Opinion for the Court filed by Circuit Judge GINSBURG.
Dissenting Opinion filed by Circuit Judge BORK.
GINSBURG, Circuit Judge:
This case concerns the scope of the authority Congress accorded to the Secretary of State under the Immigration and Nationality Act of 1952, § 182, 8 U.S.C. § 1182(a)(27) (1982), to deny non-immigrant visas to aliens who wish to visit this country in response to invitations from United States citizens and residents to attend meetings or address audiences here. The district court, granting the government’s motion for summary judgment, held that the specific visa denials at issue were within the State Department’s statutory and constitutional authority. See Abourezk v. Reagan, 592 F.Supp. 880 (D.D.C.1984). We conclude that the district court incorrectly analyzed the statutory construction issue, and that questions of material fact remain. Accordingly, we vacate the judgment of the district court and remand the case for further proceedings consistent with this opinion.
I.
We describe first the statutory complex and, next, the essential facts of the cases presented for review.
The Immigration and Nationality Act of 1952, 8 U.S.C. § 1101 et seq. (1982) (Immigration Act or Act), delegates responsibility for regulating the entry of aliens jointly to the Attorney General, the Secretary of State, and United States consular officials abroad. The Secretary of State has the authority to revoke visas, as well as the general responsibility to supervise the issuance of visas by consular officers. See id. at § 1104; Brief for Appellees at 4. Section 1182(a) of the Act defines the categories of aliens that the government may exclude from this country. Some of these categories deal with the status of the alien, see, e.g., § 1182(a)(28) (aliens who are members of Communist or anarchist organizations); others concern the alien’s activities, see, e.g., § 1182(a)(29) (aliens likely to engage in subversion or espionage); while still others involve the procedural requirements for entry, see, e.g., § 1182(a)(20) (aliens without valid visas and passports).
Subsection (27) of section 1182(a), the provision centrally at issue in this case, directs the exclusion of an alien if the Attorney General has reason to believe that the alien “seek[s] to enter the United States solely, principally, or incidentally to engage in activities which would be prejudicial to the public interest or endanger the welfare, safety, or security of the United States.” Pursuant to State Department policy, when a consular officer abroad receives a visa request from an individual he believes may be ineligible under subsection (27), the officer forwards the request to the [360]*360State Department where the appropriate officials consider it and render binding advice. See 22 C.F.R. § 41.130(c) (1985); Brief for the Appellees at 6-9.1 If the alien is found to be within the subsection (27) classification, his exclusion is mandatory.
Subsection (28) of section 1182(a) also bears importantly on this case and was inadequately evaluated by the district court. This subsection authorizes the exclusion, inter alia, of aliens who are, or at any time have been, “members of ... the Communist Party of the United States, ... the Communist ... party ... of any foreign state, or ... any ... affiliate ... of any such ... party.” 8 U.S.C. § 1182(a)(28)(C) (1982). Unlike subsection (27), subsection (28) does not require the Secretary of State to exclude any alien who meets the stated criteria. If the Secretary recommends a wraiver of ineligibility, then, in the discretion of the Attorney General, the alien may be admitted. See 8 U.S.C. § 1182(d)(3)(A) (1982).
The McGovern Amendment, 22 U.S.C. § 2691 (1982), addresses the Secretary’s implementation of this waiver provision. The Amendment calls upon the Secretary to recommend “the approval necessary for the issuance of a visa” to “any alien who is excludible from the United States by reason of membership in or affiliation with a proscribed organization but who is otherwise admissible to the United States,” unless the Secretary certifies to the Congress that “the admission of such alien would be contrary to the security interests of the United States.” Id. at § 2691(a).
This appeal involves three actions consolidated in the district court; the actions contest the denial under subsection (27) of four visa requests. In Abourezk v. Reagan, No. 84-5673, the plaintiffs are a diverse group of United States citizens — in-eluding members of Congress, university professors, journalists, and religious leaders — who had invited Tomas Borge, the Interior Minister of Nicaragua, to speak to them in this country. See Brief of Plaintiffs-Appellants at 9-11. The Nicaraguan government applied to the United States Embassy in Managua for a non-immigrant visa for Borge. After obtaining an advisory opinion from the State Department, the consular officer informed Borge, in late November 1983, that his visa request had been denied pursuant to section 1182(a)(27) of the Immigration Act. See Brief for the Appellees at 9-11.
The plaintiffs in Cronin v. Shultz, No. 84-5708, are principally groups interested in nuclear disarmament who had invited Nino Pasti to attend and speak at a rally in Boston. Pasti is a former member of the Italian Senate and former general in the Italian armed forces; he is now a peace activist. See Brief of Plaintiffs-Appellants at 8. Pasti is also a participant in the World Peace Council, an organization which the State Department believes to be controlled by the Soviet Communist Party. See World Peace Council: Instrument of Soviet Foreign Policy, Foreign Affairs Note (Department of State, April 1982), reprinted in Joint Appendix at 144-48. The consular officer in Rome found Pasti ineligible to receive a visa under subsection (28). The officer therefore requested an advisory opinion from the State Department on the possibility of a waiver. In response, the Department informed the officer that Pasti was ineligible under subsection (27). The consular officer thereupon notified Pasti, in mid-October 1983, that his visa request had been denied. See Affidavit of Louis P. Goelz, reprinted in Joint Appendix at 163-64.
In City of New York v. Shultz, No. 84-5681, the plaintiffs, the New York City [361]*361Commission on the Status of Women and several women’s studies programs at various universities, had extended speaking invitations to two Cuban women, Olga Finlay and Leonor Rodriguez Lezcano; these individuals have special expertise regarding the status of women and family law in Cuba. See Brief of Plaintiffs-Appellants at 13-14. According to the State Department, both women are members of the Federation of Cuban Women, an organization affiliated with the Communist Party of Cuba. See Affidavit of Louis P. Goelz, reprinted in Joint Appendix at 164-65. Visa applications for the two women were conveyed by diplomatic note from the Government of Cuba. The consular officer in Havana forwarded the visa requests to the State Department and was advised that Finlay and Lezcano were ineligible under subsection (27). He notified them, in early October 1983, that their visa requests had been denied. See Brief for the Appellees at 12-13.2
The plaintiffs filed suit in the district court requesting injunctive and declaratory relief. They argued that the State Department’s exclusion of the aliens invited by plaintiffs to speak here exceeded the Department’s statutory authority under subsection (27) and violated the plaintiffs’ first amendment right to engage in dialogue with these foreign individuals. The district court granted the defendants’ request for a stay of discovery pending their filing of a motion for summary judgment. See Abourezk v. Reagan, No. 83-3739 (D.D.C. Feb. 8, 1984) (order granting motion for extension of time and protective order staying discovery). After consideration of both the public documents and three classified affidavits submitted by the government for the court’s in camera inspection, the district judge granted the defendants’ motion for summary judgment. The court held that the government’s action was within its statutory authority and survived the very limited constitutional scrutiny appropriate in a case concerning the admission or exclusion of aliens. See Abourezk v. Reagan, 592 F.Supp. 880 (D.D.C.1984).
II.
The government raises several preliminary objections to the adjudication of these [362]*362claims. The State Department suggests that the district court lacked jurisdiction over the subject matter, that the plaintiffs have no right to contest the visa denials on statutory grounds, and that the case is moot. We find these contentions insubstantial.
The district court had subject matter competence in this case under both its general federal question jurisdiction, see 28 U.S.C. § 1331 (1982), and its specific jurisdiction over claims arising under the Immigration and Nationality Act, see 8 U.S.C. § 1329 (1982). Section 1329 states that “[t]he district courts ... shall have jurisdiction of all causes, civil and criminal, arising under any of the provisions of this sub-chapter [of the Immigration Act].” Section 1182(a)(27) is part-of the relevant subchapter. The courts have reasonably inferred from this broad grant of jurisdiction that “clear and convincing evidence” of a congressional intent to preclude judicial review is lacking. See Abbott Laboratories v. Gardner, 387 U.S. 136, 141, 87 S.Ct. 1507, 1511, 18 L.Ed.2d 681 (1967) (stating, as the general rule, presumption in favor of judicial review of final agency action, absent “clear and convincing evidence” of congressional intent to the contrary); see, e.g., Karmali v. Immigration and Naturalization Service, 707 F.2d 408, 409-10 (9th Cir.1983) (interpreting § 1329 as grant of jurisdiction over Immigration Act claims); Acosta v. Gaffney, 558 F.2d 1153, 1156 (3d Cir.1977) (same).
We further note, as did the district court, see Abourezk, 592 F.Supp. at 883 n. 10, the Supreme Court’s disposition on the merits in Kleindienst v. Mandel, 408 U.S. 753, 92 S.Ct. 2576, 33 L.Ed.2d 683 (1972). In that case, United States sponsors of a Belgian journalist objected to his exclusion under section 1182(a)(28). Presumably, had the Court harbored doubts concerning federal court subject matter jurisdiction in Mandel, it would have raised the issue on its own motion. See, e.g., Louisville & Nashville R.R. v. Mottley, 211 U.S. 149, 152, 29 S.Ct. 42, 43, 53 L.Ed. 126 (1908).
The government also argues that the plaintiffs’ statutory pleas may not be entertained; this argument blends objections to plaintiffs’ standing and to their ability to state a claim for relief (cause of action). The Immigration Act, we agree, does not itself endow plaintiffs with a right of action.3 But the Administrative Procedure Act, 5 U.S.C. § 701 et seq. (1982) (APA), which complements statutes controlling agency behavior, does. Section 702 of that Act, as explained by the Supreme Court in Association of Data Processing Service Organizations v. Camp, 397 U.S. 150, 152-53, 90 S.Ct. 827, 829-30, 25 L.Ed.2d 184 (1970), authorizes suit by persons who suffer “injury in fact” by reason of the challenged agency action and are “arguably within the zone of interests to be protected or regulated” under a relevant statute.4
Persons who are not materially affected by an agency’s interpretation of the governing, law may not successfully invoke the APA to achieve court review'. See, e.g., Capital Legal Foundation v. Commodity Credit Corporation, 711 F.2d 253, 259-60 (D.C.Cir.1983). But the plaintiffs in this case are hardly strangers to the matter at issue. Unquestionably, they are “aggrieved” by the State Department’s resort to section 1182(a)(27) to keep out people they [363]*363have invited to engage in open discourse with them within the United States. See Brief for the Appellees at 20 (“Refusing visas to their alien invitees undoubtedly inhibits plaintiffs’ rights to communicate with these individuals in face-to-face discussions on American soil.”). The plaintiffs are substantively interested in, and adversely affected by, the Department’s interpretation of subsection (27) as it coexists with subsection (28). They are, as the district court observed, at least arguably within the zone regulated by the statute. See Abourezk, 592 F.Supp. at 884 n. 10.5 They therefore have a cognizable stake in the construction of subsections (27) and (28), a practical interest adequate under section 702 of the APA to secure judicial review of their pleas regarding those provisions. Cf. Capital Legal Foundation, 711 F.2d at 259-60 & n. 17.
Section 701 of the APA states that “[tjhis chapter applies, according to the provisions thereof, except to the extent that — (1) statutes preclude judicial review; or (2) agency action is committed to agency discretion by law.” 5 U.S.C. § 701 (1982). As discussed above, the Immigration Act, far from precluding review, affirmatively provides for it. See supra at 1049-50.6 Furthermore, the statute does not commit to unguided agency discretion the decision to exclude an alien. The Supreme Court has recently interpreted the “committed to unfettered agency discretion” provision as applicable only “if the statute is drawn so that a court would have no meaningful standard against which to judge the agency’s exercise of discretion.” Heckler v. Chaney, — U.S. -, 105 S.Ct. 1649, 1655, 84 L.Ed.2d 714 (1985). Under this interpretation, the Immigration Act emphatically did not commit the decision to exclude an alien to standardless agency discretion; the statute lists thirty-three distinctly delineated categories that conspicuously provide standards to guide the Executive in its exercise of the exclusion power. See 8 U.S.C. § 1182(a) (1982). The statutory language thus channels the Secretary of State’s discretion and, under Heckler v. Chaney, the constraints Congress imposed are judicially enforceable.
In sum, the APA applies to the plaintiffs’ challenges; that Act gives them a right of review extending to the statutory as well as the constitutional propriety of the State Department’s application of section 1182(a)(27) to exclude the aliens invited by plaintiffs to the United States as speakers and meeting participants. We add, fi[364]*364nally, that in the special circumstances of this case, the court has an independent obligation to consider questions of statutory construction. We should so proceed in order to avoid a constitutional confrontation, if it is possible for us to stop short of that point. See Ashwander v. TVA, 297 U.S. 288, 347, 56 S.Ct. 466, 483, 80 L.Ed. 688 (1936) (Brandéis, J., concurring). This consideration strongly supports our attention to the plaintiffs’ nonconstitutional arguments. We should not reach “[the] constitutional question although properly presented by the record, if there is also present [a statutory construction] ground upon which the case may be disposed of.” Id. In rejecting the government’s demand that we confine review to the consistency of the State Department’s actions with the Constitution, we thus observe the “cardinal principle” directing a court first to inquire “whether a construction of the statute is fairly possible by which the [constitutional] question may be avoided.” Id. at 348, 56 S.Ct. at 483 (quoting Crowell v. Benson, 285 U.S. 22, 62, 52 S.Ct. 285, 296, 76 L.Ed 598 (1932)).
Turning to the last of the government’s threshold objections, we hold that the case is not moot. The government asserts that the State Department considers each visa application independently and that the present denials in no way bear on the results of any future application that the excluded aliens might make. See Brief for the Appellees at 26 n. 23; Affidavit of Louis P. Goelz, reprinted in Joint Appendix at 158. However, the reasons for the visa denials offered by the State Department and accepted by the district court indicate that the prospect of future denials of applications by these aliens is a genuine, and not merely a “theoretical[,] possibility.” Murphy v. Hunt, 455 U.S. 478, 482, 102 S.Ct. 1181, 1183, 71 L.Ed.2d 353 (1982).
The State Department’s dominant reasons for the denials that sparked this litigation do not refer to a particular event in the world whose cessation might induce the government to grant visa requests from the aliens whom plaintiffs invited to speak. Instead, the Department cites the continuing status of these aliens as members of organizations or governments hostile to the United States.7 The aliens, whose affiliations apparently have not changed, assert that their interest in entering the United States continues, and the plaintiffs have represented that they still wish to invite these aliens to speak in this country. See Brief of Plaintiffs-Appellants at 9 (Pasti), 13 (Borge), 17 (Finlay and Lezcano). In light of the reasons for the visa denials tendered by the government and relied upon by the district court, these allegations of continuing interest suffice to establish a genuine prospect that the plaintiffs will suffer the same injury in the future. See Nebraska Press Association v. Stuart, 427 U.S. 539, 546-47, 96 S.Ct. 2791, 2796-97, 49 L.Ed.2d 683 (1976).8 We therefore reach the merits of the plaintiffs’ claims.
[365]*365III.
The plaintiffs raise three issues of statutory interpretation. They argue, first, that subsection (27) does not authorize exclusion on the basis of foreign policy concerns, as opposed to issues of “public interest or ... [national] welfare, safety, or security.... ” 8 U.S.C. § 1182(a)(27) (1982). Second, the plaintiffs contend that subsection (27) allows exclusion only if it appears that the alien’s activities in the United States would endanger the public welfare and not if his or her mere presence or entry might do so. And, third, the plaintiffs suggest that the government’s interpretation of subsection (27) violates the statute because it renders subsection (28) superfluous and undermines the restrictions Congress has placed on the Executive’s use of subsection (28). See McGovern Amendment, 22 U.S.C. § 2691 (1982).
Our approach to statutory interpretation is informed by the guidelines the Supreme Court announced in Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984). According to Chevron, a court must first examine the statutory provision in question to determine whether Congress had a specific intent with respect to the issue at hand. See id. 104 S.Ct at 2781. This examination should begin with the language of the statute, see Consumer Product Safety Commission v. GTE Sylvania, Inc., 447 U.S. 102, 108, 100 S.Ct. 2051, 2056, 64 L.Ed.2d 766 (1980), but the court may also inspect legislative history and past administrative practice for any light these sources may shed on congressional intent. See, e.g., Chevron, 104 S.Ct. at 2791-92; Rettig v. Pension Benefit Guaranty Corporation, 744 F.2d 133,144-50 (D.C.Cir.1984). If the court finds that Congress had a specific intent with respect to the issue, the court stops there and enforces that intent regardless of the agency’s interpretation. See Chevron, 104 S.Ct. at 2781-82 & n. 9. If, however,the court finds that Congress had no specific intent, the agency’s interpretation should be accorded great deference and invalidated only if it is not a “reasonable accommodation of conflicting policies that were committed to the agency’s care by the statute____” Chevron, 104 S.Ct. at 2783 (quoting United States v. Shimer, 367 U.S. 374, 382-83, 81 S.Ct. 1554, 1560, 6 L.Ed.2d 908 (1961)).
Following these guidelines, we conclude, in agreement with the government and the district court, see Abourezk, 592 F.Supp. at 885-86, that Congress intended foreign policy concerns to rank among the national interests whose protection would justify exclusion of an alien under subsection (27). The broad language of (27) evinces no intent to restrict the kinds' of governmental concerns that would qualify; the subsection speaks of “public interest^] ... welfare, safety, or security” and places no limitation on these encompassing terms. Only an isolationist view patently inconsistent with the reality of our late twem -‘th century world could account for a belief that the “public interest” and the “national welfare” were not dependent, in part, on the effective execution of our foreign policy. The court surely should not adopt on its own initiative such a counter-intuitive interpretation of expansive statutory language, and the plaintiffs have identified nothing in the legislative history or administrative practice to suggest that Congress intended to exclude foreifen policy concerns from consideration under subsection (27). Because the State Department’s interpretation appears fully consistent with congressional intent, we need take this inquiry no further.
The plaintiffs also contend that subsection (27) explicitly authorizes exclusion based only on “activities” in which the alien may be expected to “engage” and not on mere entry or presence. The district court decided this issue for the government. See Abourezk, 592 F.Supp. at 884-85. We conclude that it did so on an inadequate record. We therefore remand for a [366]*366fuller airing of the activity/mere entry question.
The language of the statute, as the Dissent acknowledges, supports the plaintiffs’ interpretation on this issue. Dissent at 9. The provision does not say “persons whose presence in this country would be prejudicial to the interests of the United States are barred from entry.” Rather, subsection (27) makes ineligible for a visa those aliens who “seek to enter the United States solely, principally, or incidentally to engage in activities which would be prejudicial” to United States interests. The specific reference to activities would be superfluous, indeed, misleading, if entry or presence alone could justify exclusion. A familiar canon of statutory construction cautions the court to avoid interpreting a statute in such a way as to make part of it meaningless. See 2A N. Singer, Sutherland Statutory Construction § 46.06 (4th ed.1984). This basic guide and the plain thrust of the language of subsection (27), we emphasize, weigh heavily against thé government’s reading.
The terms Congress employed in other subsections on, exclusion are also consistent with plaintiffs’ interpretation. Section 1182(a) sets out thirty-three separate categories of excludable aliens; this enumeration demonstrates that Congress could and did clearly distinguish status-based categories from conduct-based categories. See supra at 1047. Congress’ undoubted ability to draft categories based only on status, when that is the legislature’s intention, strengthens the inference that the words “to engage in activities” contained in subsection (27) were not put there inadvertently.
The legislative history on this issue, however, is not a prop upon which plaintiffs can rely. It is terse and tugs in more than one direction. The language of section 1182(a)(27) of the 1952 Immigration Act was taken almost verbatim from section 22 of the Internal Security Act of 1950, 64 Stat. 987,1006 (repealed 1952). The Senate Reports on section 22 seem to assume that both existing law and the proposed section allowed exclusion when the very entry of the alien would be prejudicial to the public interest.9 The Conference Committee Report, on the other hand, implies that existing law and section 22 authorize exclusion only on the basis of activities.10
Given the inconclusive state of the legislative history,11 evidence of con[367]*367gressional acquiescence (or the lack thereof) in an administrative construction of the statutory language during the thirty-four years since the current act was passed could be telling. Information about such acquiescence, or the absence of it, would rank as a significant indicator of the legislature’s will. See Zemel v. Rusk, 381 U.S. 1, 8-12, 85 S.Ct. 1271, 1276-1279, 14 L.Ed.2d 179 (1965).12 Unfortunately, evidence on this point was thin when the district court determined to accept the State Department’s interpretation, for that court had stayed discovery pending the government’s motion to dismiss. See Abourezk v. Reagan, No. 83-3739 (D.D.C. Feb. 8, 1984). The only evidence of administrative practice now in the record consists of conflicting assertions in the affidavits of past and present State Department officials and a sparse collection of illustrations. Compare Affidavit of Louis P. Goelz, reprinted in Joint Appendix at 159-60 (present Deputy Assistant Secretary of State), with Affidavit of Leonard C. Meeker, reprinted in Joint Appendix at 252 (former Legal Adviser to the Department of State).
The illustrations — advanced by the State Department as indicative of an administrative practice of excluding aliens under subsection (27) based on entry or' presence alone — include descriptions of three actual visa denials and four examples listed in the State Department Manual. While these illustrations provide some support for the government’s position, they are inadequate to enable a court to determine reliably the nature of the general administrative practice under subsection (27).
The Manual offers the following examples of aliens whose visa applications might properly be denied under (27): an alien who might engage in conspiratorial activity against the United States while in the country; an alien who is known to be a member of a terrorist organization; an alien who is associated with a criminal organization; and an alien official who engaged in physical brutality while in power or was associated with a regime that did so. See Brief of Plaintiffs-Appellants at 37 (citing Foreign Affairs Manual, Pt. II, § 41.91(a)(27), reprinted in 6 C. Gordon & H. Rosenfeld. Immigration Law and Procedure 32-214.18 (1985)). Although the first three examples may be explained in terms of the aliens’ probable activity in the United States, the last example, the government argues, embodies the State Department’s longstanding view that exclusion under subsection (27) is appropriate when the mere entry of the alien would prejudice foreign policy objectives. In that example, the government is concerned, not about the possibility that the official might engage in physical brutality while in the United States, but about the impact of the very admission of such a person on our foreign policy interests. See Brief for the Appellees at 56 n. 42. This fourth example in the Manual may represent an open assertion of the power to exclude under subsection (27) on the basis of entry alone; such an assertion of authority may warrant the implication of an executive policy, even if the policy is only infrequently applied, and may contribute^ to a [368]*368showing of congressional acquiescence in that policy. See Haig v. Agee, 453 U.S. 280, 303, 101 S.Ct. 2766, 2780, 69 L.Ed.2d 640 (1981).
The State Department also offers three instances of actual visa denials that were allegedly based on entry rather than activity and were reported to various members of Congress and committees. In two of the cases the reasons for denial included references to the alien’s anticipated activities in the United States. See Second Affidavit of Louis P. Goelz, reprinted in Joint Appendix at 306, 308.13 In the third case, however, the State Department appears to have applied the fourth example in the Manual: in that case, former Nazi SS officer Otto Skorzeny was denied a visa under subsection (27) for foreign policy reasons. See id. at 306. Thus, there seems to be at least one instance, of which Congress was apprised, in which the State Department actually applied the interpretation of subsection (27) that the government presses in this litigation.
This meager evidence does not demonstrate the kind of consistent administrative interpretation necessary to give rise to a presumption of congressional acquiescence. See Kent v. Dulles, 357 U.S. 116, 128, 78 S.Ct. 1113, 1119, 2 L.Ed.2d 1204 (1958) (holding that “scattered rulings ... not consistently of one pattern” are an insufficient basis on which to impute congressional intent). The examples cited by the State Department, in conjunction with the inconclusive legislative history, however, do cast some doubt on the plaintiffs’ interpretation, an interpretation that otherwise seems indicated by the language of the statute. In order to weigh the relative persuasiveness of the two interpretations, the district court needed more information.14 It should have asked the government to come forward with further examples of the exercise or assertion of power to exclude under subsection (27) on the basis of presence alone; and, in fairness, it should have allowed the plaintiffs sufficient discovery to contest those examples and provide counter-examples.15
Without thus developing a more substantia] record, the district court could not make a secure finding concerning the nature of the administrative practice under subsection (27). And without such a finding, given the inconclusive state of the legislative history and the strength of the plaintiffs’ textual argument, the district court’s decision in favor of the government’s interpretation was premature. We therefore set aside the district court's holding on this issue and remand for the fuller proceedings appropriate prior to resolution of this question of statutory interpretation.
The plaintiffs also contend that the government’s interpretation of subsection (27) violates the statute because it effectively swallows up subsection (28) and [369]*369thereby nullifies the restrictions placed by the McGovern Amendment on the use of the latter subsection. We find this argument persuasive. The Executive may not use subsection (27) to evade the limitations Congress appended to subsection (28).
The McGovern Amendment calls upon the Secretary of State to recommend a waiver of ineligibility, and thereby open the way for admission of an alien who belongs to a subsection (28) organization, unless the Secretary certifies to the Congress that admission of the alien would “be contrary to the security interests of the United States....” 22 U.S.C. § 2691(a) (1982). The district judge in this case found that prejudice to foreign policy did not qualify as a “security interest” within the meaning of the McGovern Amendment. See Abourezk, 592 F.Supp. at 855; accord Allende v. Shultz, 605 F.Supp. 1220,1225 n.2 (D.Mass. April 2,1985). The State Department itself appears to have reached the same conclusion. See Brief of Plaintiffs-Appellants, app. B at 2 (letter from Alvin Paul Drischler, Acting Assistant Secretary of State, to George Bush, President of the United States Senate (Oct. 18, 1983)) (“The result [of the McGovern Amendment] has been that the Secretary of State is effectively precluded from acting in such cases on the basis of legitimate foreign policy factors and considerations.”).
If the government could use subsection (27) to exclude aliens whose entry might threaten our foreign policy objectives simply because of their membership in Communist organizations, then subsection (28) would be made superfluous and the congressional will expressed in the McGovern Amendment would be nullified. Conversely, the restrictions on subsection (28) must not be read in a fashion that would rob subsection (27) of its independent scope and meaning. To preserve the significance of both sections, and the congressional intent that guided their adoption, the two sections must not be homogenized or treated as interchangeable parts. See Weinberger v. Hynson, Westcott & Dunning, Inc., 412 U.S. 609, 633, 93 S.Ct. 2469, 2485, 37 L.Ed.2d 207 (1973) (holding that courts must interpret statutes in such a way as to give effect to all of their provisions).16
The government argues that it has distinguished the two sections by using (27) only when it has a reason for exclusion in addition to the alien’s membership in an organization listed in (28). See Transcript of Proceedings at 38-40, Abourezk v. Reagan, No. 84-5673 (D.C.Cir.Sept. 23, 1985). This standard, however, is inadequate to prevent subsection (27) from overwhelming and obliterating subsection (28) and the McGovern Amendment. A reason that is in addition to the fact of membership but not independent of that fact provides an insufficient bulwark against the possibility of Executive evasion of the will of Congress as expressed in the McGovern Amendment.
For example, the broadest generalization about the character or activities of members of a group would be a reason in addition to the bare fact that a particular alien belonged to that group. But to exclude an alien based on the perceived bent or proclivities of members of a subsection (28) organization would contravene the core purpose of the McGovern Amendment. The Amendment was intended to implement the United States’ promise under the [370]*370Helsinki Accords17 to promote the free flow of people and ideas across national borders. See 22 U.S.C. § 2691(a) (1982); S. Rep. No. 194, 95th Cong., 1st Sess. 13 (1977), U.S.Code Cong. & Admin.News 1977, pp. 1625, 1635. The Amendment fulfills that commitment by assuring that a would-be speaker is not condemned by association with a subsection (28) organization 18 if he is “otherwise admissible.” 22 U.S.C. § 2691(a) (1982). A visa denial based on a generalization about the members of a subsection (28) group surely qualifies as the brand of guilt by association Congress sought to check. No reason particular to this alien or to this moment in time distinguishes such a denial; the denial is appropriate for all members at all times because it is simply a condemnation of the group as a whole.19
We hold that when an alien is a member of a proscribed organization, so that subsection (28) applies, the government may bypass that provision and proceed under subsection (27) only if the reason for the threat to the “public interest[,] ... welfare, safety, or security” is independent of the fact of membership in or affiliation with the proscribed organization. Only if such an independent reason exists will the use of subsection (27) leave intact the congressionally mandated restrictions on subsection (28).20
[371]*371The Dissent finds sufficient reason, separate from the applicants’ membership in proscribed organizations, for upholding the government’s action under subsection (27). This reason consists of alleged affiliations of the visa applicants with particular governments hostile to the United States (the governments of Nicaragua, the Soviet Union, and Cuba). See Dissent at 1069-71. We do not reject affiliation with a particular foreign government as beyond the pale of subsection (27). However, if the alleged government affiliation is presumed because of the applicant’s membership or participation in a subsection (28) organization, we would not count that presumption as independent of the organizational tie. In other words, if all members of a proscribed organization were automatically branded “affiliates” of a certain government, that branding would be no more independent of the fact of membership than the generalization about the character or activities of group members to which we earlier referred. See supra at 1057-58.21 On the other hand, if the State Department pinpoints the alien’s official post, or action as an official representative of a hostile government as the reason for the exclusion under subsection (27) on foreign policy grounds, then the “independent of” organizational membership standard would be met.22
The State Department, however, has so far obscured its position. It mentioned both subsection (28) organizational affiliations and connections between the visa applicants and certain foreign governments. See, e.g., Affidavit of Louis P. Goelz, reprinted, in Joint Appendix at 162-65. But at the same time, the Department volunteered that earlier in the same year (1983), during Borge’s incumbency as Interior Minister of Nicaragua, a visa application for his travel to the United States had been approved. Id. at 166. Similarly, the Department represented that both Finlay and Pasti “have previously received [non-immigrant visas] and travelled to the United States.” Id. In short, the Department [372]*372has never squarely advanced as the rationale for exclusion the applicants’ government ties rather than their subsection (28) organization membership.23 Instead, it has taken an “either/or” stance. See Abourezk, 592 F.Supp. at 888 {in camera affidavits show that applicants were denied entry “because of their personal status as officials of governments or organizations which are hostile to the United States”) (emphasis supplied).
If we were to deem it sufficient, as the Dissent does, for the State Department so to rest on pleas in the alternative, we would shirk our obligation to enforce the congressional direction, which the Dissent acknowledges, see Dissent at 14, to pay genuine heed to the McGovern Amendment. The Department, as the agency charged by Congress with the administration of the statute, of course would retain authority initially to frame criteria for determining when a sufficiently independent reason exists to warrant invocation of subsection (27). The Department’s criteria must be clear enough to allow the courts to fulfill their responsibility to insure that the executive authority respects congressional intent, but the precise contours of the “independence inquiry” should be left, in the first instance, to the sound and expert judgment of the State Department. We therefore remand the three consolidated cases so that both the district court and the government may reevaluate these visa denials without the statutory misinterpretation that casts doubt on their previous analyses.24
IV.
We note our grave concern about the district court’s heavy reliance upon in camera ex parte evidence when it granted the defendants’ motion for summary judgment. That court evaluated the public documentation as “entirely conclusory” and inadequate; it thereupon turned to the classified affidavits and asserted that it found in them information justifying its final disposition. See Abourezk, 592 F.Supp. at 886-87. We caution the district court, in the further proceedings this opinion requires, to make certain that plaintiffs are accorded access to the decisive evidence to the fullest extent possible, without jeopardizing legitimately raised national security interests.
It is a hallmark of our adversary system that we safeguard party access to the evidence tendered in support of a requested court judgment. The openness of judicial proceedings serves to preserve both the appearance and the reality of fairness in the adjudications of United States [373]*373courts. It is therefore the firmly held main rule that a court may not dispose of the merits of a case on the basis of ex parte, in camera submissions. See In re Application of Eisenberg, 654 F.2d 1107, 1112 (5th Cir.1981).
Exceptions to the main rule are both few and tightly contained. Most notably, inspection of materials by a judge isolated in chambers may occur when a party seeks to prevent use of the materials in the litigation. When one side, seeking to block consideration of relevant matter, asserts an evidentiary privilege, the court may inspect the evidence in camera and alone for the limited purpose of determining whether the asserted privilege is genuinely applicable. See id. If the court finds that the claimed privilege does not apply, then the other side must be given access to the information; if the court’s finding is that the privilege does apply, then the court may not rely upon the information in reaching its judgment. See Ellsberg v. Mitchell, 709 F.2d 51, 64 (D.C. Cir.1983), cert. denied sub nom. Russo v. Mitchell, 465 U.S. 1038, 104 S.Ct. 1316, 79 L.Ed.2d 712 (1984). In either case, no party will be faced — as were the plaintiffs in this case — with a decision against him based on evidence he was never permitted to see and to rebut.
Only in the most extraordinary circumstances does our precedent countenance court reliance upon ex parte evidence to decide the merits of a dispute. Our one case in point, Molerio v. Federal Bureau of Investigation, 749 F.2d 815 (D.C.Cir. 1984), involved the state secrets privilege, a privilege not invoked in this case. The government pressed acute national security concerns in Molerio, and we recognized a large risk that an unjust result would eventuate if the case proceeded without the privileged material. See id. at 825. While we allowed court recourse to the confidential information in Molerio, we based that allowance upon proper invocation of the privilege; a demonstration of compelling national security concerns; and public disclosure by the government, prior to any in camera examination, of as much of the material as it could divulge without compromising the privilege. In addition, the plaintiff in Molerio had been accorded considerable discovery of non-privileged materials. See id. at 819; see also Ellsberg, 709 F.2d at 63-64.
We mention finally a third class of cases in which in camera inspection may occur: exceptions to the main rule specified by statute. The prime current example is the Freedom of Information Act, 5 U.S.C. § 552 (1982). Even in administering such legislation, however, we have been vigilant to confine to a narrow path submissions not in accord with our general mode of open proceedings. See, e.g., Vaughn v. Rosen, 484 F.2d 820, 827-28 (D.C.Cir.1973), cert. denied, 415 U.S. 977, 94 S.Ct. 1564, 39 L.Ed.2d 873 (1974) (requiring the government to create a public index listing privileged documents and providing explanations of the claim of privilege). No statutory scheme permitting closeted inspection of evidence is implicated in this case.
In sum, we expect the district court, on remand, to be mindful of the tight boundaries set in Molerio and of the overriding importance of assuring plaintiffs’ receipt of the most complete information and explanation permissible.
V.
The Executive has broad discretion over the admission and exclu'-’on of aliens, but that discretion is not boundless. It extends only as far as the statutory authority conferred by Congress and may not transgress constitutional limitations. It is the duty of the courts, in cases properly before them, to say where those statutory and constitutional boundaries lie.
Congress, in the legislation at issue, has specified categories of excludable aliens and has qualified the application of one of those categories through the passage of the McGovern Amendment. The State Department must respect the restraints Congress imposed. The district court’s conclusion that the congressionally prescribed boundaries had not been transgressed was insufficiently grounded; the court proceed[374]*374ed to judgment without the exploration of administrative practice necessary to an informed decision and it did not adequately advert to the relationship between two statutory provisions. We therefore vacate the district court’s judgment. We remand the three consolidated cases for reexamination of the visa denials in question to insure that the challenged government action is within the statutory and constitutional authority of the State Department.
Judgment vacated and cases remanded for proceedings consistent with this opinion.