in an opinion joined by Circuit Judges LEYENTHAL and SPOTTSWOOD W. ROBINSON, III, and by Chief Judge BAZELON except as to Part III — B, concerning which he filed a dissenting opinion, concluded that:
1. In Bivens v. Six Unknown Named Agents of the Federal Bureau of Narcotics, 403 U.S. 388, 91 S.Ct. 1999, 29 L.Ed.2d 619 (1971), the Supreme Court held that a federal cause of action for damages exists to remedy violations of the Fourth Amendment. The warrant-less surveillance conducted by appellees constitutes such a Fourth Amendment violation. Infra, 170 U.S.App.D.C. at ---, 516 F.2d at 611-654.
(a) Although Presidents since the time of Franklin Roosevelt have authorized warrantless national security surveillance, the practice does not justify dispensing with the warrant requirement. Since the practice developed at a time when there were no Fourth Amendment restrictions on non-trespassory surveillance, we cannot view it as an affirmative declaration by prior Presidents that their surveillance activities were immune from constitutional strictures. In any event, an unconstitutional practice, no matter how inveterate, cannot be condoned by the judiciary. Infra, 170 U.S. App.D.C. at---, 516 F.2d at 616— 620.
(b) Prior Supreme Court decisions concerning the broad plenary powers of the President in the field of foreign af-. fairs do not predetermine the proper accommodation of presidential powers with the mandate of the Fourth Amendment and do not require that the President’s national security surveillance orders be either exempted from any judicial review or exempted from prior judicial scrutiny. Although these cases indicate that the President’s power to obtain foreign intelligence information is vast, they do not suggest that he is immune from constitutional requirements; the procedural question of how the President may constitutionally exercise his powers remains even though those substantive powers are found to exist. Infra., 170 U.S.App.D.C. at---, 516 F.2d at 616-627.
(c) Both appellees in this case and some other courts facing the question of warrantless national security surveillance have asserted that, since “reasonableness” is the ultimate test under the Fourth Amendment, the reasonableness of such warrantless surveillance is to be determined on the circumstances of the particular case. However, this approach is inconsistent with the methodology the Supreme Court has consistently followed when addressing Fourth Amendment problems: absent special circumstances, a warrantless search is per se unlawful. As the Keith decision indicates, a court must ask more than whether there is a legitimate presidential need to conduct electronic surveillance; it must also ask whether a warrant, which places a neutral and detached magistrate or judge between investigative or prosecutorial officials of the Executive Branch and the First and Fourth Amendment rights of our citizens, should be obtained before doing so. This requires an analysis of whether a warrant would frustrate the legitimate governmental goal in the category of cases of which this is but one example. Infra, 170 U.S.App.D.C. at ---, 516 F.2d at 627-633.
(d) In balancing individual rights and governmental needs in the intelligence gathering area, it is clear that pri- or judicial review can prevent Executive abuses and safeguard not only the Fourth Amendment right of privacy, but also the First Amendment values of freedom of speech and association. Thus prior judicial review should be required unless it will frustrate the legitimate goals of surveillance. A search of prior cases upholding the President’s asserted *602right to conduct warrantless foreign security surveillance reveals almost a total lack of reasons for not requiring a warrant. Nevertheless, possible factors that might dictate abrogation of the warrant requirement include (1) lack of judicial competence to deal with foreign affairs data; (2) danger of security leaks which might endanger the lives of informants and agents and which might seriously harm national security; (3) the fact that such surveillance is not being used for criminal prosecutions, but only for “strategic” intelligence gathering; (4) the possibility that the delay involved in the warrant procedure might result in substantial harm to national security; and (5) the fact that the administrative burden on the courts or the Executive Branch which would result from such a requirement would be enormous. Our analysis of these factors indicates that none is persuasive as a reason for abrogating the warrant procedure when the President seeks to obtain information that affects foreign affairs. Infra, 170 U.S.App.D.C. at---, 516 F.2d at 633-652.
(e) Although the above analysis suggests that, except for situations where exigent circumstances are present, there should be no category of surveillance for which the President need not obtain a warrant, our holding today does not sweep that broadly. We only hold in this case that, even where foreign affairs are involved, the President must obtain a warrant when the domestic organization which is the subject of the surveillance is neither an agent of nor acting in collaboration with the foreign power posing the national security threat. This holding is particularly reinforced by the rationale and approach of the Keith decision. Infra, 170 U.S.App.D.C. at---, 516 F.2d at 650-655.
(f) Since judges will be forced to decide whether “probable cause” to install national security wiretaps exists, we offer some guidance on the factors which judges should consider in issuing warrants. These include the importance of the information sought by the Government, the availability of less intrusive means for obtaining the information, and the degree to which surveillance of a particular scope and duration will infringe individual rights. Infra, 170 U.S. App.D.C. at---, 516 F.2d at 655— 659.
2. Congress intended that the procedures and remedies of Title III of the Omnibus Crime Control and Safe Streets Act of 1968 would apply to all surveillance which must, under the Constitution, be conducted pursuant to a warrant procedure. Since we' hold that a warrant is constitutionally required under the circumstances of this case, appellants are entitled to the liquidated damages recovery provided in that Act, unless appellees on remand establish an affirmative defense of good faith. Infra, 170 U.S.App.D.C. at---, 516 F.2<f at 659-673.
(a) The dictum in Keith concerning possible future congressional legislation in the national security area is consistent with our holding that Congress intended Title III to be as comprehensive as possible, covering all surveillance which the Constitution dictates must be conducted only after securing judicial approval. This statutory construction is supported by the language of Title III, by its legislative history, by- the fate of proposed wiretap legislation over the past 20 years, and by various policy considerations. Infra, 170 U.S.App.D.C. at ---, 516 F.2d at 659-670.
(b) Appellees may on remand, however, avoid damages on both constitutional and statutory grounds if they can establish (1) that they had a subjective good faith belief that it was constitutional to install warrantless wiretaps under the circumstances of this case, and (2) that this belief was itself reasonable. Infra, 170 U.S.App.D.C. at---, 516 F.2d at 670-673.