HARRY T. EDWARDS, Circuit Judge:

At issue in this appeal is the validity of the District Court's treatment of one aspect of a constitutional tort action, in which the plaintiffs seek compensation for injuries sustained through their exposure to warrantless electronic surveillance. Two questions are presented: Did the District Court err in upholding a formal claim of "state secrets" privilege entered by the United States in opposition to the plaintiffs' motions to compel discovery? Was it proper for the District Court to dismiss those aspects of the suit affected by the government's claim of privilege, on the theory that the plaintiffs would be unable to make out a prima facie case?

We conclude that, while the District Court's accession to the government's state secrets privilege claim was proper for the most part, the court erred in one important respect: it improperly upheld the government's refusal to disclose the identities of the Attorneys General who authorized the wiretaps, despite the absence of any explanation of how the revelation of such information might affect national security. This error was highlighted during the oral argument before this court, when government counsel frankly conceded that there is nothing in the documents or other submissions received by the trial court or this court justifying a refusal by the government to disclose the identities of the responsible Attorneys General. When the District Court's ruling is modified to require disclosure of the names of the officials who ordered the surveillance, it becomes evident that the dismissal of the relevant portions of the suit cannot stand. We thus reverse the judgment and remand the case for further proceedings.

I. BACKGROUND

The plaintiffs in this case were the defendants and their attorneys and advisors in the "Pentagon Papers" criminal prosecution. In the course of that proceeding, they learned that one or more of them had been the subject of warrantless electronic surveillance by the federal government. They subsequently brought this damage action against all persons and agencies they thought might be responsible.

After filing their complaint, the plaintiffs submitted interrogatories to each individual defendant, asking for detailed information regarding the wiretaps. The defendants' responses to the plaintiffs' allegations (and specifically to their request for information) occurred in two phases, separated by approximately four years. In the first phase, the defendants admitted to two wiretaps — one on "one of plaintiffs' attorneys or consultants" and one by the FBI on the telephone at the residence of Morton Halperin, in the course of which "conversations of plaintiff Daniel Ellsberg were incidentally overheard." The defendants refused to respond to any of the plaintiffs' remaining allegations or questions on the ground that all other relevant information was "privileged." Their refusal was buttressed by a formal claim of privilege made on behalf of the United States by then Attorney General (and defendant) Richard Kleindienst. The principal support for Kleindienst's claim was contained in a sealed exhibit, submitted to the District Court for in camera inspection, which contained "records of the intercepted conversations and the identity and location of the premises which were the subjects of the surveillances." That submission — and the inferences to which it assertedly gave rise — were described in a brief public affidavit, the relevant portions of which are reprinted in the margin.

On August 2, 1973, relying on Kleindienst's exhibit and affidavit, the District Court denied the plaintiffs' motion for an order compelling the defendants to answer their interrogatories. Surprisingly, however, the court rested its ruling not on a finding that the government's claim of privilege was proper, but on its conclusions that the two "overhearings" admitted by the defendants were "legal and not violative of any provision of the Constitution of the United States . . . or of any Federal statute" and that the plaintiffs had failed specifically to allege any other injuries sufficient to give them "standing." For purposes relevant to this appeal, that order effectively halted litigation.

The second phase of this suit began on March 29, 1977. On that date, the plaintiffs moved for reconsideration of the District Court's 1973 order, supporting their motion with a memorandum challenging the legal basis of the court's conclusion that they lacked "standing," and submitted a "Request for Production of Documents" relating to the alleged wiretaps. The District Court responded by approving a "stipulation" by the parties, whereby the defendants agreed to recheck their files and make "Fresh Responses" to the plaintiffs' interrogatories. The responses subsequently submitted by the Attorney General, the FBI, the Internal Revenue Service, the Secret Service, the Secretary of State, the Director of Central Intelligence, and the Secretary of Defense went significantly further than the defendants' first set of answers. They admitted that the plaintiffs had been overheard during a number of "domestic intelligence" wiretaps. More importantly for present purposes, they acknowledged "overhears" of five of the plaintiffs — Daniel Ellsberg, Robert Scheer, Leonard B. Boudin, Stanley K. Sheinbaum, and Richard Falk — on "foreign intelligence" taps. In addition, the defendants conceded "foreign intelligence" surveillance of "one or more of the plaintiffs," thus leaving open the possibility that others in the plaintiff class had been overheard. Beyond that, however, the defendants insisted that all other information would be "the subject of a claim of privilege by the head of the appropriate Department or agency."

Four formal claims of privilege were entered in order to explain and justify the defendants' position concerning the "foreign intelligence" surveillance. On August 12, 1977, Attorney General Griffin Bell submitted an in camera exhibit containing information relevant to "the overhearings of plaintiffs Leonard B. Boudin, Thomas Hayden, and Robert Scheer," along with a brief supportive public affidavit. Like the Kleindienst affidavit, on which it appears to have been modeled, the Bell affidavit acknowledged that the taps were "authorized by the Attorney General" but did not indicate which Attorney General was responsible. Subsequently, the Director of Central Intelligence and the Secretary of Defense submitted a total of three in camera affidavits with accompanying exhibits in support of their privilege claims; these latter claims were not, however, accompanied with any public explanation of the nature of the materials or arguments presented to the court.

The plaintiffs then sought an order compelling fuller responses by the defendants. After reviewing in camera the various affidavits and exhibits submitted by representatives of the government and considering the plaintiffs' objections thereto, the District Court concluded that disclosure of the information requested "would reveal sensitive governmental matters related to the national defense and the international relations of the United States" and accordingly denied the motion. On September 2, 1981, the defendants filed a motion in limine, requesting dismissal of those of the plaintiffs' claims that pertain to surveillance of their foreign communications. After hearing argument, the District Court granted the motion and subsequently certified its decision as a partial final judgment subject to review by this court. This appeal followed.

II. THE PRIVILEGE CLAIMS A.

It is now well established that the United States, by invoking its state secrets privilege, may block discovery in a lawsuit of any information that, if disclosed, would adversely affect national security. Prior to World War Two, the government rarely had occasion to exercise this prerogative, and, consequently, the scope of the privilege remained somewhat in doubt. In recent years, however, the state secrets privilege has been asserted in a growing number of cases, and the resultant bevy of judicial decisions assessing the legitimacy of its invocation has brought its lineaments into reasonably sharp focus. The following principles may be distilled from the case law.

The privilege may be asserted only by the government itself; neither a private party nor an individual official may seek its aid. Furthermore, in order to invoke it, "[t]here must be a formal claim of privilege, lodged by the head of the department which has control over the matter, after actual personal consideration by that officer." Possibly because the state secrets doctrine pertains generally to national security concerns, the privilege has been viewed as both expansive and malleable. The various harms, against which protection is sought by invocation of the privilege, include impairment of the nation's defense capabilities, disclosure of intelligence-gathering methods or capabilities, and disruption of diplomatic relations with foreign governments.

When properly invoked, the state secrets privilege is absolute. No competing public or private interest can be advanced to compel disclosure of information found to be protected by a claim of privilege. However, because of the broad sweep of the privilege, the Supreme Court has made clear that "[i]t is not to be lightly invoked." Thus, the privilege may not be used to shield any material not strictly necessary to prevent injury to national security; and, whenever possible, sensitive information must be disentangled from nonsensitive information to allow for the release of the latter.

It has been argued that certain limitations on the capacity of the judicial branch safely and reliably to evaluate invocations of the state secrets privilege should induce the courts to renounce any role in this area, i.e., to accept without question a privilege claim made by a ranking executive officer. Such an extreme solution, however, would have grave drawbacks. As noted by Professor McCormick:

The head of an executive department can appraise the public interest of secrecy as well (or perhaps in some cases better) than the judge, but his official habit and leaning tend to sway him toward a minimizing of the interest of the individual. Under the normal administrative routine the question will come to him with recommendations from cautious subordinates against disclosure and in the press of business the chief is likely to approve the recommendation about such a seemingly minor matter without much independent consideration.

Sensitive to these concerns, the Supreme Court has declared that "[j]udicial control over the evidence in a case cannot be abdicated to the caprice of executive officers." Thus, to ensure that the state secrets privilege is asserted no more frequently and sweepingly than necessary, it is essential that the courts continue critically to examine instances of its invocation.

Although there can be no abdication of a judicial role in connection with proposed applications of the state secrets doctrine, it is nevertheless frequently noted that the trial judge should accord considerable deference to recommendations from the executive department. Moreover, it is recognized that the government need not demonstrate that injury to the national interest will inevitably result from disclosure; a showing of "reasonable danger" that harm will ensue is sufficient. Finally, when assessing claims of a state secrets privilege, a trial judge properly may rely on affidavits and other secondary sources more often than he might when evaluating assertions of other evidentiary privileges.

Whether (and in what spirit) the trial judge in a particular case should examine the materials sought to be withheld depends upon two critical considerations. First, the more compelling a litigant's showing of need for the information in question, the deeper "the court should probe in satisfying itself that the occasion for invoking the privilege is appropriate." Second, the more plausible and substantial the government's allegations of danger to national security, in the context of all the circumstances surrounding the case, the more deferential should be the judge's inquiry into the foundations and scope of the claim. Neither of these two factors can affect the judge's response, however, if he is "ultimately satisfied" that disclosure of the material would damage national security.

B.

With these principles in mind, we turn to the objections made by the plaintiffs to the positions taken by the defendants, the government, and the District Court. The plaintiffs' first argument — a challenge to the scope of the privilege claim — is necessarily somewhat vague. Ignorant of what in fact has been withheld, they are able to say only that "too much" has been shielded. The tasks of posing and answering more specific questions therefore devolve on us.

We have examined all of the various affidavits and exhibits submitted to the District Court for in camera inspection. For the most part, the documents contained therein indicate what the defendants' responses to the plaintiffs' interrogatories would be, and why such responses cannot be made public. With regard to almost all of the material, we find that the District Court was correct in concluding that invocation of the state secrets privilege was proper. In other words, we conclude that there is a "reasonable danger" that revelation of the information in question would either enable a sophisticated analyst to gain insights into the nation's intelligence-gathering methods and capabilities or would disrupt diplomatic relations with foreign governments.

In one important respect, however, we find that the government and the District Court went too far. In their interrogatories, the plaintiffs requested the defendants to state, among other things, "by what . . . form of authority such surveillance was conducted, and if in written form, . . . the name of the person who signed the authorization." In their public affidavits submitted in support of the government's privilege claims, Kleindienst and Bell acknowledged that the wiretaps were "authorized by the Attorney General pursuant to the power delegated to him by the President." However, albeit without justification, neither the defendants nor the representatives of the United States have been willing to specify which Attorneys General authorized the surveillance.

At oral argument, counsel for the defendants conceded that none of the in camera exhibits or accompanying public affidavits submitted by the government explain why the identities of the authorizing officials must be concealed. After examining all the materials presented to the District Court, we agree that the government's concession is fully warranted; further, we can think of no reason why such information should be withheld. The defendants have admitted (indeed insisted) that each tap was authorized by an Attorney General. We cannot see, and the government does not even purport to explain, how any further disruption of diplomatic relations or undesirable education of hostile intelligence analysts would result from naming the responsible officials.

Accordingly, we conclude that the District Court erred in upholding this aspect of the government's claim of privilege. On remand, the defendants should be instructed to identify the Attorneys General who authorized the surveillances.

C.

The plaintiffs' second argument is that the procedures used by the District Court to test the validity of the government's privilege claims were improper. They point out that two of the privilege claims upheld by the District Court were accompanied with no public explanation whatsoever; the affidavits and supporting exhibits submitted by the Director of Central Intelligence and Secretary of Defense were seen only by the trial judge. Additionally, the plaintiffs point out that the brief affidavits submitted on the public record by Attorneys General Kleindienst and Bell allege only that the "national interest" would be "prejudice[d]" by release of the requested materials; what that "interest" consists of and how it might be damaged are not specified. The plaintiffs insist that, confronted with these meager public justifications by the government, the trial judge should have acted in one of two ways. Either he should have permitted the plaintiffs' counsel to participate in the examination of the in camera exhibits or he should have insisted that the government provide a fuller public account of why disclosure of the information would harm national security. At the very least, the plaintiffs maintain, the court should have compelled the government to explain on the public record why a more specific description of the anticipated adverse consequences would itself damage national security.

The first of the plaintiffs' alternative proposals may be disposed of summarily. It is well settled that a trial judge called upon to assess the legitimacy of a state secrets privilege claim should not permit the requester's counsel to participate in an in camera examination of putatively privileged material. Halkin v. Helms [ Halkin I], 598 F.2d 1, 7 (D.C. Cir. 1978); Jabara v. Kelley, 75 F.R.D. 475, 486-87 (E.D.Mich. 1977). The rationale for this rule is that our nation's security is too important to be entrusted to the good faith and circumspection of a litigant's lawyer (whose sense of obligation to his client is likely to strain his fidelity to his pledge of secrecy) or to the coercive power of a protective order.

The plaintiffs' second suggestion makes a good deal more sense. To assess it, we look first to the context in which the District Court was called upon to select a procedure for evaluating the government's privilege claim. We observe that there was a substantial chance that upholding the claim in its entirety would be fatal to the plaintiffs' case. Indeed the District Court subsequently so held. Next, we note that the circumstances surrounding the case certainly did not make it obvious that serious harm to national security would be likely to result from disclosure of the material at issue. This was particularly true at the time the court was evaluating the second set of privilege claims. By then, over five years had elapsed since the last of the wiretaps. More importantly, an official inquiry in the intervening years had resulted in public disclosure not only of the fact that, during the period covered by the suit, our intelligence agencies engaged in very extensive electronic surveillance of both domestic and foreign communications, but of much of the technology whereby such surveillance was effected. Against that background, the harm likely to result from responses to many of the plaintiffs' interrogatories was far from "self-evident."

In short, the plaintiffs made a compelling showing of need for the information in question and the surrounding circumstances did not make apparent the likelihood that disclosure would lead to serious injury. As indicated above, under such conditions, a judge is required to examine carefully a claim of privilege to satisfy himself of its legitimacy. The question then becomes: does such judicial scrutiny require the judge to insist that the government make as complete as possible a public defense of its claims?

Unfortunately, this is one of those procedural issues to which the case law provides no clear solution. Only three decided cases bear on the matter. The two that are directly relevant are flatly inconsistent with one another. Compare Kinoy v. Mitchell, 67 F.R.D. 1, 8 (S.D.N.Y. 1975) (holding that the person claiming the privilege "must set forth, with enough particularity to enable the Court to make an informed decision, the nature of the material withheld and of the threat to the national security should it be revealed"), with Jabara v. Kelley, 75 F.R.D. at 488 (ruling that a general allegation that disclosure "would `prejudice' the national security" was sufficient when supported with secret exhibits). The illumination generated by the third germane case, Halkin I, is weak. Language in the court's opinion provides some slight support for the notion that a requester may demand a full public justification of a privilege claim, 598 F.2d at 6; however, the decision of the court in Halkin I upheld the District Court's refusal to compel the defendants to respond to the plaintiffs' interrogatories seeking to elicit such an explanation.

In the absence of controlling precedent, we must look for insight to judicial experience in related fields, leavening the doctrine developed in those contexts with an appreciation of the important interests at stake when state secrets are alleged to be threatened. In dealing with other evidentiary privileges, courts have acknowledged the utility of a detailed public explanation of the basis of the claim, as a supplement to in camera submission of the requested materials themselves. In Black v. Sheraton Corp., 564 F.2d 531 (D.C. Cir. 1977), for example, we suggested that the proper procedure to be used in evaluating the invocation of a "law enforcement evidentiary privilege" would be to request the government to supply "an index correlating indexed items with particular claims of privilege . . . [along with] an analysis containing descriptions specific enough to identify the basis of the particular claim or claims." Id. at 545. After the plaintiff had been afforded an opportunity "to see this analysis and take issue with its conclusions," the court could examine the materials themselves in camera and make its "final determination." Id.

The considerations underlying this practice are readily apparent. The more specific the public explanation, the greater the ability of the opposing party to contest it. The ensuing arguments assist the judge in assessing the risk of harm posed by dissemination of the information in question. This kind of focused debate is of particular aid to the judge when fulfilling his duty to disentangle privileged from non-privileged materials — to ensure that no more is shielded than is necessary to avoid the anticipated injuries.

Returning to the case before us, we observe that considerable time and resources might have been saved by adherence to the principle that in camera proceedings should be preceded by as full as possible a public debate over the basis and scope of a privilege claim. Had they been afforded an opportunity to contest a detailed justification for the government's claim, the plaintiffs most likely would have been able to demonstrate, at trial, rather than on appeal, the conceded absence of any basis for the refusal to disclose the names of the Attorneys General who authorized the taps. The net result would have been the avoidance of needless delay in the prosecution of the suit.

The foregoing considerations, however, are partially offset by others. Specifically, two concerns prevent us from adopting a strict rule that the trial judge must compel the government to defend its claim publicly before submitting materials in camera. First, it is imperative that the procedure used to evaluate the legitimacy of a state secrets privilege claim not force "disclosure of the very thing the privilege is designed to protect." Fear lest an insufficient public justification result in denial of the privilege entirely might induce the government's representatives to reveal some material that, in the interest of national security, ought not to be uncovered. Second, as was noted at the outset, there is considerable variety in the situations in which a state secrets privilege may be fairly asserted. We would not wish to hobble district courts in designing procedures appropriate to novel cases.

Balancing these various factors, we conclude that, in situations in which close examination of the government's assertions is warranted, the trial judge should insist (1) that the formal claim of privilege be made on the public record and (2) that the government either (a) publicly explain in detail the kinds of injury to national security it seeks to avoid and the reason those harms would result from revelation of the requested information or (b) indicate why such an explanation would itself endanger national security. We wish to make clear the limitations of our ruling: The government's public statement need be no more (and no less) specific than is practicable under the circumstances. We reiterate our holding in Halkin v. Helms [Halkin II], 690 F.2d 977, 995-97 (D.C. Cir. 1982), that the trial judge is not bound to adhere to the strict procedural guidelines developed in the judicial decisions interpreting the Freedom of Information Act, see note 51 supra. Moreover, we do not wish to discourage procedural innovation. We hold simply that, before conducting an in camera examination of the requested materials, the trial judge should be sure that the government has justified its claim in as much detail as is feasible (and would be helpful) without undermining the privilege itself.

III. THE PARTIAL DISMISSAL

Having reversed portions of the District Court's handling of the privilege claims, we might simply remand the case for further proceedings and specifically for reconsideration of the defendants' motion in limine for dismissal of those aspects of the suit pertaining to the "foreign intelligence" wiretaps. To reduce the likelihood of yet another unnecessary appeal, however, we consider it prudent to address briefly some of the problems the trial court will confront on remand.

A.

The effect of the government's successful invocation of the state secrets privilege, when the government is not itself a party to the suit in question, is well established: "[T]he result is simply that the evidence is unavailable, as though a witness had died, and the case will proceed accordingly, with no consequences save those resulting from the loss of the evidence." Likewise, it is now settled that, when the government is a defendant in a civil suit, its invocation of the privilege results in no alteration of pertinent substantive or procedural rules; the effect is the same, in other words, as if the government were not involved in the controversy. The rationale for this doctrine is that the United States, while waiving its sovereign immunity for many purposes, has never consented to an increase in its exposure to liability when it is compelled, for reasons of national security, to refuse to release relevant evidence.

In a somewhat related context, at least one circuit has held that, when one private party brings a civil action against another, and the government asserts a privilege with regard to information in the plaintiff's possession, a ruling that the privilege is valid must be accompanied with a dismissal of the suit. The asserted reason for this seemingly harsh doctrine is that the plaintiff, tempted by the advantages to be gained by as full as possible a disclosure of what he knows, is likely to tread too close to the line drawn by a protective order and occasionally to overstep it.

In an attempt to make out a prima facie case during an actual trial, the plaintiff and its lawyers would have every incentive to probe as close to the core secrets as the trial judge would permit. Such probing in open court would inevitably be revealing.

Outside of this one special context, however, the uniform rule governing civil suits brought by private parties is that the effect of invocation of a state secrets privilege is simply to remove from the case the material in question.

B.

The instant case is a civil action, brought by private parties against various individual defendants and several agencies of the federal government. The information asserted to be privileged is not currently in the plaintiffs' possession. The general principle described above therefore obtains. Under these conditions, dismissal of the relevant portion of the suit would be proper only if the plaintiffs were manifestly unable to make out a prima facie case without the requested information. Are the plaintiffs thus incapacitated?

With regard to those whom the government has not admitted overhearing, the answer is clearly yes. An essential element of each plaintiff's case is proof that he himself has been injured. Membership in a group of people, "one or more" members of which were exposed to surveillance, is insufficient to satisfy that requirement. Dismissal of the claims of those parties was therefore proper.

With regard to the five plaintiffs whom the government has conceded overhearing, the answer is far less obvious. Unlike their colleagues, they can demonstrate injury to themselves. On remand, they will be informed (pursuant to our order today) of the identities of the Attorneys General who authorized the taps during which they were overheard. And the defendants have acknowledged that none of those taps was instituted pursuant to a warrant. Is this complex of facts sufficient to establish a prima facie case of violation of the plaintiffs' constitutional rights?

The defendants argue that the surveillance at issue might have been constitutional. They point out that all courts that have squarely confronted the issue have concluded that warrantless electronic surveillance of foreign agents does not violate the Fourth Amendment provided its primary purpose is not to gather evidence for a criminal prosecution. The defendants concede that the constitutional status of such surveillance has never been determined by the Supreme Court and that the issue remains unresolved in this circuit. But they argue persuasively that, without any developed factual record, it would be inappropriate for us, at least at this stage of the instant case, to try to decide whether or when wiretaps on foreign governments, their agents, or collaborators require prior judicial approval. The plaintiffs respond that the defendants have failed to prove that the taps were in fact directed at foreign agents and were not designed primarily to gather evidence for use in criminal cases, and so have failed to bring themselves within the supposed exception to the warrant requirement. Indeed, the plaintiffs conjecture that it is likely that the taps fell into the category now denominated "domestic security surveillance," which even the defendants admit violates the Fourth Amendment if conducted without a warrant.

In sum, the wiretaps at issue might or might not be unconstitutional (and the evidence necessary to resolve the question cannot be publicly disclosed). Whether this uncertainty dooms the plaintiffs' claims depends on which of the parties bears the burden of persuasion regarding the excusability of the defendants' failure to obtain a warrant. To resolve that question, we must venture briefly into the tangled body of doctrine out of which the (as yet incomplete) law governing electronic surveillance has grown.

The general principle that infuses most decisions dealing with the Fourth Amendment is that, in the absence of special circumstances, the approval of a neutral judicial officer must be obtained before any search or seizure is conducted in a place subject to a reasonable expectation of privacy.

[T]he most basic constitutional rule in this area is that "searches conducted outside the judicial process, without prior approval by judge or magistrate, are per se unreasonable under the Fourth Amendment — subject only to a few specifically established and well-delineated exceptions." The exceptions are "jealously and carefully drawn," and there must be "a showing by those who seek exemption . . . that the exigencies of the situation made that course imperative."

Coolidge v. New Hampshire, 403 U.S. 443, 454-55, 91 S.Ct. 2022, 2031-32, 29 L.Ed.2d 564 (1971) (footnotes omitted). One of the corollaries of that principle is that "the burden is on those seeking [an] exemption to show the need for it." United States v. Jeffers, 342 U.S. 48, 51, 72 S.Ct. 93, 95, 96 L.Ed. 59 (1951).

The reasons in favor of the warrant requirement are, by now, familiar:

We are not dealing with formalities. The presence of a search warrant serves a high function. Absent some grave emergency, the Fourth Amendment has interposed a magistrate between the citizen and the police. This was done not to shield criminals nor to make the home a safe haven for illegal activities. It was done so that an objective mind might weigh the need to invade that privacy in order to enforce the law. The right of privacy was deemed too precious to entrust to the discretion of those whose job is the detection of crime and the arrest of criminals. Power is a heady thing; and history shows that the police acting on their own cannot be trusted. And so the Constitution requires a magistrate to pass on the desires of the police before they violate the privacy of the home. We cannot be true to that constitutional requirement and excuse the absence of a search warrant without a showing by those who seek exemption from the constitutional mandate that the exigencies of the situation made that course imperative.

McDonald v. United States, 335 U.S. 451, 455-56, 69 S.Ct. 191, 193-94, 93 L.Ed. 153 (1948).

As the foregoing passage suggests, judicial insistence upon an affirmative demonstration in each case of the necessity for a relaxation of the warrant requirement has been most marked in the context of physical "searches and seizures that take place on a man's property — his home or office." Coolidge v. New Hampshire, 403 U.S. at 474-75, 91 S.Ct. at 2042-43. Yet, strong considerations also support compliance with the warrant requirement in connection with electronic surveillance. The risk that well-meaning but overly zealous law enforcement officials will either conduct such surveillance without adequate justification or will transgress the bounds of "reasonableness" is at least as great as the danger that they will exceed their authority breaking into homes. And the potential for impingement upon citizens' legitimate expectations of privacy (particularly in view of the fact that, unlike a homeowner, the victim of a wiretap is not even informed of the fact that a "search" is being conducted) is at least as serious. Sensitivity to these concerns has prompted the Supreme Court, in its two seminal decisions dealing with wire-tapping, to extend the warrant requirement first to taps used in the course of routine criminal investigations, Katz v. United States, 389 U.S. 347, 359, 88 S.Ct. 507, 515, 19 L.Ed.2d 576 (1967), and then to taps on "domestic organizations" designed to protect "national security," United States v. United States District Court [Keith], 407 U.S. 297, 308-09, 323-24, 92 S.Ct. 2125, 2132-33, 2139-40, 32 L.Ed.2d 752 (1972).

It is possible, as several courts have concluded, see note 61 supra, that the importance of preserving the power of the executive to act swiftly and vigorously to protect national security may override, in the context of taps on foreign agents, the potent considerations underlying the warrant requirement. But those considerations themselves are in no way diminished. Accordingly, even assuming that the warrant requirement may give way in this special context, there is no reason to relieve those who authorize and conduct such taps of the burden of showing that they come within the exemption.

That conclusion is reinforced by analysis of the probable effects of the alternative rule — namely, that, upon allegation by the government that the wiretaps were on foreign agents and therefore did not require judicial approval, the burden shifts to the victims of the taps to disprove the government's contention. In many such situations, the government would be able (as it has been here) to refuse to disclose any details of the circumstances surrounding the surveillance by invoking its state secrets privilege. The result would be to deny the plaintiffs access to all of the information they need to dispute the government's characterization of the nature and purpose of the surveillance. And the net effect would be to immunize, not only all wiretaps legitimately falling within the hypothesized "foreign agent" exemption, but all other surveillance conducted with equipment or under circumstances sufficiently sensitive to permit assertion of the state secrets privilege. We find such consequences unacceptable.

In summary, we see no reason in the present context to suspend the general rule that the burden is on those seeking an exemption from the Fourth Amendment warrant requirement to show the need for it. Accordingly, to make out a prima facie case of a constitutional violation, the plaintiffs need not disprove the defendants' allegation that their actions are excused by the "foreign agent" exemption; rather, the defendants must prove their contention. As the defendants have not yet made such a showing in the instant case, dismissal of the claims of the five plaintiffs whom the defendants have acknowledged overhearing would be improper.

C.

The foregoing result does give rise to a potential problem: in cases like the present one, the defendant officials who authorized and conducted the surveillance are no more able to use the privileged information in litigation than are the plaintiffs. Enforcement of the rule that the officials bear the burden of proving that they are entitled to an exemption to the warrant requirement thus might lead to serious injustice. Deprived of the ability in practice to adduce the evidence necessary to mount a defense to the plaintiffs' prima facie case, the defendants could be held liable in damages for what in fact was wholly blameless conduct. Such a result not only would be patently inequitable, but might have an unfortunate long-run impact on the recruitment and behavior of government officials.

Fortunately, recent developments in the law governing government officials' immunity from liability provides a way out of this dilemma. Whether a defendant is entitled to "qualified immunity" is now to be determined solely on the basis of an "objective" test:

[G]overnment 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.

Harlow v. Fitzgerald, 457 U.S. 800, 818, 102 S.Ct. 2727, 2738, 73 L.Ed.2d 396 (1982). To a much greater extent than previously, determination of a defendant's immunity will thus turn upon questions of law. Some factual judgments will still be required, but they will be more circumscribed and manageable. Once an official's conduct has been ascertained, the determinative question will be what rules were "clearly established" at the time he acted.

It seems to us that, without serious risk of error, the aforementioned questions could be resolved by the trial judge through use of appropriate in camera procedures. In camera exhibits submitted in support of the government's privilege claim would, in most instances, make clear the nature of the defendants' activities. The judge would thus need only to determine whether clearly established doctrine proscribed such conduct at the time it was undertaken. Such a determination would seem to be possible without the aid of arguments of counsel. And the judge's decision would, of course, be subject to appellate review.

In sum, the practicability of in camera resolution of the immunity issue eliminates the possibility that the defendants — in this case or in future cases — will be trapped by the government's assertion of its state secrets privilege. And that result, in turn, alleviates any qualms we might have concerning the result we reach today.

CONCLUSION

For the foregoing reasons, the decision of the District Court is reversed. The case is remanded for proceedings not inconsistent with this opinion.