opinion: MITCHELL v. FORSYTH
  No. 84-335.
  Argued February 27, 1985
  Decided June 19, 1985
  White, J., delivered the opinion of the Court, in which Blackmun, J., joined; in Parts I, III, and IV of which Burger, C. J., and O’Connor, J., joined; and in Parts I and II of which Brennan and Marshall, JJ., joined. Burger, C. J., filed an opinion concurring in part, post, p. 536. O’Connor, J., filed an opinion concurring in part, in which Burger, C. J., joined, post, p. 537. Stevens, J., filed an opinion concurring in the judgment, post, p. 538. Brennan, J., filed an opinion concurring in part and aissenting in part, in which Marshall, J., joined, post, p. 543. Powell, J., took no part in the decision of the case. Rehnqutst, J., took no part in the consideration or decision of the case.
  Deputy Solicitor General Bator argued the cause for petitioner. With him on the briefs were Solicitor General Lee, Acting Assistant Attorney General Willard, Samuel A. Alito, Jr., Barbara L. Herwig, Gorden W. Daiger, and Larry L. Gregg.
  David Rudovsky argued the cause for respondent. With him on the brief was Michael Avery.
  Justice White
  delivered the opinion of the Court.
  This is a suit for damages stemming from a warrantless wiretap authorized by petitioner, a former Attorney General of the United States. The case presents three issues: whether the Attorney General is absolutely immune from suit for actions undertaken in the interest of national security; if not, whether the District Court’s finding that petitioner is not immune from suit for his actions under the qualified immunity standard of Harlow v. Fitzgerald, 457 U. S. 800 (1982), is appealable; and, if so, whether the District Court’s ruling on qualified immunity was correct.
  H
  In 1970, the Federal Bureau of Investigation learned that members of an antiwar group known as the East Coast Conspiracy to Save Lives (ECCSL) had made plans to blow up heating tunnels linking federal office buildings in Washington, D. C., and had also discussed the possibility of kidnaping then National Security Adviser Henry Kissinger. On November 6, 1970, acting on the basis of this information, the then Attorney General John Mitchell authorized a war-rantless wiretap on the telephone of William Davidon, a Haverford College physics professor who was a member of the group. According to the Attorney General, the purpose of the wiretap was the gathering of intelligence in the interest of national security.
  The FBI installed the tap in late November 1970, and it stayed in place until January 6, 1971. During that time, the Government intercepted three conversations between Davidon and respondent Keith Forsyth. The record before us does not suggest that the intercepted conversations, which appear to be innocuous, were ever used against Forsyth in any way. Forsyth learned of the wiretap in 1972, when, as a criminal defendant facing unrelated charges, he moved under 18 U. S. C. § 3504 for disclosure by the Government of any electronic surveillance to which he had been subjected. The Government's response to Forsyth's motion revealed that although he had never been the actual target of electronic surveillance, he “did participate in conversations that are unrelated to this case and which were overheard by the Federal Government during the course of electronic surveillance expressly authorized by the President acting through the Attorney General.” App. 20-21. The Government's response was accompanied by an affidavit, sworn to by then Attorney General Richard Kleindienst, averring that the surveillance to which Forsyth had been subjected was authorized “in the exercise of [the President’s] authority relating to the national security as set forth in 18 U. S. C. 2511(3).” Id., at 23.
  Shortly thereafter, this Court ruled that the Fourth Amendment does not permit the use of warrantless wiretaps in cases involving domestic threats to the national security. United States v. United States District Court, 407 U. S. 297 (1972) (Keith). In the wake of the Keith decision, For-syth filed this lawsuit against John Mitchell and several other defendants in the United States District Court for the Eastern District of Pennsylvania. Forsyth alleged that the surveillance to which he had been subjected violated both the Fourth Amendment and Title III of the Omnibus Crime Control and Safe Streets Act of 1968, 18 U. S. C. §§2510-2520, which sets forth comprehensive standards governing the use of wiretaps and electronic surveillance by both governmental and private agents. He asserted that both the constitutional and statutory provisions provided him with a private right of action; he sought compensatory, statutory, and punitive damages.
  Discovery and related preliminary proceedings dragged on for the next five-and-a-half years. By early 1978, both Forsyth and Mitchell had submitted motions for summary judgment on which the District Court was prepared to rule. Forsyth contended that the uncontested facts established that the wiretap was illegal and that Mitchell and the other defendants were not immune from liability; Mitchell contended that the decision in Keith should not be applied retroactively to the wiretap authorized in 1970 and that he was entitled either to absolute prosecutorial immunity from suit under the rule of Imbler v. Pachtman, 424 U. S. 409 (1976), or to qualified or “good faith” immunity under the doctrine of Wood v. Strickland, 420 U. S. 308 (1975).
  The court found that there was no genuine dispute as to the facts that the FBI had informed Mitchell of the ECCSL’s plots, that Mitchell had authorized the warrantless tap on Davidon’s phone, and that the ostensible purpose of the tap was the gathering of intelligence in the interest of national security. Such a wiretap, the court concluded, was a clear violation of the Fourth Amendment under Keith, which, in the court’s view, was to be given retroactive effect. The court also rejected Mitchell’s claim to absolute immunity from suit under Imbler v. Pachtman: Imbler, the court held, provided absolute immunity to a prosecutor only for his acts in “initiating and pursuing a criminal prosecution”; Mitchell’s authorization of the wiretap constituted the performance of an investigative rather than prosecutorial function. Forsyth v. Kleindienst, 447 F. Supp. 192, 201 (1978). Although rejecting Mitchell’s claim of absolute immunity, the court found that Mitchell was entitled to assert a qualified immunity from suit and could prevail if he proved that he acted in good faith. Applying this standard, with its focus on Mitchell’s state of mind at the time he authorized the wiretap, the court concluded that neither side had met its burden of establishing that there was no genuine issue of material fact as to Mitchell’s good faith. Accordingly, the court denied both parties’ motions for summary judgment. Id., at 203.
  Mitchell appealed the District Court’s denial of absolute immunity to the United States Court of Appeals for the Third Circuit, which remanded for further factfinding on the question whether the wiretap authorization was “necessary to [a] . . . decision to initiate a criminal prosecution” and thus within the scope of the absolute immunity recognized in Imbler v. Pachtman. Forsyth v. Kleindienst, 599 F. 2d 1203, 1217 (1979). On remand, the District Court held a hearing on the question whether the wiretap served a pros-ecutorial purpose. On the basis of the hearing and the evidence in the record, the court concluded that Mitchell’s authorization of the wiretap was not intended to facilitate any prosecutorial decision or further a criminal investigation. Mitchell himself had disavowed any such intention and insisted that the only reason for the wiretap was to gather intelligence needed for national security purposes. Taking Mitchell at his word in this regard, the court held to its conclusion that he was not entitled to absolute prosecutorial immunity.
  At the same time, the court reconsidered its ruling on qualified immunity in light of Harlow v. Fitzgerald, 457 U. S. 800 (1982), in which this Court purged qualified immunity doctrine of its subjective components and held that “government officials performing discretionary functions, generally are shielded from liability for civil damages insofar as their conduct does not violate clearly established statutory or constitutional rights of which a reasonable person would have known.” Id., at 818. The District Court rejected Mitchell’s argument that under this standard he should be held immune from suit for warrantless national security wiretaps authorized before this Court’s decision in Keith: that decision was merely a logical extension of general Fourth Amendment principles and in particular of the ruling in Katz v. United States, 389 U. S. 347 (1967), in which the Court held for the first time that electronic surveillance unaccompanied by physical trespass constituted a search subject to the Fourth Amendment’s warrant requirement. Mitchell and the Justice Department, the court suggested, had chosen to “gamble” on the possibility that this Court would create an exception to the warrant' requirement if presented with a case involving national security. Having lost the gamble, Mitchell was not entitled to complain of the consequences. The court therefore denied Mitchell’s motion for summary judgment, granted Forsyth’s motion for summary judgment on the issue of liability, and scheduled further proceedings on the issue of damages. Forsyth v. Kleindienst, 551 F. Supp. 1247 (1982).
  Mitchell again appealed, contending that the District Court had erred in its rulings on both absolute immunity and qualified immunity. Holding that it possessed jurisdiction to decide the denial of absolute immunity issue despite the fact that it was a pretrial order and arguably not a final judgment, the Court of Appeals rejected Mitchell’s argument that the national security functions of the Attorney General entitled him to absolute immunity under Imbler v. Pachtman or otherwise. With respect to the denial of qualified immunity, the Court of Appeals held that the District Court’s order was not appealable under the collateral order doctrine of Cohen v. Beneficial Industrial Loan Corp., 337 U. S. 541 (1949). Fearing that allowing piecemeal appeals of such issues would unduly burden appellate courts, the court was unwilling to hold that the goal of protecting officials against frivolous litigation required that orders denying qualified immunity be immediately appealable. Forsyth’s claim, the court noted, was not a frivolous one, and the policies underlying the immunity doctrine would therefore not be frustrated if Mitchell were forced to wait until final judgment to appeal the qualified immunity ruling. Forsyth v. Kleindienst, 729 F. 2d 267 (1984). The court therefore remanded the case to the District Court for further proceedings leading to the entry of final judgment, and Mitchell filed a timely petition for certiorari seeking review of the court’s rulings on both absolute and qualified immunity.
  The question whether the Attorney General is absolutely immune from suit for acts performed in the exercise of his national security functions is an important one that we have hitherto left unanswered. See Halperin v. Kissinger, 196 U. S. App. D. C., 285, 606 F. 2d 1192 (1979), aff’d by an equally divided Court, 452 U. S. 713 (1981). Moreover, the issue of the appealability before final judgment of orders denying immunity under the objective standard of Harlow v. Fitzgerald is one that has divided the Courts of Appeals. Finally, the District Court’s decision — left standing by the Court of Appeals — that Mitchell’s actions violated clearly established law is contrary to the rulings of the District of Columbia Circuit in Sinclair v. Kleindienst, 207 U. S. App. D. C. 155, 645 F. 2d 1080 (1981), and Zweibon v. Mitchell, 231 U. S. App. D. C. 398, 720 F. 2d 162 (1983), cert. denied, 469 U. S. 880 (1984). We granted certiorari to address these issues, 469 U. S. 929 (1984).
  HH ) — I
  We first address Mitchell’s claim that the Attorney General’s actions in furtherance of the national security should be shielded from scrutiny in civil damages actions by an absolute immunity similar to that afforded the President, see Nixon v. Fitzgerald, 457 U. S. 731 (1982), judges, prosecutors, witnesses, and officials performing “quasi-judicial” functions, see Briscoe v. LaHue, 460 U. S. 325 (1983); Butz v. Economou, 438 U. S. 478, 508-517 (1978); Stump v. Sparkman, 435 U. S. 349 (1978); Imbler v. Pachtman, 424 U. S. 409 (1976), and legislators, see Dombrowski v. Eastland, 387 U. S. 82 (1967); Tenney v. Brandhove, 341 U. S. 367 (1951). We conclude that the Attorney General is not absolutely immune from suit for damages arising out of his allegedly unconstitutional conduct in performing his national security functions.
  As the Nation’s chief law enforcement officer, the Attorney General provides vital assistance to the President in the performance of the latter’s constitutional duty to “preserve, protect, and defend the Constitution of the United States.” U. S. Const., Art. II, §1, cl. 8. Mitchell’s argument, in essence, is that the national security functions of the Attorney General are so sensitive, so vital to the protection of our Nation’s well-being, that we cannot tolerate any risk that in performing those functions he will be chilled by the possibility of personal liability for acts that may be found to impinge on the constitutional rights of citizens. Such arguments, “when urged on behalf of the President and the national security in its domestic implications, merit the most careful consideration.” Keith, 407 U. S., at 319. Nonetheless, we do not believe that the considerations that have led us to recognize absolute immunities for other officials dictate the same result in this case.
  Our decisions in this area leave no doubt that the Attorney General’s status as a Cabinet officer is not in itself sufficient to invest him with absolute immunity: the considerations of separation of powers that call for absolute immunity for state and federal legislators and for the President of the United States do not demand a similar immunity for Cabinet officers or other high executive officials. See Harlow v. Fitzgerald, 457 U. S. 800 (1982); Butz v. Economou, supra. Mitchell’s claim, then, must rest not on the Attorney General’s position within the Executive Branch, but on the nature of the functions he was performing in this case. See Harlow v. Fitzgerald, supra, at 810-811. Because Mitchell was not acting in a prosecutorial capacity in this case, the situations in which we have applied a functional approach to absolute immunity questions provide scant support for blanket immunization of his performance of the “national security function.”
  First, in deciding whether officials performing a particular function are entitled to absolute immunity, we have generally looked for a historical or common-law basis for the immunity in question. The legislative immunity recognized in Tenney v. Brandhove, supra, for example, was rooted in the long struggle in both England and America for legislative independence, a presupposition of our scheme of representative government. The immunities for judges, prosecutors, and witnesses established by our cases have firm roots in the common law. See Briscoe v. LaHue, supra, at 330-336. Mitchell points to no analogous historical or common-law basis for an absolute immunity for officers carrying out tasks essential to national security.
  Second, the performance of national security functions does not subject an official to the same obvious risks of entanglement in vexatious litigation as does the carrying out of the judicial or “quasi-judicial” tasks that have been the primary wellsprings of absolute immunities. The judicial process is an arena of open conflict, and in virtually every case there is, if not always a winner, at least one loser. It is inevitable that many of those who lose will pin the blame on judges, prosecutors, or witnesses and will bring suit against them in an effort to relitigate the underlying conflict. See Bradley v. Fisher, 13 Wall. 335, 348 (1872). National security tasks, by contrast, are carried out in secret; open conflict and overt winners and losers are rare. Under such circumstances, it is far more likely that actual abuses will go uncovered than that fancied abuses will give rise to unfounded and burdensome litigation. Whereas the mere threat of litigation may significantly affect the fearless and independent performance of duty by actors in the judicial process, it is unlikely to have a similar effect on the Attorney General’s performance of his national security tasks.
  Third, most of the officials who are entitled to absolute immunity from liability for damages are subject to other checks that help to prevent abuses of authority from going unre-dressed. Legislators are accountable to their constituents, see Tenney v. Brandhove, supra, at 378, and the judicial process is largely self-correcting: procedural rules, appeals, and the possibility of collateral challenges obviate the need for damages actions to prevent unjust results. Similar built-in restraints on the Attorney General’s activities in the name of national security, however, do not exist. And despite our recognition of the importance of those activities to the safety of our Nation and its democratic system of government, we cannot accept the notion that restraints are completely unnecessary. As the Court observed in Keith, the label of “national security” may cover a multitude of sins:
  “National security cases . . . often reflect a convergence of First and Fourth Amendment values not present in cases of ‘ordinary’ crime. Though the investigative duty of the executive may be stronger in such cases, so also is there greater jeopardy to constitutionally protected speech. . . . History abundantly documents the tendency of Government — however, benevolent and benign its motives — to view with suspicion those who most fervently dispute its policies. . . . The danger to political dissent is acute where the Government attempts to act under so vague a concept as the power to protect ‘domestic security.’ Given the difficulty of defining the domestic security interest, the danger of abuse in acting to protect that interest becomes apparent.” 407 U. S., at 313-314.
  The danger that high federal officials will disregard constitutional rights in their zeal to protect the national security is sufficiently real to counsel against affording such officials an absolute immunity.
  We emphasize that the denial of absolute immunity will not leave the Attorney General at the mercy of litigants with frivolous and vexatious complaints. Under the standard of qualified immunity articulated in Harlow v. Fitzgerald, the Attorney General will be entitled to immunity so long as his actions do not violate “clearly established statutory or constitutional rights of which a reasonable person would have known.” 457 U. S., at 818. This standard will not allow the Attorney General to carry out his national security functions wholly free from concern for his personal liability; he may on occasion have to pause to consider whether a proposed course of action can be squared with the Constitution and laws of the United States. But this is precisely the point of the Harlow standard: “Where an official could be expected to know that his conduct would violate statutory or constitutional rights, he should be made to hesitate . . . .” Id., at 819 (emphasis added). This is as true in matters of national security as in other fields of governmental action. We do not believe that the security of the Republic will be threatened if its Attorney General is given incentives to abide by clearly established law.
  Ill
  Although 28 U. S. C. §1291 vests the courts of appeals with jurisdiction over appeals only from “final decisions” of the district courts, “a decision ‘final’ within the meaning of § 1291 does not necessarily mean the last order possible to be made in a case.” Gillespie v. United States Steel Corp., 379 U. S. 148, 152 (1964). Thus, a decision of a district court is appealable if it falls within “that small class which finally determine claims of right separable from, and collateral to, rights asserted in the action, too important to be denied review and too independent of the cause itself to require that appellate consideration be deferred until the whole case is adjudicated.” Cohen v. Beneficial Industrial Loan Corp., 337 U. S., at 546.
  A major characteristic of the denial or granting of a claim appealable under Cohen’s “collateral order” doctrine is that “unless it can be reviewed before [the proceedings terminate], it never can be reviewed at all.” Stack v. Boyle, 342 U. S. 1, 12 (1952) (opinion of Jackson, J.); see also United States v. Hollywood Motor Car Co., 458 U. S. 263, 266 (1982). When a district court has denied a defendant’s claim of right not to stand trial, on double jeopardy grounds, for example, we have consistently held the court’s decision appealable, for such a right cannot be effectively vindicated after the trial has occurred. Abney v. United States, 431 U. S. 651 (1977). Thus, the denial of a substantial claim of absolute immunity is an order appealable before final judgment, for the essence of absolute immunity is its possessor’s entitlement not to have to answer for his conduct in a civil damages action. See Nixon v. Fitzgerald, 457 U. S. 731 (1982); cf. Helstoski v. Meanor, 442 U. S. 500 (1979).
  At the heart of the issue before us is the question whether qualified immunity shares this essential attribute of absolute immunity — whether qualified immunity is in fact an entitlement not to- stand trial under certain circumstances. The conception animating the qualified immunity doctrine as set forth in Harlow v. Fitzgerald, 457 U. S. 800 (1982), is that “where an official’s duties legitimately require action in which clearly established rights are not implicated, the public interest may be better served by action taken ‘with independence and without fear of consequences.’” Id., at 819, quoting Pierson v. Ray, 386 U. S. 547, 554 (1967). As the citation to Pierson v. Ray makes clear, the “consequences” with which we were concerned in Harlow are not limited to liability for money damages; they also include “the general costs of subjecting officials to the risks of trial — distraction of officials from their governmental duties, inhibition of discretionary action, and deterrence of able people from public service:” Harlow, 457 U. S., at 816. Indeed, Harlow emphasizes that even such pretrial matters as discovery are to be avoided if possible, as “[inquiries of this kind can be peculiarly disruptive of effective government.” Id., at 817.
  With these concerns in mind, the Harlow Court refashioned the qualified immunity doctrine in such a way as to “permit the resolution of many insubstantial claims on summary judgment” and to avoid “subjecting] government officials either to the costs of trial or to the burdens of broad-reaching discovery” in cases where the legal norms the officials are alleged to have violated were not clearly established at the time. Id., at 817-818. Unless the plaintiff’s allegations state a claim of violation of clearly established law, a defendant pleading qualified immunity is entitled to dismissal before the commencement of discovery. See id., at 818. Even if the plaintiff’s complaint adequately alleges the commission of acts that violated clearly established law, the defendant is entitled to summary judgment if discovery fails to uncover evidence sufficient to create a genuine issue as to whether the defendant in fact committed those acts. Harlow thus recognized an entitlement not to stand trial or face the other burdens of litigation, conditioned on the resolution of the essentially legal question whether the conduct of which the plaintiff complains violated clearly established law. The entitlement is an immunity from suit rather than a mere defense to liability; and like an absolute immunity, it is effectively lost if a case is erroneously permitted to go to trial. Accordingly, the reasoning that underlies the immediate appealability of an order denying absolute immunity indicates to us that the denial of qualified immunity should be similarly appealable: in each case, the district court’s decision is effectively unreviewable on appeal from a final judgment.
  An appealable interlocutory decision must satisfy two additional criteria: it must “conclusively determine the disputed question,” Coopers & Lybrand v. Livesay, 437 U. S. 463, 468 (1978), and that question must involve a “clai[m] of right separable from, and collateral to, rights asserted in the action,” Cohen, supra, at 546. The denial of a defendant’s motion for dismissal or summary judgment on the ground of qualified immunity easily meets these requirements. Such a decision is “conclusive” in either of two respects. In some cases, it may represent the trial court’s conclusion that even if the facts are as asserted by the defendant, the defendant’s actions violated clearly established law and are therefore not within the scope of the qualified immunity. In such a case, there will be nothing in the subsequent course of the proceedings in the district court that can alter the court’s conclusion that the defendant is not immune. Alternatively, the trial judge may rule only that if the facts are as asserted by the plaintiff, the defendant is not immune. At trial, the plaintiff may not succeed in proving.his version of the facts, and the defendant may thus escape liability. Even so, the court’s denial of summary judgment finally and conclusively determines the defendant’s claim of right not to stand trial on the plaintiff’s allegations, and because “[t]here are simply no further steps that can be taken in the District Court to avoid the trial the defendant maintains is barred,” it is apparent that “Cohen’s threshold requirement of a fully consummated decision is satisfied” in such a case. Abney v. United States, 431 U. S., at 659.
  Similarly, it follows from the recognition that qualified immunity is in part an entitlement not to be forced to litigate the consequences of official conduct that a claim of immunity is conceptually distinct from the merits of the plaintiff’s claim that his rights have been violated. See id., at 659-660. An appellate court reviewing the denial of the defendant’s claim of immunity need not consider the correctness of the plaintiff’s version of the facts, nor even determine whether the plaintiff’s allegations actually state a claim. All it need determine is a question of law: whether the legal norms allegedly violated by the defendant were clearly established at the time of the challenged actions or, in cases where the district court has denied summary judgment for the defendant on the ground that even under the defendant’s version of the facts the defendant’s conduct violated clearly established law, whether the law clearly proscribed the actions the defendant claims he took. To be sure, the resolution of these legal issues will entail consideration of the factual allegations that make up the plaintiff’s claim for relief; the same is true, however, when a court must consider whether a prosecution is barred by a claim of former jeopardy or whether a Congressman is absolutely immune from suit because the complained of conduct falls within the protections of the Speech and Debate Clause. In the case of a double jeopardy claim, the court must compare the facts alleged in the second indictment with those in the first to determine whether the prosecutions are for the same offense, while in evaluating a claim of immunity under the Speech and Debate Clause, a court must analyze the plaintiff’s complaint to determine whether the plaintiff seeks to hold a Congressman liable for protected legislative actions or for other, unprotected conduct. In holding these and similar issues of absolute immunity to be appealable under the collateral order doctrine, see Abney v. United States, supra; Helstoski v. Meanor, 442 U. S. 500 (1979); Nixon v. Fitzgerald, 457 U. S. 731 (1982), the Court has recognized that a question of immunity is separate from the merits of the underlying action for purposes of the Cohen test even though a reviewing court must consider the plaintiff’s factual allegations in resolving the immunity issue.
  Accordingly, we hold that a district court’s denial of a claim of qualified immunity, to the extent that it turns on an issue of law, is an appealable “final decision” within the meaning of 28 U. S. C. § 1291 notwithstanding the absence of a final judgment.
  IV
  The Court of Appeals thus had jurisdiction over Mitchell’s claim of qualified immunity, and that question was one of the questions presented in the petition for certiorari which we granted without limitation. Moreover, the purely legal question on which Mitchell’s claim of immunity turns is “appropriate for our immediate resolution” notwithstanding that it was not addressed by the Court of Appeals. Nixon v. Fitzgerald, supra, at 743, n. 23. We therefore turn our attention to the merits of Mitchell’s claim of immunity.
  Under Harlow v. Fitzgerald, Mitchell is immune unless his actions violated clearly established law. See 457 U. S., at 818-819; see also Davis v. Scherer, 468 U. S. 183, 197 (1984). Forsyth complains that in November 1970, Mitchell authorized a warrantless wiretap aimed at gathering intelligence regarding a domestic threat to national security — the kind of wiretap that the Court subsequently declared to be illegal. Keith, 407 U. S. 297 (1972). The question of Mitchell’s immunity turns on whether it was clearly established in November 1970, well over a year before Keith was decided, that such wiretaps were unconstitutional. We conclude that it was not.
  The use of warrantless electronic surveillance to gather intelligence in cases involving threats to the Nation’s security can be traced back to 1940, when President Roosevelt instructed Attorney General Robert Jackson that he was authorized to approve wiretaps of persons suspected of subversive activities. In 1946, President Truman’s approval of Attorney General Tom Clark’s request for expanded wiretapping authority made it clear that the Executive Branch perceived its authority to extend to cases involving “domestic security.” See Report of the National Commission for the Review of Federal and State Laws Relating to Wiretapping and Electronic Surveillance 36 (1976). Attorneys General serving Presidents Eisenhower, Kennedy, Johnson, and Nixon continued the practice of employing warrantless electronic surveillance in their efforts to combat perceived threats to the national security, both foreign and domestic. See Keith, supra, at 310-311, n. 10.
  Until 1967, it was anything but clear that these practices violated the Constitution: the Court had ruled in Olmstead v. United States, 277 U. S. 438 (1928), that a wiretap not involving a physical trespass on the property of the person under surveillance was not a search for purposes of the Fourth Amendment, and although the rule in Olmstead had suffered some erosion, see Silverman v. United States, 365 U. S. 505 (1961), the Court had never explicitly disavowed it. Not until 1967 did the Court hold that electronic surveillance unaccompanied by any physical trespass constituted a search subject to the Fourth Amendment’s restrictions, including the Warrant Clause. Katz v. United States, 389 U. S. 347. Yet the Katz Court recognized that warrantless searches do not in all circumstances violate the Fourth Amendment; and though the Court held that no recognized exception to the warrant requirement could justify warrantless wiretapping in an ordinary criminal case, the Court was careful to note that “[wjhether safeguards other than prior authorization by a magistrate would satisfy the Fourth Amendment in a situation involving the national security is a question not presented by this case.” Id., at 358, n. 23. In separate concurrences, Members of the Court debated the question whether the President or the Attorney General could constitutionally authorize warrantless wiretapping in the interest of national security. Compare id., at 359-360 (Douglas, J., joined by Brennan, J., concurring), with id., at 362-364 (White, J., concurring).
  In the aftermath of Katz, Executive authority to order warrantless national security wiretaps remained uncertain. This uncertainty found expression in Title III of the Omnibus Crime Control and Safe Streets Act of 1968, in which Congress attempted to fashion rules governing wiretapping and electronic surveillance that would “meet the constitutional requirements for electronic surveillance enunciated by this Court in Berger v. New York, 388 U. S. 41 (1967), and Katz v. United States, 389 U. S. 347 (1967).” Keith, supra, at 302. Although setting detailed standards governing wiretapping by both state and federal law enforcement agencies, the Act disclaimed any intention “to limit the constitutional power of the President to take such measures as he deems necessary to protect the United States against the overthrow of the Government by force or other unlawful means, or against any other clear and present danger to the structure or existence of the Government.” 18 U. S. C. §2511(3) (1976 ed.). As subsequently interpreted by this Court in Keith, this provision of the Act was an “expression of neutrality,” 407 U. S., at 308, reflecting both an awareness on the part of Congress of the uncertain scope of Executive authority to conduct warrantless national security wiretaps and an unwillingness to circumscribe whatever such authority might exist.
  Uncertainty regarding the legitimacy of warrantless national security wiretapping during the period between Katz and Keith is also reflected in the decisions of the lower federal courts. In a widely cited decision handed down in July 1969, the United States District Court for the Southern District of Texas held that the President, acting through the Attorney General, could legally authorize warrantless wiretaps to gather foreign intelligence in the interest of national security. United States v. Clay, CR. No. 67-H-94 (SD Tex., July 14, 1969), aff’d, 430 F. 2d 165, 171 (CA5 1970), rev’d on other grounds, 403 U. S. 698 (1971). Clay, of course, did not speak to the legality of surveillance directed against domestic threats to the national security, but it was soon applied by two Federal District Courts to uphold the constitutionality of warrantless wiretapping directed against the Black Panthers, a domestic group believed by the Attorney General to constitute a threat to the national security. United States v. Dellinger, No. 69 CR 180 (ND Ill., Feb. 20, 1970) (App. 30), rev’d, 472 F. 2d 340 (CA7 1972); United States v. O’Neal, No. KC-CR-1204 (Kan., Sept. 1, 1970) (App. 38), appeal dism’d, 453 F. 2d 344 (CA10 1972).
  So matters stood when Mitchell authorized the Davidon ■wiretap at issue in this case. Only days after the termination of the Davidon wiretap, however, two District Courts explicitly rejected the Justice Department’s contention that the Attorney General had the authority to order warrantless wiretaps in domestic national security cases. United States v. Smith, 321 F. Supp. 424 (CD Cal., Jan. 8, 1971); United States v. Sinclair, 321 F. Supp. 1074 (ED Mich., Jan. 26, 1971). The Sixth Circuit affirmed the Sinclair decision in United States v. United States District Court for Eastern Dist. of Mich., 444 F. 2d 651 (1971), and our own affirmance followed in 1972. Keith, supra.
  In short, the doctrine of Executive authority to conduct warrantless domestic security wiretaps did not long survive the expiration of the Davidon wiretap. It by no means follows, however, that Mitchell’s actions in authorizing the wiretap violated law that was clearly established at the time of the authorization. As of 1970, the Justice Departments of six successive administrations had considered warrantless domestic security wiretaps constitutional. Only three years earlier, this Court had expressly left open the possibility that this view was correct. Two Federal District Courts had accepted the Justice Department’s position, and although the Sixth Circuit later firmly rejected the notion that the Fourth Amendment countenanced warrantless domestic security wiretapping, this Court found the issue sufficiently doubtful to warrant the exercise of its discretionary jurisdiction. In framing the issue before it, the Keith Court explicitly recognized that the question was one that had yet to receive the definitive answer that it demanded:
  “The issue before us is an important one for the people of our country and their Government. It involves the delicate question of the President’s power, acting through the Attorney General, to authorize electronic surveillance in internal security matters without prior judicial approval. Successive Presidents for more than one-quarter of a century have authorized such surveillance in varying degrees, without guidance from the Congress or a definitive decision of this Court. This case brings the issue here for the first time. Its resolution is a matter of national concern, requiring sensitivity both to the Government’s right to protect itself from unlawful subversion and attack and to the citizen’s right to be secure in his privacy against unreasonable Government intrusion.” 407 U. S., at 299.
  Of course, Keith finally laid to rest the notion that warrant-less wiretapping is permissible in cases involving domestic threats to the national security. But whatever the agreement with the Court’s decision and reasoning in Keith may be, to say that the principle Keith affirmed had already been “clearly established” is to give that phrase a meaning that it cannot easily bear. The legality of the warrantless domestic security wiretap Mitchell authorized in November 1970, was, at that time, an open question, and Harlow teaches that officials performing discretionary functions are not subject to suit when such questions are resolved against them only after they have acted. The District Court’s conclusion that Mitchell is not immune because he gambled and lost on the resolution of this open question departs from the principles of Harlow. Such hindsight-based reasoning on immunity issues is precisely what Harlow rejected. The decisive fact is not that Mitchell’s position turned out to be incorrect, but that the question was open at the time he acted. Hence, in the absence of contrary directions from Congress, Mitchell is immune from suit for his authorization of the Davidon wiretap notwithstanding that his actions violated the Fourth Amendment.
  V
  We affirm the Court of Appeals’ denial of Mitchell’s claim to absolute immunity. The court erred, however, in declining to accept jurisdiction over the question of qualified immunity; and to the extent that the effect of the judgment of the Court of Appeals is to leave standing the District Court’s erroneous decision that Mitchell is not entitled to summary judgment on the ground of qualified immunity, the judgment of the Court of Appeals is reversed.
  It is so ordered.
  Justice Powell took no part in the decision of this case.
  Justice Rehnquist took no part in the consideration or decision of this case.
  Title 18 U. S. C. §2511(3) (1976 ed.) provided:
  “Nothing contained in this chapter or in section 605 of the Communications Act of 1934 (48 Stat. 1143; 47 U. S. C. 605) shall limit the constitutional power of the President to take such measures as he deems necessary to protect the Nation against actual or potential attack or other hostile acts of a foreign power, to obtain foreign intelligence information deemed essential to the security of the United States, or to protect national security information against foreign intelligence activities. Nor shall anything contained in this chapter be deemed to limit the constitutional power of the President to take such measures as he deems necessary to protect the United States against the overthrow of the Government by force or other unlawful means, or against any other clear and present danger to the structure or existence of the Government. The contents of any wire or oral communication intercepted by authority of the President in the exercise of the foregoing powers may be received in evidence in any trial hearing, or other proceeding only where such interception was reasonable, and shall not be otherwise used or disclosed except as is necessary to implement that power” (footnote omitted).
  The provision, enacted as part of Title III of the Omnibus Crime Control and Safe Streets Act of 1968, was repealed in 1978 by § 201(c) of the Foreign Intelligence Surveillance Act, Pub. L. 95-511, 92 Stat. 1797.
  The court also suggested that Mitchell should have been put on notice that his act was unlawful by Title III, which, in its view, clearly proscribed such warrantless wiretaps.
  Forsyth had moved for dismissal of the appeal on the ground that it was interlocutory and therefore not within the Court of Appeals’ jurisdiction under 28 U. S. C. § 1291. A motions panel of the Third Circuit held that the denial of absolute immunity was an appealable order under Nixon v. Fitzgerald, 457 U. S. 731 (1982), and that the issue of the appealability of a denial of qualified immunity was debatable enough to justify referring it to the merits panel. Forsyth v. Kleindienst, 700 F. 2d 104 (1983). Judge Sloviter dissented, arguing that Mitchell’s arguments regarding absolute immunity were frivolous in light of the Third Circuit’s earlier consideration of the same issue. In addition, Judge Sloviter argued that a denial of qualified immunity — unlike a denial of absolute immunity — was not immediately appealable under the collateral order doctrine of Cohen v. Beneficial Industrial Loan Corp., 337 U. S. 541 (1949), because the issue of objective good faith was neither separate from the merits of the underlying action nor effectively unreviewable on appeal from a final judgment.
  Judge Weis, dissenting, argued that the point of the immunity doctrine was protecting officials not only from ultimate liability but also from the trial itself, and that the vindication of this goal required immediate appeal. On the merits, Judge Weis would have reversed the District Court’s immunity ruling on the ground that until Keith was decided it was not clearly established that the warrantless wiretapping in which Mitchell had engaged was illegal.
  The First, Eighth, and District of Columbia Circuits have held such orders appealable, see Krohn v. United States, 742 F. 2d 24 (CA1 1984); Evans v. Dillahunty, 711 F. 2d 828 (CA8 1983); McSurely v. McClellan, 225 U. S. App. D. C. 67, 697 F. 2d 309 (1982), while the Fifth and Seventh Circuits have joined the Third Circuit in holding that the courts of appeals lack jurisdiction over interlocutory appeals of qualified immunity rulings, see Kenyatta v. Moore, 744 F. 2d 1179 (CA5 1984); Lightner v. Jones, 752 F. 2d 1251 (CA7 1985). The Fourth Circuit has held that a district court’s denial of qualified immunity is not appealable when the plaintiff’s action involves claims for injunctive relief that will have to be adjudicated regardless of the resolution of any damages claims. England v. Rockefeller, 739 F. 2d 140 (1984); Bever v. Gilbertson, 724 F. 2d 1083, cert. denied, 469 U. S. 948 (1984). Because this case does not involve a claim for injunctive relief, the propriety of the Fourth Circuit’s approach is not before us, and we express no opinion on the question.
  We recognize that Mitchell himself has faced a significant number of lawsuits stemming from his authorization of warrantless national security wiretaps. See Zweibon v. Mitchell, 231 U. S. App. D. C. 398, 720 F. 2d 162 (1983), cert. denied, 469 U. S. 880 (1984); Sinclair v. Kleindienst, 207 U. S. App. D. C. 155, 645 F. 2d 1080 (1981); Smith v. Nixon, 196 U. S. App. D. C. 276, 606 F. 2d 1183 (1979); Halperin v. Kissinger, 196 U. S. App. D. C. 285, 606 F. 2d 1192 (1979), aff’d by an equally divided Court, 452 U. S. 713 (1981); Weinberg v. Mitchell, 588 F. 2d 275 (CA9 1978); Burkhart v. Saxbe, 596 F. Supp. 96 (ED Pa. 1984); McAlister v. Kleindienst, Civ. Action No. 72-1977 (filed Oct. 10, 1972, ED Pa.). This spate of litigation does not, however, seriously undermine our belief that the Attorney General’s national security duties will not tend to subject him to large numbers of frivolous lawsuits. All of these cases involved warrant-less wiretapping authorized by the Attorney General and were generated by our decision in Keith. They do not suggest that absolute immunity rather than qualified immunity is necessary for the proper performance of the Attorney General’s role in protecting national security.
  It is true that damages actions are not the only conceivable deterrents to constitutional violations by the Attorney General. Mitchell suggests, for example, the possibility of declaratory or injunctive relief and the use of the exclusionary rule to prevent the admission of illegally seized evidence in criminal proceedings. However, as Justice Harlan pointed out in his concurring opinion in Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388, 398-411 (1971), such remedies are useless where a citizen not accused of any crime has been subjected to a completed constitutional violation: in such cases, “it is damages or nothing.” Id., at 410. Other possibilities mentioned by Mitchell — including criminal prosecution and impeachment of the Attorney General — would be of dubious value for deterring all but the most flagrant constitutional violations.
  Similarly, we have held that state-court decisions rejecting a party’s federal-law claim that he is not subject to suit before a particular tribunal are “final” for purposes of our certiorari jurisdiction under 28 U. S. C. § 1257. Mercantile National Bank v. Langdeau, 371 U. S. 555 (1963); Construction Laborers v. Curry, 371 U. S. 542 (1963).
  We emphasize at this point that the appealable issue is a purely legal one: whether the facts alleged (by the plaintiff, or, in some cases, the defendant) support a claim of violation of clearly established law.
  In advancing its view of the “separate from the merits” aspect of the Cohen test, Justice Brennan’s dissent fails to account for our rulings on appealability of denials of claims of double jeopardy and absolute immunity. If, as the dissent seems to suggest, any factual overlap between a collateral issue and the merits of the plaintiff’s claim is fatal to a claim of immediate appealability, none of these matters could be appealed, for all of them require an inquiry into whether the plaintiff’s (or, in the double jeopardy situation, the Government’s) factual allegations state a claim that falls outside the scope of the defendant’s immunity. There is no distinction in principle between the inquiry in such cases and the inquiry where the issue is qualified immunity. Moreover, the dissent’s characterization of the double jeopardy and absolute immunity cases as involving issues that are not “necessarily . . . conclusive or even relevant to the question whether the defendant is ultimately liable on the merits,” post, at 547, is of course inaccurate: meritorious double jeopardy and absolute immunity claims are necessarily directly controlling of the question whether the defendant will ultimately be liable. Indeed, if our holdings on the appealability of double jeopardy and absolute immunity rulings make anything clear it is that the fact that an issue is outcome determinative does not mean that it is not “collateral” for purposes of the Cohen test. The dissent’s explanation that the absolute immunity and double jeopardy cases do not involve a determination of the defendant’s liability “on the merits” similarly fails to distinguish those cases from this one. The reason is that the legal determination that a given proposition of law was not clearly established at the time the defendant committed the alleged acts does not entail a determination of the “merits” of the plaintiff’s claim that the defendant’s actions were in fact unlawful.
  Nor do we see any inconsistency between our ruling here and the handling of the “completely separate from the merits” requirement in Richardson-Merrell Inc. v. Koller, ante, p. 424. Contrary to Justice Brennan’s suggestion, the Richardson-Merrell Court’s alternative holding that the issue of disqualification of counsel in a civil case is not separate from the merits is not based only on the fact that the issue involves some factual overlap with the merits of the underlying litigation. Rather, the Court in Richardson-Merrell observes that the question whether a district court’s disqualification order should be reversed may depend on the effect of disqualification (or nondisqualification) on the success of the parties in litigating the other legal and factual issues that form their underlying dispute. Accordingly, the propriety of a disqualification order — unlike a qualified immunity ruling — is not a legal issue that can be decided with reference only to undisputed facts and in isolation from the remaining issues of the case.
  The District Court’s suggestion that Mitchell’s actions violated clearly established law because they were in conflict with Title III, see n. 2, supra, is therefore expressly contradicted by Keith, in which the Court held that Title III “simply did not legislate with respect to national security surveillances.” 407 U. S., at 306. Given Congress’ express disclaimer of any intention to limit the President’s national security wiretapping powers, it cannot be said that Mitchell’s actions were unlawful under Title III, let alone that they were clearly unlawful. Keith similarly requires rejection of Forsyth’s submission that the legality of the wiretap under Title III is open on remand because it has never been shown that the tap was justified by a “clear and present danger” to the national security. See 18 U. S. C. §2511(3) (1976 ed.). The Keith majority’s handling of the statutory question makes clear that the statutory exemption for national security wiretaps did not depend on a showing of an actual clear and present danger.
  We do not intend to suggest that an official is always immune from liability or suit for a warrantless search merely because the warrant requirement has never explicitly been held to apply to a search conducted in identical circumstances. But in eases where there is a legitimate question whether an exception to the warrant requirement exists, it cannot be said that a warrantless search violates clearly established law.
  Forsyth insists that even if the District Court was incorrect in concluding that warrantless national security wiretaps conducted in 1970-1971 violated clearly established law, Mitchell is not entitled to summary judgment because it has never been found that his actions were in fact motivated by a concern for national security. This submission is untenable. The District Court held a hearing on the purpose of the wiretap and took Mitchell at his word that the wiretap was a national security interception, not a prosecu-torial function for which absolute immunity was recognized. The court then concluded that the tap violated the Fourth Amendment and that Mitchell was not immune from liability for this violation under the Harlow standard. Had the court not concluded that the wiretap was indeed a national security wiretap, the qualified immunity question would never have been reached, for the tap would clearly have been illegal under Title III, and qualified immunity hence unavailable. In this light, the District Court’s handling of the case precludes any suggestion that the wiretap was either (1) authorized for criminal investigatory purposes, or (2) authorized for some purpose unrelated to national security.