or beneficiary, or person so claiming to be hospital, medical center husband, or ex-husband involuntarily committed mental patient Indian, including Indian tribe or nation insurance company, or surety inventor, patent assigner, trademark owner or holder investor injured person or legal entity, nonphysically and non-employment related juvenile government contractor holder of a license or permit, or applicant therefor magazine male medical or Medicaid claimant medical supply or manufacturing co. racial or ethnic minority employee or job applicant minority female employee or job applicant manufacturer management, executive officer, or director, of business entity military personnel, or dependent of, including reservist mining company or miner, excluding coal, oil, or pipeline company mother auto manufacturer newspaper, newsletter, journal of opinion, news service radio and television network, except cable tv nonprofit organization or business nonresident nuclear power plant or facility owner, landlord, or claimant to ownership, fee interest, or possession of land as well as chattels shareholders to whom a tender offer is made tender offer oil company, or natural gas producer elderly person, or organization dedicated to the elderly out of state noncriminal defendant political action committee parent or parents parking lot or service patient of a health professional telephone, telecommunications, or telegraph company physician, MD or DO, dentist, or medical society public interest organization physically injured person, including wrongful death, who is not an employee pipe line company package, luggage, container political candidate, activist, committee, party, party member, organization, or elected official indigent, needy, welfare recipient indigent defendant private person prisoner, inmate of penal institution professional organization, business, or person probationer, or parolee protester, demonstrator, picketer or pamphleteer (non-employment related), or non-indigent loiterer public utility publisher, publishing company radio station racial or ethnic minority person or organization protesting racial or ethnic segregation or discrimination racial or ethnic minority student or applicant for admission to an educational institution realtor journalist, columnist, member of the news media resident restaurant, food vendor retarded person, or mental incompetent retired or former employee railroad private school, college, or university seller or vendor shipper, including importer and exporter shopping center, mall spouse, or former spouse stockholder, shareholder, or bondholder retail business or outlet student, or applicant for admission to an educational institution taxpayer or executor of taxpayer's estate, federal only tenant or lessee theater, studio forest products, lumber, or logging company person traveling or wishing to travel abroad, or overseas travel agent trucking company, or motor carrier television station union member unemployed person or unemployment compensation applicant or claimant union, labor organization, or official of veteran voter, prospective voter, elector, or a nonelective official seeking reapportionment or redistricting of legislative districts (POL) wholesale trade wife, or ex-wife witness, or person under subpoena network slave slave-owner bank of the united states timber company u.s. job applicants or employees Army and Air Force Exchange Service Atomic Energy Commission Secretary or administrative unit or personnel of the U.S. Air Force Department or Secretary of Agriculture Alien Property Custodian Secretary or administrative unit or personnel of the U.S. Army Board of Immigration Appeals Bureau of Indian Affairs Bonneville Power Administration Benefits Review Board Civil Aeronautics Board Bureau of the Census Central Intelligence Agency Commodity Futures Trading Commission Department or Secretary of Commerce Comptroller of Currency Consumer Product Safety Commission Civil Rights Commission Civil Service Commission, U.S. Customs Service or Commissioner of Customs Defense Base Closure and REalignment Commission Drug Enforcement Agency Department or Secretary of Defense (and Department or Secretary of War) Department or Secretary of Energy Department or Secretary of the Interior Department of Justice or Attorney General Department or Secretary of State Department or Secretary of Transportation Department or Secretary of Education U.S. Employees' Compensation Commission, or Commissioner Equal Employment Opportunity Commission Environmental Protection Agency or Administrator Federal Aviation Agency or Administration Federal Bureau of Investigation or Director Federal Bureau of Prisons Farm Credit Administration Federal Communications Commission (including a predecessor, Federal Radio Commission) Federal Credit Union Administration Food and Drug Administration Federal Deposit Insurance Corporation Federal Energy Administration Federal Election Commission Federal Energy Regulatory Commission Federal Housing Administration Federal Home Loan Bank Board Federal Labor Relations Authority Federal Maritime Board Federal Maritime Commission Farmers Home Administration Federal Parole Board Federal Power Commission Federal Railroad Administration Federal Reserve Board of Governors Federal Reserve System Federal Savings and Loan Insurance Corporation Federal Trade Commission Federal Works Administration, or Administrator General Accounting Office Comptroller General General Services Administration Department or Secretary of Health, Education and Welfare Department or Secretary of Health and Human Services Department or Secretary of Housing and Urban Development Interstate Commerce Commission Indian Claims Commission Immigration and Naturalization Service, or Director of, or District Director of, or Immigration and Naturalization Enforcement Internal Revenue Service, Collector, Commissioner, or District Director of Information Security Oversight Office Department or Secretary of Labor Loyalty Review Board Legal Services Corporation Merit Systems Protection Board Multistate Tax Commission National Aeronautics and Space Administration Secretary or administrative unit of the U.S. Navy National Credit Union Administration National Endowment for the Arts National Enforcement Commission National Highway Traffic Safety Administration National Labor Relations Board, or regional office or officer National Mediation Board National Railroad Adjustment Board Nuclear Regulatory Commission National Security Agency Office of Economic Opportunity Office of Management and Budget Office of Price Administration, or Price Administrator Office of Personnel Management Occupational Safety and Health Administration Occupational Safety and Health Review Commission Office of Workers' Compensation Programs Patent Office, or Commissioner of, or Board of Appeals of Pay Board (established under the Economic Stabilization Act of 1970) Pension Benefit Guaranty Corporation U.S. Public Health Service Postal Rate Commission Provider Reimbursement Review Board Renegotiation Board Railroad Adjustment Board Railroad Retirement Board Subversive Activities Control Board Small Business Administration Securities and Exchange Commission Social Security Administration or Commissioner Selective Service System Department or Secretary of the Treasury Tennessee Valley Authority United States Forest Service United States Parole Commission Postal Service and Post Office, or Postmaster General, or Postmaster United States Sentencing Commission Veterans' Administration War Production Board Wage Stabilization Board General Land Office of Commissioners Transportation Security Administration Surface Transportation Board U.S. Shipping Board Emergency Fleet Corp. Reconstruction Finance Corp. Department or Secretary of Homeland Security Unidentifiable International Entity