with whom Justice Brennan joins, concurring in the result.
To give meaning to the term “intelligence source” as it is used in § 102(d)(3) of the National Security Act of 1947, the Court today correctly concludes that the very narrow definition offered by the Court of Appeals is incorrect.1 That the *182Court of Appeals erred does not, however, compel the conclusion that the Agency’s sweeping alternative definition is in fact the correct one.2 The Court nonetheless simply adopts wholesale the Agency’s definition of “intelligence source.” That definition is mandated neither by the language or legislative history of any congressional Act, nor by legitimate policy considerations, and it in fact thwarts congressional efforts to balance the public’s interest in information and the Government’s need for secrecy. I therefore decline to join the opinion of the Court.
I
The Freedom of Information Act (FOIA or Act) established a broad mandate for disclosure of governmental information by requiring that all materials be made public “unless explicitly allowed to be kept secret by one of the exemptions . . . .” S. Rep. No. 813, 89th Cong., 1st Sess., 10 (1965). The Act requires courts to review de novo agency claims of exemption, and it places on the agency the burden of defending its withholding of information. 5 U. S. C. § 552(a)(4)(B). Congress, it is clear, sought to assure that the Government would not operate behind a véil of secrecy, and it narrowly tailored the exceptions to the fundamental goal of disclosure.
Two of these few exceptions are at issue in this case. The first, on which the Court focuses, is Exemption 3, which exempts information “specifically exempted from disclosure by statute,” if the statute affords the agency no discretion on disclosure, § 552(b)(3)(A), establishes particular criteria for withholding the information, § 552(b)(3)(B), or refers to the particular types of material to be withheld, ibid. The Court *183quite rightly identifies § 102(d)(3) of the National Security Act as a statutory exemption of the kind to which Exemption 3 refers; that section places with the Director of Central Intelligence the responsibility for “protecting intelligence sources and methods from unauthorized disclosure.”
A second exemption, known as Exemption 1, covers matters that are “(A) specifically authorized under criteria established by an Executive order to be kept secret in the interest of national defense or foreign policy and (B) are in fact properly classified pursuant to such Executive order.” 5 U. S. C. § 552(b)(1). This latter Exemption gives to the Executive Branch the authority to define material that will not be disclosed, subject of course to congressional amendment of the Exemption. Agency decisions to withhold are subject to de novo review in the courts, which must ascertain whether documents are correctly classified, both substantively and procedurally.
Exemption 1 is the keystone of a congressional scheme that balances deference to the Executive’s interest in maintaining secrecy with continued judicial and congressional oversight. In the past, Congress has taken affirmative steps to make clear the importance of this oversight. See n. 5, infra. Exemption 1 allows the Government to protect from the scrutiny of this Nation’s enemies classes of information that warrant protection, as long as the Government proceeds through a publicly issued, congressionally scrutinized, and judicially enforced executive order. See Hearing on Executive Order on Security Classification before the Subcommittee of the Committee on Government Operations of the House of Representatives, 97th Cong., 2d Sess. (1982) (Hearing).
Exemption 1 thus plays a crucial role in the protection of Central Intelligence Agency information. That the Court does not mention this Exemption even once, in the course of its lengthy analysis on the policy reasons for broadly inter*184preting the “intelligence source” provision, is extraordinary. By focusing myopically on the single statutory provision on which the Agency has chosen to rely in asserting its secrecy right, the Court rewards the Agency’s decision not to invoke Exemption 1 in these cases.3 Of course, the Agency may fairly assert any possible ground for decision, and it has no duty to select that which is narrowest. But the Court, intent to assure that important information is protected, today plays into the Agency’s hands by stretching the “intelligence source” exception beyond its natural limit; it does so while simply ignoring the fact that the information sought could properly have been withheld on other grounds — on which the Agency chose not to rely. The cost of acceding to the Agency’s litigation strategy, rather than undertaking a thorough analysis of the entire statutory scheme, is to mangle, seriously, a carefully crafted statutory scheme.
J — l HH
I turn, then, to consider in light of this statutory framework the Court’s analysis of Exemption 3. After concluding that Exemption 3 incorporates § 102(d)(3) as a withholding provision, the Court sets out to define the term “intelligence source.” First, it looks to the “plain meaning” of the phrase and concludes that an “intelligence source” is self-evidently the same as an “information source.” Ante, at 169-170. Second, the Court looks to the legislative history. Pulling *185together pieces of testimony from congressional hearings on the need to establish a centralized agency to gather information, it concludes that Congress knew that the Agency would collect information from diverse sources, and that “Congress was plainly alert to the need for maintaining confidentiality” so as not to lose covert sources of information. Ante, at 172; see also Brief for Petitioners in No. 83-1075, pp. 18-21. Third, the Court chastises the Court of Appeals for adopting a “crabbed” reading of the statute and explains how, as a policy matter, the “forced disclosure of the identities of its intelligence sources could well have a devastating impact on the Agency’s ability to carry out its mission.” Ante, at 175; see also Brief for Petitioners in No. 83-1075, p. 31. The Court offers examples of highly sensitive information that, under the lower court’s reading, might be disclosed. See ante, at 176-177; see also Brief for Petitioners in No. 83-1075, pp. 34-37.
Before this Court, the Agency argued against the lower court’s definition of “intelligence source,” substituted its own sweeping offering, and then recounted a litany of national security nightmares that would surely befall this Nation under any lesser standard; today the Court simply buys this analysis. But the Court thereby ignores several important facts. First, the holding today is not compelled by the language of the statute, nor by the legislative history on which the Court relies. Second, the Court of Appeals’ definition is not the sole alternative to the one adopted by the Court today. Third, as noted, supra, other broad exemptions to FOIA exist, and a holding that this Exemption 3 exception does not apply here would in no way pose the risk of broad disclosure the Agency suggests. The Court’s reliance on the Nation’s national security interests is simply misplaced given that the “intelligence source” exemption in the National Security Act is far from the Agency’s exclusive, or most potent, resource for keeping probing eyes from secret documents. In its haste to adopt the Agency’s sweeping defini*186tion, the Court completely bypasses a considerably more rational definition that comports at least as well with the statutory language and legislative history, and that maintains the congressionally imposed limits on the Agency’s exercise of discretion in this area.
To my mind, the phrase “intelligence source” refers only to sources who provide information either on an express or implied promise of confidentiality, and the exemption protects such information and material that would lead to disclosure of such information. This reading is amply supported by the language of the statute and its history.
First, I find reliance on “plain meaning” wholly inappropriate. The heart of the issue is whether the term “intelligence source” connotes that which is confidential or clandestine, and the answer is far from obvious. The term is readily susceptible of many interpretations, and in the past the Government itself has defined the term far less broadly than it now does before this Court. In testimony before the House Subcommittee on Government Operations on President Reagan’s Exemption 1 Executive Order, Steven Garfinkel, Director of the Information Security Oversight Office, explained that the term “intelligence source” is narrow and does not encompass even all confidential sources of information:
“[CJertain of these sources are not ‘intelligence sources.’ They are not involved in intelligence agencies or in intelligence work. They happen to be sources of information received by these agencies in confidence.” Hearing, at 204.
The current administration’s definition of the term “intelligence source” as used in its Executive Order does not, of course, control our interpretation of a longstanding statute. But the fact that the same administration has read the phrase in different ways for different purposes certainly undercuts the Court’s argument that the phrase has any single and readily apparent definition.
*187“[PJlain meaning, like beauty, is sometimes in the eye of the beholder,” Florida Power & Light Co. v. Lorion, 470 U. S. 729, 737 (1985), and in an instance such as this one, in which the term at issue carries with it more than one plausible meaning, it is simply inappropriate to select a single reading and label it the “plain meaning.” The Court, like the Government, argues that the statute does not say “confidential source,” as it might were its scope limited to sources who have received an implied or express promise of confidentiality. See ante, at 169, and n. 13; Brief for Petitioners in No. 83-1075, p. 16. However, the statute also does not say “information source” as it might were it meant to define the class of material that the Court identifies. I therefore reject the Court’s basic premise that the language at issue necessarily has but a single, obvious interpretation.
Nor does the legislative history suggest anything other than a congressional desire to protect those individuals who might either be harmed or silenced should their identities or assistance become known. The congressional hearings quoted by the Court, and by the Government in its brief, focus on Congress’ concern about the “deadly peril” faced by intelligence sources if their identities were revealed, and about the possibility that those sources would “ ‘close up like a clam’” without protection. See ante, at 172; Brief for Petitioners in No. 83-1075, p. 20. These concerns are fully addressed by preventing disclosure of the identities of sources who might face peril, or cease providing information, if their identities were known, and of other information that might lead an observer to identify such sources. That, to my mind, is the start and finish of the exemption for an “intelligence source” — one who contributes information on an implicit understanding or explicit assurance of confidentiality, as well as information that could lead to such a source.4
*188This reading of the “intelligence source” language also fits comfortably within the statutory scheme as a whole, as the Court’s reading does not. I focus, at the outset, on the recent history of FOIA Exemption 1 and particularly on the way in which recent events reflect Congress’ ongoing effort to constrain agency discretion of the kind endorsed today. The scope of Exemption 1 is defined by the Executive, and its breadth therefore quite naturally fluctuates over time. For example, at the time this FOIA action was begun, Executive Order 12065, promulgated by President Carter, was in effect. That Order established three levels of secrecy — top secret, secret, and confidential — the lowest of which, “confidential,” was “applied to information, the unauthorized disclosure of which reasonably could be expected to cause identifiable damage to the national security.” 3 CFR 191 (1979).
The Order also listed categories of information that could be considered for classification, including “military plans, weapons, or operations,” “foreign government information,” and “intelligence activities [and] sources.” Id., at 193. As it is now, nondisclosure premised on Exemption 1 was subject to judicial review. A court reviewing an Agency claim to withholding under Exemption 1 was required to determine de novo whether the document was properly classified and whether it substantively met the criteria in the Executive Order. If the claim was that the document or information in it contained military plans, for example, a court was required to determine whether the document was classified, whether it in fact contained such, information and whether disclosure of the document reasonably could be expected to cause at least identifiable damage to national security. The burden was on the Agency to make this showing. At one time, this *189Court believed that the Judiciary was not qualified to undertake this task. See EPA v. Mink, 410 U. S. 73 (1973), discussed in n. 5, infra. Congress, however, disagreed, overruling both a decision of this Court and a Presidential veto to make clear that precisely this sort of judicial role is essential if the balance that Congress believed ought to be struck between disclosure and national security is to be struck in practice.5
Today’s decision enables the Agency to avoid making the showing required under the carefully crafted balance embodied in Exemption 1 and thereby thwarts Congress’ effort to limit the Agency’s discretion. The Court identifies two categories of information — the identity of individuals or entities, whether or not confidential, that contribute material related *190to Agency information gathering, and material that might enable an observer to discover the identity of such a “source” — and rules that all such information is per se subject to withholding as long as it is related to the Agency’s “intelligence function.” The Agency need not even assert that disclosure will conceivably affect national security, much less that it reasonably could be expected to cause at least identifiable damage. It need not classify the information, much less demonstrate that it has properly been classified. Similarly, no court may review whether the source had, or would have had, any interest in confidentiality, or whether disclosure of the information would have any effect on national security. No court may consider whether the information is properly classified, or whether it fits the categories of the Executive Order. By choosing to litigate under Exemption 3, and by receiving this Court’s blessing, the Agency has cleverly evaded all these carefully imposed congressional requirements.6
If the class thus freed from judicial review were carefully defined, this result conceivably could make sense. It could *191mean that Congress had decided to slice out from all the Agency’s possible documents a class of material that may always be protected, no matter what the scope of the existing executive order. But the class that the Court defines is boundless. It is difficult to conceive of anything the Central Intelligence Agency might have within its many files that might not disclose or enable an observer to discover something about where the Agency gathers information. Indeed, even newspapers and public libraries, road maps and telephone books appear to fall within the definition adopted by the Court today. The result is to cast an irrebuttable presumption of secrecy over an expansive array of information in Agency files, whether or not disclosure would be detrimental to national security, and to rid the Agency of the burden of making individualized showings of compliance with an executive order. Perhaps the Court believes all Agency documents should be susceptible to withholding in this way. But Congress, it must be recalled, expressed strong disagreement by passing, and then amending, Exemption 1. In light of the Court’s ruling, the Agency may nonetheless circumvent the procedure Congress has developed and thereby undermine this explicit effort to keep from the Agency broad and unreviewable discretion over an expansive class of information.
HH I — I
The Court today reads its own concerns into the single phrase, “intelligence source.” To justify its expansive reading of these two words in the National Security Act the Court explains that the Agency must be wary, protect itself, and not allow observers to learn either of its information resources or of the topics of its interest. “Disclosure of the subject matter of the Agency’s research efforts and inquiries may compromise the Agency’s ability to gather intelligence as much as disclosure of the identities of intelligence sources,” ante, at 176, the Court observes, and the “intelligence source” *192exemption must bear the weight of that concern as well. That the Court points to no legislator or witness before Congress who expressed a concern for protecting such information through this provision is irrelevant to the Court. That each of the examples the Court offers of material that might disclose a topic of interest, and that should not be disclosed, could be protected through other existing statutory provisions, is of no moment.7 That the public already knows all about the MKULTRA project at issue in this case, except for the names of the researchers, and therefore that the Court’s concern about disclosure of the Agency’s “topics of interest” argument is not appropriate to this case, is of no consequence. And finally, that the Agency now has virtually unlimited discretion to label certain information “secret,” in contravention of Congress’ explicit efforts to confine the Agency’s discretion both substantively and procedurally, is of no importance. Instead, simply because the Court can think of information that it believes should not be disclosed, and that might otherwise not fall within this exemption, the Court undertakes the task of interpreting the exemption to cover that information. I cannot imagine the canon of statutory construction upon which this reasoning is based.
*193Congress gave to the Agency considerable discretion to decide for itself whether the topics of its interest should remain secret, and through Exemption 1 it provided the Executive with the means to protect such information. If the Agency decides to classify the identities of nonconfidential contributors of information so as not to reveal the subject matter or kinds of interests it is pursuing, it may seek an Exemption 1 right to withhold. Under Congress’ scheme, that is properly a decision for the Executive. It is not a decision for this Court. Congress has elsewhere identified particular types of information that it believes may be withheld regardless of the existence of an executive order, such as the identities of Agency employees, or, recently, the contents of Agency operational files. See 50 U. S. C. §403g (exempting from disclosure requirements the organization, functions, names, official titles, salaries, or numbers of personnel employed by the Agency); Central Intelligence Agency Information Act, Pub. L. 98-477, § 701(a), 98 Stat. 2209, 50 U. S. C. § 431 (1982 ed., Supp. III) (exempting the Agency’s operational files from disclosure under FOIA). Each of these categorical exemptions reflects a congressional judgment that as to certain information, the public interest will always tip in favor of nondisclosure. In these cases, we have absolutely no indication that Congress has ever determined that the broad range of information that will hereinafter be enshrouded in secrecy should be inherently and necessarily confidential. Nevertheless, today the Court reaches out to substitute its own policy judgments for those of Congress.
IV
To my mind, the language and legislative history of § 102(d)(3), along with the policy concerns expressed by the Agency, support only an exemption for sources who provide information based on an implicit or explicit promise of confidentiality and information leading to disclosure of such sources. That reading of the “intelligence source” exemption poses no threat that sources will “clam up” for fear of *194exposure, while at the same time it avoids an injection into the statutory scheme of the additional concerns of the Members of this Court. The Court of Appeals, however, ordered the release of even more material than I believe should be disclosed. Accordingly, I would reverse and remand this case for reconsideration in light of what I deem to be the proper definition of the term “intelligence source.”
The Court of Appeals defined an “intelligence source” as “a person or institution that provides, has provided, or has been engaged to provide the CIA with information of a kind the Agency needs to perform its intelligence function effectively, yet could not reasonably expect to obtain without guaranteeing the confidentiality of those who provide it.” 206 U. S. App. D. C. 157, 166, 642 F. 2d 562, 571 (1980) (Sims I).
The Court today defines an “intelligence source” as one that “provides, or is engaged to provide, information . . . related to the Agency’s intelligence function,” ante, at 177, and holds also that the Director may withhold, under this definition, information that might enable an observer to discover the identity of such a source. Ante, at 178.
Indeed, these cases present a curious example of the Government’s litigation strategy. Despite the repeated urging of the District Court, the Agency steadfastly refused to invoke Exemption 1 to withhold the information at issue. The lists of names of MKULTRA researchers were in fact once classified under an Executive Order and were therefore within the potential scope of Exemption 1, but the Agency elected to declassify them. See 479 F. Supp. 84, 88 (DC 1979). The District Court went so far as to postpone the effective date of its disclosure order, so the Agency could “act on the possibility of classifying the names of institutions and researchers which would otherwise be disclosable,” ibid., and thereby withhold the information under Exemption 1. The Agency refused to do so, however.
The fact that Congress established an Agency to collect information from anywhere it could does not mean that it sought through the phrase “intelligence source” to keep secret everything the Agency did in this *188regard. Far from it, as the Court and the Agency both acknowledge, the early congressional expressions of concern about secrecy all focused on the need to maintain the anonymity of persons who would provide information only on an assurance of confidentiality.
In EPA v. Mink, 410 U. S. 73 (1973), the Court held that when an agency relied on Exemption 1, which at the time covered matters “specifically required by Executive order to be kept secret in the interest of the national defense or foreign policy,” 5 U. S. C. § 552(b)(1) (1970 ed.), a reviewing court could affirm the decision not to disclose on the basis of an agency affidavit stating that the document had been duly classified pursuant to executive order. The Court held that in camera inspection of the documents was neither authorized nor permitted because “Congress chose to follow the Executive’s determination in these matters.” 410 U. S., at 81.
Shortly thereafter, Congress overrode a Presidential veto and amended the Act with the express purpose of overuling the Mink decision. Exemption 1 was modified to exempt only matters that are “(A) specifically authorized under criteria established by an Executive order to be kept secret in the interest of national defense or foreign policy and (B) in fact properly classified pursuant to such Executive order.” 5 U. S. C. § 552(b)(1). In addition, Congress amended the judicial review language to provide that “the court shall determine the matter de novo, and may examine the contents of such agency records in camera to determine whether such records or any part thereof shall be withheld under any of the exemptions set forth in subsection (b) of this section, and the burden is on the agency to sustain its action.” 5 U. S. C. § 552(a)(4)(B). The legislative history unequivocally establishes that in camera review would often be necessary and appropriate. See S. Rep. No. 93-1200, p. 9 (1974).
The current Executive Order moves Exemption 1 a step closer to Exemption 3, given the manner in which the Court interprets the National Security Act exemption. Like its predecessor, the Order establishes three classification levels, but unlike the prior Order, the “confidential” classification no longer requires a reasonable possibility of identifiable damage. Instead, the label “confidential” now shall be applied to “information the unauthorized disclosure of which reasonably could be expected to cause damage to the national security.” Exec. Order No. 12356, 3 CFR 166 (1983). In addition, the new Order not only lists “intelligence sources” as a category subject to classification, but it also creates a presumption that such information is confidential. This presumption shifts from the Agency the burden of proving the possible consequence to national security of disclosure. As a result, if the Agency defines “intelligence source” under the Executive Order as broadly as the Court defines the term in § 102(d)(3), the Agency need make but a limited showing to a court to invoke Exemption 1 for that material. In light of this new Order, the Court’s avid concern for the national security consequences of a narrower definition of the term is quite puzzling.
For example, the Court suggests that disclosure of the fact that the Agency subscribes to an obscure but publicly available Eastern European technical journal “could thwart the Agency’s efforts to exploit its value as a source of intelligence information.” Ante, at 177; see Brief for Petitioners in No. 83-1075, p. 36. Assuming this method of obtaining information is not protected by Exemption 1, through an executive order, it would surely be protected through Exemption 3’s incorporation of § 102(d)(3) of the National Security Act. That provision, in addition to protecting “intelligence sources,” also protects “intelligence methods,” and surely encompasses covert means of obtaining information, the disclosure of which might close access to certain kinds of information. Similarly, the fact that some unsuspecting individuals provide valuable intelligence information must be protected, see ante, at 176; Brief for Petitioners in No. 83-1075, p. 39, n. 15, but again, because it is a covert means of obtaining information, not because the “source” of that information needs or expects confidentiality.