Mr. Justice Brennan
announced the judgment of the Court and an opinion in which Mr. Justice White, Mr. Justice Marshall, and Mr. Justice Blackmun join.
Community antenna television (CATV) was developed long after the enactment of the Communications Act of 1934, 48 Stat. 1064, as amended, 47 U. S. C. § 151 et seq., as an auxiliary to broadcasting through the retransmission by wire of intercepted television signals to viewers otherwise unable to receive them because of distance or local terrain.1 In United States v. Southwestern Cable Co., 392 U. S. 157 (1968), where we sustained the jurisdiction of [651]*651the Federal Communications Commission to regulate the new industry, at least to the extent “reasonably ancillary to the effective performance of the Commission’s various responsibilities for the regulation of television broadcasting,” id., at 178, we observed that the growth of CATV since the establishment of the first commercial system in 1950 has been nothing less than “ 'explosive.’ ” Id., at 163.2 The potential of the new industry to augment communication services now available is equally phenomenal.3 As we said in Southwestern, id., at 164, CATV “[promises] for the future to provide a national communications system, in which signals from selected broadcasting centers would be transmitted to metropolitan areas throughout the country.” Moreover, as the Commission has noted, “the expanding multichannel capacity of cable systems could be utilized to provide a variety of new communications services to homes and businesses within a community,” such as facsimile reproduction of documents, electronic mail delivery, and information retrieval. Notice of Proposed Rulemaking and Notice of Inquiry, 15 F. C. C. 2d 417, 419-420 (1968). Perhaps more important, CATV systems can themselves originate programs, or “cablecast” — which means, the Commission has found, that CATV can “[increase] the number of local outlets for community self-expression and [augment] the public’s choice of programs and types of service, without use of broadcast spectrum . . . .” Id., at 421.
[652]*652Recognizing this potential, the Commission, shortly after our decision in Southwestern, initiated a general inquiry “to explore the broad question of how best to obtain, consistent with the public interest standard of the Communications Act, the full benefits of developing communications technology for the public, with particular immediate reference to CATV technology . . . Id., at 417. In particular, the Commission tentatively concluded, as part of a more expansive program for the regulation of CATV,4 “that, for now and in general, CATV program origination is in the public interest,” id.,^~^ at 421, and sought comments on a proposal “to condition \ the carriage of television broadcast signals (local or dis- 1 tant) upon a requirement that the CATV system also ■ operate to a significant extent as a local outlet by origi- / [653]*653nating.” Id., at 422. As for its authority to impose such a requirement, the Commission stated that its “concern with CATV carriage of broadcast signals is not just a matter of avoidance of adverse effects, but extends also to requiring CATV affirmatively to further statutory policies.” Ibid.
On the basis of comments received, the Commission on October 24, 1969, adopted a rule providing that “no CATV system having 3,500 or more subscribers shall carry the signal of any television broadcast station unless the system also operates to a significant extent[5] as a local outlet by cablecasting [6] and has available facilities for local production and presentation of programs other [654]*654than automated services.” 47 CFR §74.1111 (a).7 In a report accompanying this regulation, the Commission stated that the tentative conclusions of its earlier notice of proposed rulemaking
“recognize the great potential of the cable technology to further the achievement of long-established regulatory goals in the field of television broadcasting by increasing the number of outlets for community self-expression and augmenting the public’s choice of programs and types of services .... They also reflect our view that a multi-purpose CATV operation combining carriage of broadcast signals with program origination and common carrier services/8-1 might best exploit cable channel capacity to the advantage of the public and promote the basic purpose for which this Commission was created: 'regulating interstate and foreign commerce in com[655]*655munication by wire and radio so as to make available, so far as possible, to all people of the United States a rapid, efficient, nationwide, and worldwide wire and radio communication service with adequate facilities at reasonable charges . . (sec. 1 of the Communications Act).[9] After full consideration of the comments filed by the parties, we adhere to the view that program origination on CATV is in the public interest.”10 First Report and Order, 20 F. C. C. 2d 201, 202 (1969).
[656]*656The Commission further stated, id., at 208-209:
“The use of broadcast signals has enabled CATV to finance the construction of high capacity cable facilities. In requiring in return for these uses of radio that CATV devote a portion of the facilities to providing needed origination service, we are furthering our statutory responsibility to 'encourage the larger and more effective use of radio in the public interest’ (sec. 303 (g))[11] The requirement will also facilitate the more effective performance of the Commission’s duty to provide a fair, efficient, and equitable distribution of television service to each of the several States and communities (sec. 307 (b)),[12] in areas where we have been unable to accomplish this through broadcast media.” 13
[657]*657Upon the challenge of respondent Midwest Video Corp., an operator of CATV systems subject to the new cablecasting requirement, the United States Court of Appeals for the Eighth Circuit set aside the regulation on the ground that the Commission “is without authority to impose” it. 441 F. 2d 1322, 1328 (1971).14 “The Commission’s power [over CATV] . . . ,” the court explained, “must be based on the Commission’s right to adopt rules that are reasonably ancillary to its responsi[658]*658bilities in the broadcasting field,” id., at 1326 — a standard that the court thought the Commission’s regulation “goes far beyond.” Id., at 1327.15 The court’s opinion may also be understood to hold the regulation invalid as not supported by substantial evidence that it would serve the public interest. “The Commission report itself shows,” the court said, “that upon the basis of the record made, it is highly speculative whether there is sufficient expertise or information available to support a finding that the origination rule will further the public interest.” Id., at 1328. “Entering into the program origination field involves very substantial expenditures,” id., at 1327, and “[a] high probability exists that cablecasting will not be self-supporting,” that there will be a “substantial increase” in CATV subscription fees, and that “in some instances” CATV operators will be driven out of business. Ibid.16 We granted certiorari. 404 U. S. 1014 (1972). We reverse.
[659]*659I
In 1966 the Commission promulgated regulations that, in general, required CATV systems (1) to carry, upon request and in a specified order of priority within the limits of their channel capacity, the signals of broadcast stations into whose service area they brought competing signals; (2) to avoid, upon request, the duplication on the same day of local station programing; and (3) to refrain from bringing new distant signals into the 100 largest television markets except upon a prior showing that that service would be consistent with the public interest. See Second Report and Order, 2 F. C. C. 2d 725 (1966). In assessing the Commission’s jurisdiction over CATV against the backdrop of these regulations,17 we focused in Southwestern chiefly on § 2 (a) of the Communications Act, 48 Stat. 1064, as amended, 47 U. S. C. 1152 (a), which provides in pertinent part: “The provisions of this [Act] shall apply to all interstate and foreign communication by wire or radio . . . , which originates and/or is received within the United States, and to all persons engaged within the United States in such communication . . . .” In view of the Act’s definitions of “communication by wire” and “communication by radio,”18 the interstate character of CATV services,19 [660]*660and the evidence of congressional intent that “[t]he Commission was expected to serve as the 'single Government agency’ with 'unified jurisdiction’ and 'regulatory power over all forms of electrical communication, whether by telephone, telegraph, cable, or radio,’ ” 392 U. S., at 167-168 (footnotes omitted), we held that § 2 (a) amply covers CATV systems and operations. We also held that § 2 (a) is itself a grant of regulatory power and not merely a prescription of the forms of communication to which the Act’s other provisions governing common carriers and broadcasters apply:
“We cannot [we said] construe the Act so restrictively. Nothing in the language of § [2 (a)], in the surrounding language, or in the Act’s history or purposes limits the Commission’s authority to those activities and forms of communication that are specifically described by the Act’s other provisions. . . . Certainly Congress could not in 1934 have foreseen the development of community antenna television systems, but it seems to us that it was precisely because Congress wished 'to maintain, through appropriate administrative control, a grip on the dynamic aspects of radio transmission,’ F. C. C. v. Pottsville Broadcasting Co., [309 U. S.], [661]*661at 138, that it conferred upon the Commission a ‘unified jurisdiction’ and ‘broad authority.’ Thus, ‘[underlying the whole [Communications Act] is recognition of the rapidly fluctuating factors characteristic of the evolution of broadcasting and of the corresponding requirement that the administrative process possess sufficient flexibility to adjust itself to these factors.’ [Ibid.] Congress in 1934 acted in a field that was demonstrably ‘both new and dynamic,’ and it therefore gave the Commission ‘a comprehensive mandate,’ with ‘not niggardly but expansive powers.’ National Broadcasting Co. v. United States, 319 U. S. 190, 219. We have found no reason to believe that § [2] does not, as its terms suggest, confer regulatory authority over ‘all interstate . . . communication by wire or radio.’ ” Id., at 172-173 (footnotes omitted).
This conclusion, however, did not end the analysis, for § 2 (a) does not in and of itself prescribe any objectives for which the Commission’s regulatory power over CATV might properly be exercised. We accordingly went on to evaluate the reasons for which the Commission had asserted jurisdiction and found that “the Commission has reasonably concluded that regulatory authority over CATV is imperative if it is to perform with appropriate effectiveness certain of its other responsibilities.” Id., at 173. In particular, we found that the Commission had reasonably determined that “ ‘the unregulated explosive growth of CATV,’ ” especially through “its importation of distant signals into the service areas of local stations” and the resulting division of audiences and revenues, threatened to “deprive the public of the various benefits of [the] system of local broadcasting stations” that the Commission was charged with developing and overseeing under § 307 (b) of the [662]*662Act.20 Id., at 175. We therefore concluded, without expressing any view “as to the Commission’s authority, if any, to regulate CATV under any other circumstances or for any other purposes,” that the Commission does have jurisdiction over CATV “reasonably ancillary to the effective performance of [its] various responsibilities for the regulation of television broadcasting . . . [and] may, for these purposes, issue 'such rules and regulations and prescribe such restrictions and conditions, not inconsistent with law,’ as ‘public convenience, interest, or necessity requires.’ ” Id., at 178 (quoting § 303 (r) of the Act, 50 Stat. 191, 47 U. S. C. § 303 (r)).
The parties now before us do not dispute that in light of Southwestern CATV transmissions are subject to the Commission’s jurisdiction as “interstate . . . communication by wire or radio” within the meaning of § 2 (a) even insofar as they are local cablecasts.21 The contro[663]*663versy, instead, centers on whether the Commission’s program-origination rule is “reasonably ancillary to the effective performance of [its] various responsibilities for the regulation of television broadcasting.” 22 We hold that it is.
[664]*664At the outset we must note that the Commission’s legitimate concern in the regulation of CATV is not limited to controlling the competitive impact CATV may-have on broadcast services. Southwestern refers to the Commission’s “various responsibilities for the regulation of television broadcasting.” These are considerably more numerous than simply assuring that broadcast stations operating in the public interest do not go out of business. Moreover, we must agree with the Commission that its “concern with CATV carriage of broadcast signals is not just a matter of avoidance of adverse effects, but extends also to requiring CATY affirmatively to further statutory policies.” Supra, at 653. Since the avoidance of adverse effects is itself the furtherance of statutory policies, no sensible distinction even in theory can be drawn along those lines. More important, CATV systems, no less than broadcast stations, see, e. g., Federal Radio Comm’n v. Nelson Bros. Co., 289 U. S. 266 (1933) (deletion of a station), may enhance as well as impair the appropriate [665]*665provision of broadcast services. Consequently, to define the Commission’s power in terms of the protection, as opposed to the advancement, of broadcasting objectives would artificially constrict the Commission in the achievement of its statutory purposes and be inconsistent with our recognition in Southwestern "that it was precisely because Congress wished ‘to maintain, through appropriate administrative control, a grip on the dynamic aspects of radio transmission,’ . . . that it conferred upon the Commission a ‘unified jurisdiction’ and ‘broad authority.’ ” Supra, at 660-661.23
The very regulations that formed the backdrop for our decision in Southwestern demonstrate this point. Those regulations were, of course, avowedly designed to guard broadcast services from being undermined by unregulated CATV growth. At the same time, the Commission recognized that “CATV systems . . . have arisen in response to public need and demand for improved television service and perform valuable public services in this respect.” Second Report and Order, 2 F. C. C. 2d 725, 745 (1966).24 Accordingly, the Commission’s express purpose was not
“to deprive the public of these important benefits or to restrict the enriched programing selection which
[666]*666CATV makes available. Rather, our goal here is to integrate the CATV service into the national television structure in such a way as to promote maximum television service to all people of the United States (secs. 1 and 303 (g) of the act [nn. 9 and 11, supra]), both those who are cable viewers and those dependent on off-the-air service. The new rules . . . are the minimum measures we believe to be essential to insure that CATV continues to perform its valuable supplementary role without unduly damaging or impeding the growth of television broadcast service.” Id., at 745-746.25
In implementation of this approach CATV systems were required to carry local broadcast station signals to encourage diversified programing suitable to the community's needs as well as to prevent a diversion of audiences and advertising revenues.26 The duplication of [667]*667local station programing was also forbidden for the latter purpose, but only on the same day as the local broadcast so as “to preserve, to the extent practicable, the valuable public contribution of CATV in providing wider access to nationwide programing and a wider selection of programs on any particular day.” Id., at 747. Finally, the distant-importation rule was adopted to enable the Commission to reach a public-interest determination weighing the advantages and disadvantages of the proposed service on the facts of each individual case. See id., at 776, 781-782. In short, the regulatory authority asserted by the Commission in 1966 and generally sustained by this Court in Southwestern was authority to regulate CATV with a view not merely to protect but to promote the objectives for which the Commission had been assigned jurisdiction over broadcasting.
In this light the critical question in this case is whether the Commission has reasonably determined that its origination rule will “further the achievement of long-estab[668]*668lished regulatory goals in the field of television broadcasting by increasing the number of outlets for community self-expression and augmenting the public's choice of programs and types of services . . . Supra, at 654. We find that it has.
The goals specified are plainly within the Commission's mandate for the regulation of television broadcasting.27 In National Broadcasting Co. v. United States, 319 U. S. 190 (1943), for example, we sustained Commission regulations governing relations between broadcast stations and network organizations for the purpose of preserving the stations' ability to serve the public interest through their programing. Noting that “[t]he facilities of radio are not large enough to accommodate all who wish to use them,'' id., at 216, we held that the Communications “Act does not restrict the Commission merely to supervision of [radio] traffic. It puts upon the Commission the burden of determining the composition of that traffic.” Id., at 215-216. We then upheld the Commission’s judgment that
“‘[w]ith the number of radio channels limited by natural factors, the public interest demands that those who are entrusted with the available channels shall make the fullest and most effective use of them.’ ” Id., at 218.
“ 'A station licensee must retain sufficient freedom of action to supply the program . . . needs of the local community. Local program service is a vital part of community life. A station should be ready, [669]*669able, and willing to serve the needs of the local community by broadcasting such outstanding local events as community concerts, civic meetings, local sports events, and other programs of local consumer and social interest.’ ” Id., at 203.
Equally plainly the broadcasting policies the Commission has specified are served by the program-origination rule under review. To be sure, the cablecasts required may be transmitted without use of the broadcast spectrum. But the regulation is not the less, for that reason, reasonably ancillary to the Commission’s jurisdiction over broadcast services. The effect of the regulation, after all, is to assure that in the retransmission of broadcast signals viewers are provided suitably diversified programing — the same objective underlying regulations sustained in National Broadcasting Co. v. United States, supra, as well as the local-carriage rule reviewed in Southwestern and subsequently upheld. See supra, at 666 and nn. 17 and 26, supra. In essence the regulation is no different from Commission rules governing the technological quality of CATV broadcast carriage. In the one case, of course, the concern is with the strength of the picture and voice received by the subscriber, while in the other it is with the content of the programing offered. But in both cases the rules serve the policies of §§ 1 and 303 (g) of the Communications Act on which the cablecasting regulation is specifically premised, see supra, at 654-656,28 and also, in the Commission’s words, [670]*670“facilitate the more effective performance of [its] duty to provide a fair, efficient, and equitable distribution of television service to each of the several States and communities” under § 307 (b). Supra, at 656.29 In sum, the regulation preserves and enhances the integrity of broadcast signals and therefore is “reasonably ancillary to the effective performance of the Commission’s various responsibilities for the regulation of television broadcasting.”
Respondent, nevertheless, maintains that just as the Commission is powerless to require the provision of television broadcast services where there are no applicants for station licenses no matter how important or desirable those services may be, so, too, it cannot require CATV operators unwillingly to engage in cablecasting. In our view, the analogy respondent thus draws between entry into broadcasting and entry into cablecasting is misconceived. The Commission is not attempting to compel wire service where there has been no commitment to undertake it. CATV operators to whom the cablecasting rule applies have voluntarily engaged themselves in providing that service, and the Commission seeks only to ensure that it satisfactorily meets community needs within the context of their undertaking.
For these reasons we conclude that the program-origination rule is within the Commission’s authority recognized in Southwestern.
[671]*671II
The question remains whether the regulation is supported by substantial evidence that it will promote the public interest. We read the opinion of the Court of Appeals as holding that substantial evidence to that effect is lacking because the regulation creates the risk that the added burden of cablecasting will result in increased subscription rates and even the termination of CATV services. That holding is patently incorrect in light of the record.
In first proposing the cablecasting requirement, the Commission noted that “[t]here may ... be practical limitations [for compliance] stemming from the size of some CATV systems” and accordingly sought comments “as to a reasonable cutoff point [for application of the regulation] in light of the cost of the equipment and personnel minimally necessary for local originations.” Notice of Proposed Rulemaking and Notice of Inquiry, 15 F. C. C. 2d 417, 422 (1968). The comments filed in response to this request included detailed data indicating, for example, that a basic monochrome system for cablecasting could be obtained and operated for less than an annual cost of $21,000 and a color system, for less than $56,000. See First Report and Order 210. This information, however, provided only a sampling of the experience of the CATV systems already engaged in program origination. Consequently, the Commission
“decided not to prescribe a permanent minimum cutoff point for required origination on the basis of the record now before us. The Commission intends to obtain more information from originating systems about their experience, equipment, and the nature of the origination effort. ... In the meantime, we [672]*672will prescribe a very liberal standard for required origination, with a view toward lowering this floor in . . . further proceedings, should the data obtained in such proceedings establish the appropriateness and desirability of such action.” Id., at 213.
On this basis the Commission chose to apply the regulation to systems with 3,500 or more subscribers, effective January 1, 1971.
“This standard [the Commission explained] appears more than reasonable in light of the [data filed], our decision to permit advertising at natural breaks . . . , and the 1-year grace period. Moreover, it appears that approximately 70 percent of the systems now originating have fewer than 3,500 subscribers; indeed, about half of the systems now originating have fewer than 2,000 subscribers. . . . [T]he 3,500 standard will encompass only a very small percentage of existing systems at present subscriber levels, less than 10 percent.” Ibid.
On petitions for reconsideration the Commission observed that it had “been given no data tending to demonstrate that systems with 3,500 subscribers cannot cablecast without impairing their financial stability, raising rates or reducing the quality of service.” Memorandum Opinion and Order 826. The Commission repeated that “[t]he rule adopted is minimal in the light of the potentials of cablecasting,”30 but, nonetheless, on its own motion postponed the effective date of the regulation to April 1, 1971, “to afford additional preparation time.” Id., at 827.
This was still not the Commission’s final effort to tailor the regulation to the financial capacity of CATV oper[673]*673ators. In denying respondent’s motion for a stay of the effective date of the rule, the Commission reiterated that “there has been no showing made to support the view that compliance . would be an unsustainable burden.” Memorandum Opinion and Order, 27 F. C. C. 2d 778, 779 (1971). On the other hand, the Commission recognized that new information suggested that CATV systems of 10,000 ultimate subscribers would operate at a loss for at least four years if required to cablecast. That information, however, was based on capital expenditure and annual operating cost figures “appreciably higher” than those first projected by the Commission. Ibid. The Commission concluded:
“While we do not consider that an adequate showing has been made to justify general change, we see no public benefit in risking injury to CATV systems in providing local origination. Accordingly, if CATV operators with fewer than 10,000 subscribers request ad hoc waiver of [the regulation], they will not be required to originate pending action on their waiver requests. . . . Systems of more than 10,000 subscribers may also request waivers, but they will not be excused from compliance unless the Commission grants a requested waiver .... [The] benefit [of cablecasting] to the public would be delayed if the . . . stay [requested by respondent] is granted, and the stay would, therefore, do injury to the public’s interest.” Ibid.
This history speaks for itself. The cablecasting requirement thus applied is plainly supported by substantial evidence that it will promote the public interest.31 Indeed, respondent does not appear to argue [674]*674to the contrary. See Tr. of Oral Arg. 43-44. It was, of course, beyond the competence of the Court of Appeals itself to assess the relative risks and benefits of cablecasting. As we said in National Broadcasting Co. v. United States, 319 U. S., at 224:
“Our duty is at an end when we find that the action of the Commission was based upon findings supported by evidence, and was made pursuant to authority granted by Congress. It is not for us to [675]*675say that the ‘public interest’ will [in fact] be furthered or retarded by the . . . [regulation]
See also, e. g., United States v. Storer Broadcasting Co., 351 U. S. 192, 203 (1956); General Telephone Co. of Southwest v. United States, 449 F. 2d 846, 858-859, 862-863 (CA5 1971).
Reversed.