Opinion for the Court filed by Circuit Judge ROBINSON.
Dissenting Opinion filed by Circuit Judge BORK.
[27] SP0TTSW00D W. KOBINSON, III, Circuit Judge:
This appeal summons us to examine this case a second time. Again at issue is an order of the District Court requiring production by the Department of State1 of certain documents2 requested by the Washington Post Company (the Post) pursuant to the Freedom of Information Act (FOIA).3 In that court the Department contended, as it does here, that revelation of these materials would “constitute a clearly unwarranted invasion of personal privacy,” and, accordingly, that they are exempted from mandatory release by FOIA’s Exemption 6.4 The District Court entered summary judgment for the Post on the ground that the strong public interest in disclosure of governmental information outweighed what the court deemed would amount to a relatively insignificant invasion of privacy.5
We hold that in the circumstances portrayed by the record, the information solicited by the Post is potentially accessible under FOIA. We find, however, that the District Court undertook to resolve a serious factual dispute concerning the extent of harm consequent upon an unveiling of that information. We therefore reverse the production order and remand the case to that court for further proceedings in harmony with this opinion.
I.The Background
In September, 1979, the Post asked the State Department to release, pursuant to FOIA, any documents indicating whether Dr. Ali Behzadnia and Dr. Ibrahim Yazdi were United States citizens or held valid United States passports.6 At the time, both of these individuals lived in Iran and were prominent figures in the governmental hierarchy of that country. The Department denied the Post’s request, invoking FOIA Exemption 6, which authorizes withholding of “personnel and medical files and similar files the disclosure of which would constitute a clearly unwarranted invasion of personal privacy.”7 The Department asserted that disclosure of any record revealing that Dr. Behzadnia or Dr. Yazdi is a naturalized United States citizen would result in embarrassment and physical harm, and possibly even death.8 This disposition was affirmed by the Department’s Council on Classification Policy, which felt that “the privacy interests to be protected are not incidental ones, but, rather are such that they clearly outweigh any public interests which might be served by release of the requested information.”9
The Post then instituted the present suit in the District Court to enjoin the State Department from withholding the data requested.10 That court held that the records in question are not “similar files” protected by Exemption 6, and accordingly granted summary judgment for the Post.11 On appeal, this court agreed that the records are not “similar files,” and therefore did not consider the possible impact of disclosure [28] upon any privacy interest involved.12 The Supreme Court, however, finding this reading of “similar files” too narrow, reversed.13 The Court held that Congress intended that the phrase be given a broad meaning, and thus to include any file containing “[gjovernment records on an individual which can be identified as applying to that individual.”14 This court in turn remanded to the District Court for determination of whether public release of such records would amount to an intrusion upon personal privacy above the statutorily tolerated level.15
Subsequently, the State Department learned that Dr. Behzadnia was no longer living in Iran. The Department then sought to comply with the Post's request as to him, but was unable to locate any material relating to issuance of a United States passport to him or any other document associated with his name.16 From that point the case proceeded with respect to Dr. Yazdi alone.
Both sides moved for summary judgment in the District Court, thus confronting it with the task of balancing the public interest in disclosure against the privacy interest of Dr. Yazdi. The State Department relied on affidavits averring that public dissemination of the information desired by the Post could be embarrassing to Dr. Yaz-di and could even expose him to physical harm.17 The Post, on the other hand, pointed to several press accounts of events in Iran, and to books published since the Iranian Revolution that had referred to Dr. Yazdi’s reputed ties to the United States. For example, both Inside the Iranian Revolution, by a former director of the State Department operations center, and Mission to Iran, by a former ambassador to Iran, state that Yazdi is a United States citizen.18 Because information of that character was already in the public domain and the dire consequences predicted by the State Department had not occurred, the District Court concluded that the effect on personal privacy from release of the requested documents would be insubstantial.19
[29] Against this personal privacy interest the District Court balanced what it found to be a strong public interest in favor of disclosure. The court identified two elements of this public interest. First, the court observed that whether prominent officials of the Iranian government are American citizens is a legitimate matter of public concern, especially because such information “would shed light on the backgrounds and motivations of these individuals and on the composition of the body of officials exercising political power in Iran.”20 Second, the court declared that this information would reveal what steps, if any, the United States Government had taken to revoke the order naturalizing Dr. Yazdi and to cancel his certificate of naturalization.21 The records pursued by the Post might show, the court reasoned, whether governmental officials had been derelict in their duties by failing to institute proceedings toward that end.22 Weighing this public interest against Dr. Yazdi’s privacy interest, the court found that disclosure of the soughtrafter information would not constitute a clearly unwarranted invasion of privacy.23
II. The Summary Judgment
Time and again, this court has emphasized that FOIA cases are not immune to summary-judgment requirements.24 Only upon a suitable showing “that there is no genuine issue as to any material fact and that the moving party is entitled to a judgment as a matter of law” is summary judgment in order.25 By the same token, an agency may not defeat its opponent’s right to an evidentiary hearing on such an issue merely by filing an affidavit purporting to support a motion for such a judgment.26 Rather, “the requester may ... produce countervailing evidence,”27 and if any genuine issue of material fact remains, summary judgment is improper.28
In light of these uncontroversial precepts, the District Court erred in awarding summary judgment to the Post. The record makes abundantly clear a factual dispute going to the very heart of the case: the extent of potential harm to Dr. Yazdi should the Department release information on his citizenship.29 That issue could prop[30] erly be resolved only by trial, not by fact-finding on the basis of materials tendered in support of and in opposition to summary judgment.30
When we review refused FOIA requests, we are often called upon to assess the probable consequences of releasing particular information. And when the litigants quarrel over key factual premises for a determination on that score, we have unhesitatingly ruled that summary judgment is inappropriate. For instance, as our Exemption 431 cases well illustrate, we have frequently found that disputes over the likelihood or extent of harm from disclosure preclude summary judgment:
Where there is a conflict in the affidavits as to what adverse consequences will flow from the revelation of the facts contained in the documents sought to be disclosed, then it appears that there is indeed a conflict regarding very material facts which calls for some type of adversary procedure. The District Court thus attempted to resolve the conflict in the ultimate facts without having the evidence before it.... Summary judgment was not appropriate.32
Similarly, in applying the privacy-balancing test of Exemption 7(C),33 we have held that “differing assessments of the actual harm which disclosure would inflict” generate an issue of fact unsuitable for resolution on summary judgment.34 The same conclusion follows inexorably here.
Facing controverted issues of fact, the District Court proceeded to resolve a pivotal conflict in the affidavits respectively tendered by the Post and the State Department on the cross-motions for summary judgment.35 Courts are forbidden, however, to conduct trial by affidavit and thus deprive litigants of their right to an eviden-tiary hearing on issues of fact.36 As we have said in the past, “[w]e think there is a right of confrontation ... and so the parties should have the right to examine the affiants either by depositions or in open court.... [T]he case should be tried like any other adversary proceeding.”37
This limitation on the use of summary judgment is not a mere technicality. The [31] integrity of a court’s de novo judgment rests upon an adversarial system of testing for truth when critical adjudicative facts are subjects of a contest.38 Obviously, the more difficult the issues and equal the weight of expert opinion in a case, the greater the role that process plays in honing the court’s judgment. It is no wonder, then, that we have recognized “the advantages of adversary procedures in testing the strength of the government’s position in FOIA cases,”39 and have declared that “[t]he importance of maximizing adversary procedures in suits such as this cannot be gain-said.”40 On remand, the District Court must heed these teachings, and resort to some salutary alternative to summary judgment.
III. The Degree of Deference Due the State Department
Our dissenting colleague, however, would direct an award of summary judgment, not to the Post, but instead to the State Department. The rationale for that course is that an evidentary hearing of this question would be “wholly unsuited to the capacities of the judicial process.”41 Put another way, the dissent contends that we must defer to the State Department’s assessment of the seriousness of the threat of harm to Dr. Yazdi because the courts lack the ability to deal with it. This thesis, advanced relentlessly and with singular energy, disregards firm precedent, ignores the lengthening record of satisfactory judicial performance in adjudication of questions of predictive fact under FOIA, and counsels an abdication of judicial responsibility to unbridled Executive Branch discretion in defiance of an explicit congressional directive that courts review agency withholding claims de novo.
A. The Obligation to Review De Novo
When FOIA was originally enacted in 1967, Congress foresaw the need for de novo judicial review42 “in order that the [32] ultimate decision as to the propriety of the agency’s action is made by the court and [to] prevent [the proceeding] from becoming meaningless judicial sanctioning of agency discretion.”43 In all cases, it was the reviewing court, not the agency subjected to review, that was ultimately to determine the propriety of the agency’s action in withholding the requested information.44 In 1974, Congress reaffirmed and strengthened this position in the face of a strenuous effort to legislate a narrower standard for review of Exemption 1 claims premised on exigencies of the national security.45 As we have characterized the result,
[t]he [1974] legislative history underscores that the intent of Congress regarding de novo review stood in contrast to, and was a rejection of, the alternative suggestion ... that in the national security context the court should be limited to determining whether there was a reasonable basis for the decision by the appropriate official to withhold the document.46
In light of this development, how can it be maintained that Exemption 6 privacy claims call for anything less than full de novo review? These claims are very different from Exemption 1 national security claims, and accordingly the arguments for judicial deference in the Exemption 1 context have no force when a court weighs a personal privacy interest. More startlingly, the approach advocated by the dissent would involve deference to a degree even beyond that envisioned by congressional proponents of a narrow scope of judicial review in the national security context. Although Congress expressly provided for de novo review of Exemption 6 claims and did not prescribe any special deference to agency judgments underlying them, the dissent urges us to defer to the State Department, on the grounds that judges know too little about conditions in Iran to second-guess the agency 47 and that “any reader of the Washington Post” — including, presumably, judges — can see that the State Department prediction “is very plausible.”48
Such an exercise in institutional self-denegration would flatly ignore the oversight function that Congress imposed on the courts. In addition to the express statutory command to review agency withhold-ings de novo, the legislative record is replete with indicia of congressional confidence in the capacity of the judiciary to evaluate FOIA questions bearing on national security and foreign policy. Before examining the reviewing stance appropriate to disposition of the instant appeal, we revisit the record to demonstrate the unequivocal conviction of Congress that courts can and should review FOIA requests implicating factors of the sort operative here.
B. De Novo Review in the Exemption 1 Context
When Congress amended FOIA in 1974, it did so in significant part to reverse the Supreme Court’s decision in EPA v. [33] Mink,49 which had foreclosed in camera inspection of classified documents.50 Representative Mink, the plaintiff in that case, explained the purpose of Congress:
Our intention in making this change is to place a judicial check on arbitrary actions by the Executive to withhold information that might be embarrassing, politically sensitive, or otherwise concealed for improper reasons rather than truly vital to national defense or foreign policy. We are not saying that any material must be released, only that it must be submitted to an impartial judge to determine whether its withholding meets the provisions and purposes of the act.51
Adoption of the in camera inspection provision of the Act sparked extensive debate on the standard appropriate for judicial review of Exemption 1 claims. The bill, as reported out by the Senate Judiciary Committee, stipulated that an exemption claim involving classified material was to be sustained unless it was determined that the decision to classify lacked a reasonable basis under criteria set forth by the govem-ing executive order.52 Senator Muskie, however, introduced an amendment to remove this language, warning that the statutory “presumption”53 contained in the committee bill would “make the independent judicial evaluation meaningless ... go[ing] far to reduce the judicial role to that of a mere concurrence in Executive decisionmaking.”54 Review of classification decisions, the Senator urged, ought to turn on the merits of the exemption claim rather than the force of a statutory presumption.55 And, emphasizing the importance of review de novo,56 the Senator had no doubt as to the ability of judges to make the necessary determinations:
By telling judges so specifically how to manage their inquiry into the propriety of a classification marking, we show a strange contempt for their ability to devise procedures on their own to help them reach a just decision. Moreover, by giving classified material a status unlike that of any other claimed Government secret, we foster the outworn myth that only those in possession of military and [34] diplomatic confidences can have the expertise to decide with whom and when to share their knowledge. ... I object to the idea that anything but full de novo review will give us the assurance that classification ... has been brought under check.... I cannot understand why we should trust a Federal judge to be able to sort out valid from invalid claims of Executive privilege in the Watergate affair but not trust him or his colleagues to make the same unfettered judgments in matters allegedly connected to the conduct of defense or foreign policy.57
Opponents of the Muskie amendment raised the spectre of judicial shortcomings that the dissent resurrects today,58 but the arguments of the proponents prevailed. The Senate passed the amendment by a vote of 56 to 29.59 Thereafter, the Conference Committee adopted the in camera inspection provision of the Senate bill as amended, adding no more than a directive that “courts, in making de novo determinations in [Exemption 1] cases, ... will accord substantial weight to an agency’s affidavit concerning the details of the classified status of the disputed record.”60 The House then accepted, by the overwhelming margin of 349 to 2, the Conference bill authorizing in camera inspection on review of Exemption 1 claims.61
President Ford, however, contending that “the courts should not be forced to make ... [decisions] in sensitive and complex areas where they have no particular expertise,” 62 vetoed the legislation and the debate resumed. Members of both Houses again voiced their confidence in the competence of the courts to review Exemption 1 claims de novo,63 and voted resoundingly to [35] override the veto.64 As we have observed en banc, “this vote of confidence in the competence of the judiciary affirms our own belief that judges do, in fact, have the capabilities needed to consider and weigh data pertaining to the foreign affairs and national defense of this nation.”65
C. De Novo Review in the Instant Case
In balancing the disclosure and the privacy interests staked out in this case, the District Court will have to engage in a searching de novo examination of the evidence to be introduced before it in order to gauge the likely consequences of revealing the citizenship information requested by the Post. We have already demonstrated that unquestioning deference to the State Department’s affidavits would be unseemly in an Exemption 1 context, and the more so where, as here, no claim of national security or foreign policy concern has been advanced.66
[36] Nor, in our view, is a holding in favor of the Department required by what the dissent characterizes as “common sense.”67 Much of the content of the Department’s affidavits is contradicted by concrete evidence identified by the Post.68 And what[37] ever weight the opinion of the Department, as a presumed expert in the foreign relations field, is able to garner, deference cannot extend to blatant disregard of countervailing evidence.69 Indeed, it is ironic that the dissent should propose to resolve through “common sense” an issue it claims lies beyond the competence of the judiciary.
The central question in this litigation is one of predictive fact — the expectable consequences of a public release of particular information. Though Congress has conferred “substantial weight” upon agency affidavits only in Exemption 1 cases,70 the State Department’s affidavits in this case are still entitled to careful consideration. But, when, as here, conclusions drawn in agency affidavits are hotly contested by other evidence, both the need for and the propriety of a judicial resolution emerge.
The State Department’s affidavits predict that Iranians who have connections with the United States face possible harm. One of two affidavits upon which the Department relies heavily states that “[a]n official of the Government of Iran who is reputed to be an American citizen would, in my opinion, be in physical danger from some of the revolutionary groups that are prone to violence.”71 Another affidavit avers that “there continues to be intense anti-American sentiment in Iran and several revolutionary leaders have been strongly criticized in the press for their alleged ties to the United States. Any person suspected of having such a connection would likely be subject to severe scrutiny, suspicion and possible harm.”72 Yet, as we have noted, there already has been widespread public speculation concerning a relationship between Dr. Yazdi and the United States. There have been published accounts, drawing on sources both within and without the United States Government,73 that would appear more than sufficient to provoke the reprisals the Department dreads. But, as the District Court observed and neither party has disputed, “the danger anticipated by the affidavits submitted by [the Department] has not materialized. On the contrary, in months following that report, Dr. Yazdi’s governmental responsibilities, according to [the Department’s] affidavits, were increased.”74 The publicity given Dr. Yazdi’s alleged United States citizenship, the fact that he has not been the subject of retaliation, and the further fact that he seemingly enjoys heightened status in the Iranian Government, combine to pointedly controvert the Department’s prediction of harm from disclosure of the documents the Post wishes to inspect.
It was not until the Department’s motion for summary judgment was filed — four years after the Post’s initial FOIA request — that the Department advanced the contention that the threat to Dr. Yazdi arises not so much from unverified information about a United States citizenship as from “official confirmation” thereof.75 [38] Certainly under some circumstances official corroboration may have effects qualitatively different from those emanating from unofficial information already publicly known.76 But whether a particular confirmation likely will produce a more profound effect, or increase an effect beyond a legally acceptable limit, is clearly a question of fact, and as such an appropriate subject of inquiry at an evidentiary hearing.77
Moreover, outright deference to the State Department’s risk appraisal would ignore the Supreme Court’s admonition, in earlier remanding this very case, that “[t]he public nature of information may be a reason to conclude, under all the circumstances of a given case, that the release of such information would not constitute a ‘clearly unwarranted invasion of personal privacy.’ ”78 Although this “implies] the existence of a low-level privacy interest in ... records despite their public availability somewhere in the nation,”79 it also suggests that the interest fades commensurately with public availability of those records. We recently recognized that in some cases the dissemination of already-public information may result in “particular harm” to an individual and counsels against disclosure.80 The existence of “particular harm” in this case, however, depends precisely upon the resolution of an issue of predictive fact, which renders an evidentiary exploration indispensable.
IV. Considerations on Remand
For the reasons discussed, we remand this case to the District Court for further proceedings leading eventually to appropriate factfinding should any issue of material fact persist. This remand will serve several highly useful purposes. First, we note that the District Court denied the Post any opportunity for discovery.81 In FOIA cases, as in other litigation, discovery is an important tool for truth-testing,82 and each mode of discovery requested by the Post83 was appropriate in a FOIA action.84 The Post made known [39] that its discovery efforts were directed toward ascertaining any factual premises for the Department’s estimate of resulting harm to Dr. Yazdi, the basis for the Department’s assertion that already-public information on Dr. Yazdi’s citizenship would not dissipate any such harm, and the Department’s role in prior disclosures by certain of its former employees and the Immigration and Naturalization Service.85 The discovery proposed by the Post thus would have borne directly on the all-important question of potential harm to Dr. Yazdi from release of the documents requested. With these discovery objectives, there is hardly any risk of accidental disclosure of putatively exempted material, a factor that has been crucial to limitations on discovery in other FOIA cases.86
After completion of discovery, a hearing might be necessary to evaluate conflicting evidence.87 The Post should be afforded the opportunity to cross-examine the Department’s witnesses and, of course, the Department should enjoy the same option respecting witnesses selected by the Post.88 Similarly, both sides should be allowed to present the testimony of expert witnesses,89 and non-experts with first-hand knowledge on the state of affairs in Iran, particularly with respect to attitudes toward Iranians having political connections with the United States.90
V. Conclusion
We reverse the District Court’s summary judgment in favor of the Post. We also reject the contention that predictive judgments by the State Department on the nature and impact of future behavior of foreign nations and their citizens are inviolate in Exemption 6 proceedings. We direct the District Court to accord the parties full de novo review, and we hold that unless the Department discharges its burden of sus-[40] taming its action,91 the mandatory disclosure directive of FOIA will require release of documents requested. We remand this case to the District Court for further proceedings consistent with this opinion.
So ordered.