opinion: UNITED STATES v. SALERNO et al.
  No. 86-87.
  Argued January 21, 1987
  Decided May 26, 1987
  Rehnquist, C. J., delivered the opinion of the Court, in which White, Blackmun, Powell, O’Connor, and Scalia, JJ., joined. Marshall, J., filed a dissenting opinion, in which Brennan, J., joined, post, p. 755. Stevens, J., filed a dissenting opinion, post, p. 767.
  Solicitor General Fried argued the cause for the United States. With him on the briefs were Assistant Attorney General Weld, Deputy Solicitor General Bryson, Jeffrey P. Minear, Samuel Rosenthal, and Maury S. Epner.
  Anthony M. Cardinale argued the cause for respondents. With him on the brief was Kimberly Homan
  Briefs of amici curiae urging affirmance were filed for the National Association of Criminal Defense Lawyers by Jon May and Mark King Leban; and for the Public Defender Service by Cheryl M. Long, James Klein, and David A. Reiser.
  Briefs of amici curiae were filed for the American Bar Association by Eugene C. Thomas, Charles G. Cole, and David A. Schlueter; for the American Civil Liberties Union et al. by William J. Genego, Dennis E. Curtis, Mark Rosenbaum, Paul Hoffman, Richard Emery, Martin Guggenheim, Alvin Bronstein, and David Goldstein; and for Howard Perry by Allen N. Brunwasser.
  Chief Justice Rehnquist
  delivered the opinion of the Court.
  The Bail Reform Act of 1984 (Act) allows a federal court to detain an arrestee pending trial if the Government demonstrates by clear and convincing evidence after an adversary hearing that no release conditions “will reasonably assure . . . the safety of any other person and the community.” The United States Court of Appeals for the Second Circuit struck down this provision of the Act as facially unconstitutional, because, in that court’s words, this type of pretrial detention violates “substantive due process.” We granted certiorari because of a conflict among the Courts of Appeals regarding the validity of the Act. 479 U. S. 929 (1986). We hold that, as against the facial attack mounted by these respondents, the Act fully comports with constitutional requirements. We therefore reverse.
  r — 4
  Responding to “the alarming problem of crimes committed by persons on release,” S. Rep. No. 98-225, p. 3 (1983), Congress formulated the Bail Reform Act of 1984, 18 U. S. C. §3141 et seq. (1982 ed., Supp. III), as the solution to a bail crisis in the federal courts. The Act represents the National Legislature’s considered response to numerous perceived deficiencies in the federal bail process. By providing for sweeping changes in both the way federal courts consider bail applications and the circumstances under which bail is granted, Congress hoped to “give the courts adequate authority to make release decisions that give appropriate recognition to the danger a person may pose to others if released.” S. Rep. No. 98-225, at 3.
  To this end, § 3141(a) of the Act requires a judicial officer to determine whether an arrestee shall be detained. Section 3142(e) provides that “[i]f, after a hearing pursuant to the provisions of subsection (f), the judicial officer finds that no condition or combination of conditions will reasonably assure the appearance of the person as required and the safety of any other person and the community, he shall order the detention of the person prior to trial.” Section 3142(f) provides the arrestee with a number of procedural safeguards. He may request the presence of counsel at the detention hearing, he may testify and present witnesses in his behalf, as well as proffer evidence, and he may cross-examine other witnesses appearing at the hearing. If the judicial officer finds that no conditions of pretrial release can reasonably assure the safety of other persons and the community, he must state his findings of fact in writing, § 3142(i), and support his conclusion with “clear and convincing evidence,” § 3142(f).
  The judicial officer is not given unbridled discretion in making the detention determination. Congress has specified the considerations relevant to that decision. These factors include the nature and seriousness of the charges, the substan-tiality of the Government’s evidence against the arrestee, the arrestee’s background and characteristics, and the nature and seriousness of the danger posed by the suspect’s release. § 3142(g). Should a judicial officer order detention, the detainee is entitled to expedited appellate review of the detention order. §§ 3145(b), (c).
  Respondents Anthony Salerno and Vincent Cafaro were arrested on March 21,1986, after being charged in a 29-count indictment alleging various Racketeer Influenced and Corrupt Organizations Act (RICO) violations, mail and wire fraud offenses, extortion, and various criminal gambling violations. The RICO counts alleged 35 acts of racketeering activity, including fraud, extortion, gambling, and conspiracy to commit murder. At respondents’ arraignment, the Government moved to have Salerno and Cafaro detained pursuant to § 3142(e), on the ground that no condition of release would assure the safety of the community or any person. The District Court held a hearing at which the Government made a detailed proffer of evidence. The Government’s case showed that Salerno was the “boss” of the Genovese crime family of La Cosa Nostra and that Cafaro was a “captain” in the Genovese family. According to the Government’s proffer, based in large part on conversations intercepted by a court-ordered wiretap, the two respondents had participated in wide-ranging conspiracies to aid their illegitimate enterprises through violent means. The Government also offered the testimony of two of its trial witnesses, who would assert that Salerno personally participated in two murder conspiracies. Salerno opposed the motion for detention, challenging the credibility of the Government’s witnesses. He offered the testimony of several character witnesses as well as a letter from his doctor stating that he was suffering from a serious medical condition. Cafaro presented no evidence at the hearing, but instead characterized the wiretap conversations as merely “tough talk.”
  The District Court granted the Government’s detention motion, concluding that the Government had established by clear and convincing evidence that no condition or combination of conditions of release would ensure the safety of the community or any person:
  “The activities of a criminal organization such as the Genovese Family do not cease with the arrest of its principals and their release on even the most stringent of bail conditions. The illegal businesses, in place for many years, require constant attention and protection, or they will fail. Under these circumstances, this court recognizes a strong incentive on the part of its leadership to continue business as usual. When business as usual involves threats, beatings, and murder, the present danger such people pose in the community is self-evident.” 631 F. Supp. 1364, 1375 (SDNY 1986).
  Respondents appealed, contending that to the extent that the Bail Reform Act permits pretrial detention on the ground that the arrestee is likely to commit future crimes, it is unconstitutional on its face. Over a dissent, the United States Court of Appeals for the Second Circuit agreed. 794 F. 2d 64 (1986). Although the court agreed that pretrial detention could be imposed if the defendants were likely to intimidate witnesses or otherwise jeopardize the trial process, it found “§ 3142(e)’s authorization of pretrial detention [on the ground of future dangerousness] repugnant to the concept of substantive due process, which we believe prohibits the total deprivation of liberty simply as a means of preventing future crimes.” Id., at 71-72. The court concluded that the Government could not, consistent with due process, detain persons who had not been accused of any crime merely because they were thought to present a danger to the community. Id., at 72, quoting United States v. Melendez-Carrion, 790 F. 2d 984, 1000-1001 (CA2 1986) (opinion of Newman, J.). It reasoned that our criminal law system holds persons accountable for past actions, not anticipated future actions. Although a court could detain an arrestee who threatened to flee before trial, such detention would be permissible because it would serve the basic objective of a criminal system— bringing the accused to trial. The court distinguished our decision in Gerstein v. Pugh, 420 U. S. 103 (1975), in which we upheld police detention pursuant to arrest. The court construed Gerstein as limiting such detention to the “ ‘administrative steps incident to arrest.’ ” 794 F. 2d, at 74, quoting Gerstein, supra, at 114. The Court of Appeals also found our decision in Schall v. Martin, 467 U. S. 253 (1984), upholding postarrest, pretrial detention of juveniles, inapposite because juveniles have a lesser interest in liberty than do adults. The dissenting judge concluded that on its face, the Bail Reform Act adequately balanced the Federal Government’s compelling interests in public safety against the detainee’s liberty interests.
  II
  A facial challenge to a legislative Act is, of course, the most difficult challenge to mount successfully, since the challenger must establish that no set of circumstances exists under which the Act would be valid. The fact that the Bail Reform Act might operate unconstitutionally under some conceivable set of circumstances is insufficient to render it wholly invalid, since we have not recognized an “overbreadth” doctrine outside the limited context of the First Amendment. Schall v. Martin, supra, at 269, n. 18. We think respondents have failed to shoulder their heavy burden to demonstrate that the Act is “facially” unconstitutional.
  Respondents present two grounds for invalidating the Bail Reform Act’s provisions permitting pretrial detention on the basis of future dangerousness. First, they rely upon the Court of Appeals’ conclusion that the Act exceeds the limitations placed upon the Federal Government by the Due Process Clause of the Fifth Amendment. Second, they contend that the Act contravenes the Eighth Amendment’s proscription, against excessive bail. We treat these contentions in turn.
  A
  The Due Process Clause of the Fifth Amendment provides that “No person shall... be deprived of life, liberty, or property, without due process of law . . . .” This Court has held that the Due Process Clause protects individuals against two types of government action. So-called “substantive due process” prevents the government from engaging in conduct that “shocks the conscience,” Rochin v. California, 342 U. S. 165, 172 (1952), or interferes with rights “implicit in the concept of ordered liberty,” Palko v. Connecticut, 302 U. S. 319, 325-326 (1937). When government action depriving a person of life, liberty, or property survives substantive due process scrutiny, it must still be implemented in a fair manner. Mathews v. Eldridge, 424 U. S. 319, 335 (1976). This requirement has traditionally been referred to as “procedural” due process.
  Respondents first argue that the Act violates substantive due process because the pretrial detention it authorizes constitutes impermissible punishment before trial. See Bell v. Wolfish, 441 U. S. 520, 535, and n. 16 (1979). The Government, however, has never argued that pretrial detention could be upheld if it were “punishment.” The Court of Appeals assumed that pretrial detention under the Bail Reform Act is regulatory, not penal, and we agree that it is.
  As an initial matter, the mere fact that a person is detained does not inexorably lead to the conclusion that the government has imposed punishment. Bell v. Wolfish, supra, at 537. To determine whether a restriction on liberty constitutes impermissible punishment or permissible regulation, we first look to legislative intent. Schall v. Martin, 467 U. S., at 269. Unless Congress expressly intended to impose punitive restrictions, the punitive/regulatory distinction turns on “‘whether an alternative purpose to which [the restriction] may rationally be connected is assignable for it, and whether it appears excessive in relation to the alternative purpose assigned [to it].’” Ibid., quoting Kennedy v. Mendoza-Martinez, 372 U. S. 144, 168-169 (1963).
  We conclude that the detention imposed by the Act falls on the regulatory side of the dichotomy. The legislative history of the Bail Reform Act clearly indicates that Congress did not formulate the pretrial detention provisions as punishment for dangerous individuals. See S. Rep. No. 98-225, at 8. Congress instead perceived pretrial detention as a potential solution to a pressing societal problem. Id., at 4-7. There is no doubt that preventing danger to the community is a legitimate regulatory goal. Schall v. Martin, supra.
  Nor are the incidents of pretrial detention excessive in relation to the regulatory goal Congress sought to achieve. The Bail Reform Act carefully limits the circumstances under which detention may be sought to the most serious of crimes. See 18 U. S. C. § 3142(f) (detention hearings available if case involves crimes of violence, offenses for which the sentence is life imprisonment or death, serious drug offenses, or certain repeat offenders). The arrestee is entitled to a prompt detention hearing, ibid., and the maximum length of pretrial detention is limited by the stringent time limitations of the Speedy Trial Act. See 18 U. S. C. §3161 et seq. (1982 ed. and Supp. III). Moreover, as in Schall v. Martin, the conditions of confinement envisioned by the Act “appear to reflect the regulatory purposes relied upon by the” Government. 467 U. S., at 270. As in Schall, the statute at issue here requires that detainees be housed in a “facility separate, to the extent practicable, from persons awaiting or serving sentences or being held in custody pending appeal.” 18 U. S. C. § 3142(i)(2). We conclude, therefore, that the pretrial detention contemplated by the Bail Reform Act is regulatory in nature, and does not constitute punishment before trial in violation of the Due Process Clause.
  The Court of Appeals nevertheless concluded that “the Due Process Clause prohibits pretrial detention on the ground of danger to the community as a regulatory measure, without regard to the duration of the detention.” 794 F. 2d, at 71. Respondents characterize the Due Process Clause as erecting an impenetrable “wall” in this area that “no governmental interest — rational, important, compelling or otherwise — may surmount.” Brief for Respondents 16.
  We do not think the Clause lays down any such categorical imperative. We have repeatedly held that the Government’s regulatory interest in community safety can, in appropriate circumstances, outweigh an individual’s liberty interest. For example, in times of war or insurrection, when society’s interest is at its peak, the Government may detain individuals whom the Government believes to be dangerous. See Ludecke v. Watkins, 335 U. S. 160 (1948) (approving un-reviewable executive power to detain enemy aliens in time of war); Moyer v. Peabody, 212 U. S. 78, 84-85 (1909) (rejecting due process claim of individual jailed without probable cause by Governor in time of insurrection). Even outside the exigencies of war, we have found that sufficiently compelling governmental interests can justify detention of dangerous persons. Thus, we have found no absolute constitutional barrier to detention of potentially dangerous resident aliens pending deportation proceedings. Carlson v. Landon, 342 U. S. 524, 537-542 (1952); Wong Wing v. United States, 163 U. S. 228 (1896). We have also held that the government may detain mentally unstable individuals who present a danger to the public, Addington v. Texas, 441 U. S. 418 (1979), and dangerous defendants who become incompetent to stand trial, Jackson v. Indiana, 406 U. S. 715, 731-739 (1972); Greenwood v. United States, 350 U. S. 366 (1956). We have approved of postarrest regulatory detention of juveniles when they present a continuing danger to the community. Schall v. Martin, supra. Even competent adults may face substantial liberty restrictions as a result of the operation of our criminal justice system. If the police suspect an individual of a crime, they may arrest and hold him until a neutral magistrate determines whether probable cause exists. Gerstein v. Pugh, 420 U. S. 103 (1975). Finally, respondents concede and the Court of Appeals noted that an arrestee may be incarcerated until trial if he presents a risk of flight, see Bell v. Wolfish, 441 U. S., at 534, or a danger to witnesses.
  Respondents characterize all of these cases as exceptions to the “general rule” of substantive due process that the government may not detain a person prior to a judgment of guilt in a criminal trial. Such a “general rule” may freely be conceded, but we think that these cases show a sufficient number of exceptions to the rule that the congressional action challenged here can hardly be characterized as totally novel. Given the well-established authority of the government, in special circumstances, to restrain individuals’ liberty prior to or even without criminal trial and conviction, we think that the present statute providing for pretrial detention on the basis of dangerousness must be evaluated in precisely the same manner that we evaluated the laws in the cases discussed above.
  The government’s interest in preventing crime by arrest-ees is both legitimate and compelling. De Veau v. Braisted, 363 U. S. 144, 155 (1960). In Schall, supra, we recognized the strength of the State’s interest in preventing juvenile crime. This general concern with crime prevention is no less compelling when the suspects are adults. Indeed, “[t]he harm suffered by the victim of a crime is not dependent upon the age of the perpetrator.” Schall v. Martin, supra, at 264-265. The Bail Reform Act of 1984 responds to an even more particularized governmental interest than the interest we sustained in Schall. The statute we upheld in Schall permitted pretrial detention of any juvenile arrested on any charge after a showing that the individual might commit some undefined further crimes. The Bail Reform Act, in contrast, narrowly focuses on a particularly acute problem in which the Government interests are overwhelming. The Act operates only on individuals who have been arrested for a specific category of extremely serious offenses. 18 U. S. C. § 3142(f). Congress specifically found that these individuals are far more likely to be responsible for dangerous acts in the community after arrest. See S. Rep. No. 98-225, at 6-7. Nor is the Act by any means a scattershot attempt to incapacitate those who are merely suspected of these serious crimes. The Government must first of all demonstrate probable cause to believe that the charged crime has been committed by the arrestee, but that is not enough. In a full-blown adversary hearing, the Government must convince a neutral decisionmaker by clear and convincing evidence that no conditions of release can reasonably assure the safety of the community or any person. 18 U. S. C. § 3142(f). While the Government’s general interest in preventing crime is compelling, even this interest is heightened when the Government musters convincing proof that the arrestee, already indicted or held to answer for a serious crime, presents a demonstrable danger to the community. Under these narrow circumstances, society’s interest in crime prevention is at its greatest.
  On the other side of the scale, of course, is the individual’s strong interest in liberty. We do not minimize the importance and fundamental nature of this right. But, as our cases hold, this right may, in circumstances where the government’s interest is sufficiently weighty, be subordinated to the greater needs of society. We think that Congress’ careful delineation of the circumstances under which detention will be permitted satisfies this standard. When the Government proves by clear and convincing evidence that an arrestee presents an identified and articulable threat to an individual or the community, we believe that, consistent with the Due Process Clause, a court may disable the arrestee from executing that threat. Under these circumstances, we cannot categorically state that pretrial detention “offends some principle of justice so rooted in the traditions and conscience of our people as to be ranked as fundamental.” Snyder v. Massachusetts, 291 U. S. 97, 105 (1934).
  Finally, we may dispose briefly of respondents’ facial challenge to the procedures of the Bail Reform Act. To sustain them against such a challenge, we need only find them “adequate to authorize the pretrial detention of at least some [persons] charged with crimes,” Schall, supra, at 264, whether or not they might be insufficient in some particular circumstances. We think they pass that test. As we stated in Schall, “there is nothing inherently unattainable about a prediction of future criminal conduct.” 467 U. S., at 278; see Jurek v. Texas, 428 U. S. 262, 274 (1976) (joint opinion of Stewart, Powell, and Stevens, JJ.); id., at 279 (White, J., concurring in judgment).
  Under the Bail Reform Act, the procedures by which a judicial officer evaluates the likelihood of future dangerousness are specifically designed to further the accuracy of that determination. Detainees have a right to counsel at the detention hearing. 18 U. S. C. § 3142(f). They may testify in their own behalf, present information by proffer or otherwise, and cross-examine witnesses who appear at the hearing. Ibid. The judicial officer charged with the responsibility of determining the appropriateness of detention is guided by statutorily enumerated factors, which include the nature and the circumstances of the charges, the weight of the evidence, the history and characteristics of the putative offender, and the danger to the community. § 3142(g). The Government must prove its case by clear and convincing evidence. § 3142(f). Finally, the judicial officer must include written findings of fact and a written statement of reasons for a decision to detain. § 3142(i). The Act’s review provisions, § 3145(c), provide for immediate appellate review of the detention decision.
  We think these extensive safeguards suffice to repel a facial challenge. The protections are more exacting than those we found sufficient in the juvenile context, see Schall, supra, at 275-281, and they far exceed what we found necessary to effect limited postarrest detention in Gerstein v. Pugh, 420 U. S. 103 (1975). Given the legitimate and compelling regulatory purpose of the Act and the procedural protections it offers, we conclude that the Act is not facially invalid under the Due Process Clause of the Fifth Amendment.
  B
  Respondents also contend that the Bail Reform Act violates the Excessive Bail Clause of the Eighth Amendment. The Court of Appeals did not address this issue because it found that the Act violates the Due Process Clause. We think that the Act survives a challenge founded upon the Eighth Amendment.
  The Eighth Amendment addresses pretrial release by providing merely that “[ejxcessive bail shall not be required.” This Clause, of course, says nothing about whether bail shall be available at all. Respondents nevertheless contend that this Clause grants them a right to bail calculated solely upon considerations of flight. They rely on Stack v. Boyle, 342 U. S. 1, 5 (1951), in which the Court stated that “[bjail set at a figure higher than an amount reasonably calculated [to ensure the defendant’s presence at trial] is ‘excessive’ under the Eighth Amendment.” In respondents’ view, since the Bail Reform Act allows a court essentially to set bail at an infinite amount for reasons not related to the risk of flight, it violates the Excessive Bail Clause. Respondents concede that the right to bail they have discovered in the Eighth Amendment is not absolute. A court may, for example, refuse bail in capital cases. And, as the Court of Appeals noted and respondents admit, a court may refuse bail when the defendant presents a threat to the judicial process by intimidating witnesses. Brief for Respondents 21-22. Respondents characterize these exceptions as consistent with what they claim to be the sole purpose of bail — to ensure the integrity of the judicial process.
  While we agree that a primary function of bail is to safeguard the courts’ role in adjudicating the guilt or innocence of defendants, we reject the proposition that the Eighth Amendment categorically prohibits the government from pursuing other admittedly compelling interests through regulation of pretrial release. The above-quoted dictum in Stack v. Boyle is far too slender a reed on which to rest this argument. The Court in Stack had no occasion to consider whether the Excessive Bail Clause requires courts to admit all defendants to bail, because the statute before the Court in that case in fact allowed the defendants to be bailed. Thus, the Court had to determine only whether bail, admittedly available in that case, was excessive if set at a sum greater than that necessary to ensure the arrestees’ presence at trial.
  The holding of Stack is illuminated by the Court’s holding just four months later in Carlson v. Landon, 342 U. S. 524 (1952). In that case, remarkably similar to the present action, the detainees had been arrested and held without bail pending a determination of deportability. The Attorney General refused to release the individuals, “on the ground that there was reasonable cause to believe that [their] release would be prejudicial to the public interest and would endanger the welfare and safety of the United States.” Id., at 529 (emphasis added). The detainees brought the same challenge that respondents bring to us today: the Eighth Amendment required them to be admitted to bail. The Court squarely rejected this proposition:
  “The bail clause was lifted with slight changes from the English Bill of Rights Act. In England that clause has never been thought to accord a right to bail in all cases, but merely to provide that bail shall not be excessive in those cases where it is proper to grant bail. When this clause was carried over into our Bill of Rights, nothing was said that indicated any different concept. The Eighth Amendment has not prevented Congress from defining the classes of cases in which bail shall be allowed in this country. Thus, in criminal cases bail is not compulsory where the punishment may be death. Indeed, the very language of the Amendment fails to say all arrests must be bailable.” Id., at 545-546 (footnotes omitted).
  Carlson v. Landon was a civil case, and we need not decide today whether the Excessive Bail Clause speaks at all to Congress’ power to define the classes of criminal arrestees who shall be admitted to bail. For even if we were to conclude that the Eighth Amendment imposes some substantive limitations on the National Legislature’s powers in this area, we would still hold that the Bail Reform Act is valid. Nothing in the text of the Bail Clause limits permissible Government considerations solely to questions of flight. The only arguable substantive limitation of the Bail Clause is that the Government’s proposed conditions of release or detention not be “excessive” in light of the perceived evil. Of course, to determine whether the Government’s response is excessive, we must compare that response against the interest the Government seeks to protect by means of that response. Thus, when the Government has admitted that its only interest is in preventing flight, bail must be set by a court at a sum designed to ensure that goal, and no more. Stack v. Boyle, supra. We believe that when Congress has mandated detention on the basis of a compelling interest other than prevention of flight, as it has here, the Eighth Amendment does not require release on bail.
  I — I I — I HH
  In our society liberty is the norm, and detention prior to trial or without trial is the carefully limited exception. We hold that the provisions for pretrial detention in the Bail Reform Act of 1984 fall within that carefully limited exception. The Act authorizes the detention prior to trial of arrestees charged with serious felonies who are found after an adversary hearing to pose a threat to the safety of individuals or to the community which no condition of release can dispel. The numerous procedural safeguards detailed above must attend this adversary hearing. We are unwilling to say that this congressional determination, based as it is upon that primary concern of every government — a concern for the safety and indeed the lives of its citizens — on its face violates either the Due Process Clause of the Fifth Amendment or the Excessive Bail Clause of the Eighth Amendment.
  The judgment of the Court of Appeals is therefore
  Reversed.
  Every other Court of Appeals to have considered the validity of the Bail Reform Act of 1984 has rejected the facial constitutional challenge. United States v. Walker, 805 F. 2d 1042 (CA11 1986); United States v. Rodriguez, 803 F. 2d 1102 (CA11 1986); United States v. Simpkins, 255 U. S. App. D. C. 306, 801 F. 2d 520 (1986); United States v. Zannino, 798 F. 2d 544 (CA1 1983); United States v. Perry, 788 F. 2d 100 (CA3), cert. denied, 479 U. S. 864 (1986); United States v. Portes, 786 F. 2d 758 (CA7 1985).
  Salerno was subsequently sentenced in unrelated proceedings before a different judge. To this date, however, Salerno has not been confined pursuant to that sentence. The authority for Salerno’s present incarceration remains the District Court’s pretrial detention order. The case is therefore very much alive and is properly presented for our resolution.
  We intimate no view on the validity of any aspects of the Act that are not relevant to respondents’ case. Nor have respondents claimed that the Act is unconstitutional because of the way it was applied to the particular facts of their case.
  We intimate no view as to the point at which detention in a particular case might become excessively prolonged, and therefore punitive, in relation to Congress’ regulatory goal.