Opinion of the Court.

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345 U.S.

of privilege, lodged by the head of the department which has control over the matter," after actual personal consideration by that officer. The court itself must determine whether the circumstances are appropriate for the claim of privilege," and yet do so without forcing a disclosure of the very thing the privilege is designed to protect." The latter requirement is the only one which presents real difficulty. As to it, we find it helpful to draw upon judicial experience in dealing with an analogous privilege, the privilege against self-incrimination.

The privilege against self-incrimination presented the courts with a similar sort of problem. Too much judicial inquiry into the claim of privilege would force disclosure of the thing the privilege was meant to protect, while a complete abandonment of judicial control would lead to intolerable abuses. Indeed, in the earlier stages

19 Firth case, supra, note 16.

20 "The essential matter is that the decision to object should be taken by the minister who is the political head of the department, and that he should have seen and considered the contents of the documents and himself have formed the view that on grounds of public interest they ought not to be produced Duncan v. Cammell, Laird & Co., [1942] A. C. 624, 638. 21 Id., at p. 642:

"Although an objection validly taken to production, on the ground that this would be injurious to the public interest, is conclusive, it is important to remember that the decision ruling out such documents is the decision of the judge. . . . It is the judge who is in control of the trial, not the executive . . . ." (Emphasis supplied.)

22 Id., at pp. 638-642; cf. the language of this Court in Hoffman v. United States, 341 U. S. 479, 486 (1951), speaking of the analogous hazard of probing too far in derogation of the claim of privilege against self-incrimination:

"However, if the witness, upon interposing his claim, were required to prove the hazard in the sense in which a claim is usually required to be established in court, he would be compelled to surrender the very protection which the privilege is designed to guarantee." (Emphasis supplied.)

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Opinion of the Court.

of judicial experience with the problem, both extremes were advocated, some saying that the bare assertion by the witness must be taken as conclusive, and others saying that the witness should be required to reveal the matter behind his claim of privilege to the judge for verification.23 Neither extreme prevailed, and a sound formula of compromise was developed. This formula received authoritative expression in this country as early as the Burr trial. There are differences in phraseology, but in substance it is agreed that the court must be satisfied from all the evidence and circumstances, and "from the implications of the question, in the setting in which it is asked, that a responsive answer to the question or an explanation of why it cannot be answered might be dangerous because injurious disclosure could result." Hoffman v. United States, 341 U. S. 479, 486-487 (1951).25 If the court is so satisfied, the claim of the privilege will be accepted without requiring further disclosure.

Regardless of how it is articulated, some like formula of compromise must be applied here. Judicial control over the evidence in a case cannot be abdicated to the

23 Compare the expressions of Rolfe, B. and Wilde, C. J. in Regina v. Garbett, 2 Car. & K. 474, 492 (1847); see 8 Wigmore on Evidence (3d ed.) § 2271.

24 I Robertson's Reports 244:

"When a question is propounded, it belongs to the court to consider and to decide, whether any direct answer to it can implicate the witness. If this be decided in the negative, then he may answer it without violating the privilege which is secured to him by law. If a direct answer to it may criminate himself, then he must be the sole judge what his answer would be. The court cannot participate with him in this judgment, because they cannot decide on the effect of his answer without knowing what it would be; and a disclosure of that fact to the judges would strip him of the privilege which the law allows, and which he claims."

25 Brown v. United States, 276 U. S. 134 (1928); Mason v. United States, 244 U. S. 362 (1917).

caprice of executive officers. Yet we will not go so far as to say that the court may automatically require a complete disclosure to the judge before the claim of privilege will be accepted in any case. It may be possible to satisfy the court, from all the circumstances of the case, that there is a reasonable danger that compulsion of the evidence will expose military matters which, in the interest of national security, should not be divulged. When this is the case, the occasion for the privilege is appropriate, and the court should not jeopardize the security which the privilege is meant to protect by insisting upon an examination of the evidence, even by the judge alone, in chambers.

In the instant case we cannot escape judicial notice that this is a time of vigorous preparation for national defense. Experience in the past war has made it common knowledge that air power is one of the most potent weapons in our scheme of defense, and that newly developing electronic devices have greatly enhanced the effective use of air power. It is equally apparent that these electronic devices must be kept secret if their full military advantage is to be exploited in the national interests. On the record before the trial court it appeared that this accident occurred to a military plane which had gone aloft to test secret electronic equipment. Certainly there was a reasonable danger that the accident investigation report would contain references to the secret electronic equipment which was the primary concern of the mission.

Of course, even with this information before him, the trial judge was in no position to decide that the report was privileged until there had been a formal claim of privilege. Thus it was entirely proper to rule initially that petitioner had shown probable cause for discovery of the documents. Thereafter, when the formal claim of privilege was filed by the Secretary of the Air Force, under

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Opinion of the Court.

circumstances indicating a reasonable possibility that military secrets were involved, there was certainly a sufficient showing of privilege to cut off further demand for the documents on the showing of necessity for its compulsion that had then been made.

26

In each case, the showing of necessity which is made. will determine how far the court should probe in satisfying itself that the occasion for invoking the privilege is appropriate. Where there is a strong showing of necessity, the claim of privilege should not be lightly accepted, but even the most compelling necessity cannot overcome the claim of privilege if the court is ultimately satisfied that military secrets are at stake. A fortiori, where necessity is dubious, a formal claim of privilege, made under the circumstances of this case, will have to prevail. Here, necessity was greatly minimized by an available alternative, which might have given respondents the evidence to make out their case without forcing a showdown on the claim of privilege. By their failure to pursue that alternative, respondents have posed the privilege question for decision with the formal claim of privilege set against a dubious showing of necessity.

There is nothing to suggest that the electronic equipment, in this case, had any causal connection with the accident. Therefore, it should be possible for respondents to adduce the essential facts as to causation without resort to material touching upon military secrets. Respondents were given a reasonable opportunity to do just that, when petitioner formally offered to make the surviving crew members available for examination. We think that offer should have been accepted.

26 See Totten v. United States, 92 U. S. 105 (1875), where the very subject matter of the action, a contract to perform espionage, was a matter of state secret. The action was dismissed on the pleadings without ever reaching the question of evidence, since it was so obvious that the action should never prevail over the privilege.

Respondents have cited us to those cases in the criminal field, where it has been held that the Government can invoke its evidentiary privileges only at the price of letting the defendant go free." The rationale of the criminal cases is that, since the Government which prosecutes an accused also has the duty to see that justice is done, it is unconscionable to allow it to undertake prosecution and then invoke its governmental privileges to deprive the accused of anything which might be material to his defense. Such rationale has no application in a civil forum where the Government is not the moving party, but is a defendant only on terms to which it has consented.

The decision of the Court of Appeals is reversed and the case will be remanded to the District Court for further proceedings consistent with the views expressed in this opinion.

Reversed and remanded.

MR. JUSTICE BLACK, MR. JUSTICE FRANKFURTER, and MR. JUSTICE JACKSON dissent, substantially for the reasons set forth in the opinion of Judge Maris below. 192 F. 2d 987.

2 United States v. Andolschek, 142 F. 2d 503 (C. A. 2d Cir. 1944); United States v. Beekman, 155 F. 2d 580 (C. A. 2d Cir. 1946).