dissenting.
When the Framers of the Constitution granted Congress the authority “[t]o establish Post Offices and Post Roads,” Art. I, § 8, cl. 7, they placed the powers of the Federal Government behind a national communication service. Protecting the economic viability and efficiency of that service remains a legitimate and important congressional objective. This case involves a statute defended on that ground, but I believe it is unnecessary for achieving that purpose and inconsistent with the underlying commitment to communication.
The challenged statute, 18 U. S. C. § 1725, prohibits anyone from knowingly placing unstamped “mailable matter” in any box approved by the United States Postal Service for receiving or depositing material carried by the Postal Service. Violators may be punished with fines of up to $300 for each offense. In this case, appellee civic associations claimed, and *143the District Court agreed, that this criminal statute unreasonable restricts their First Amendment right of free expression.
The Court today upholds the statute on the theory that its focus — -the letterbox situated on residential property — is not a public forum to which the First Amendment guarantees access. I take exception to the result, the analysis, and the premise that private persons lose their prerogatives over the letterboxes they own and supply for mail service.
First, I disagree with the Court’s assumption that if no public forum is involved, the only First Amendment challenges to be considered are whether the regulation is content-based, see ante, at 132-133, and reasonable, ante, at 131, n. 7. Even if the Postal Service were not a public forum, which, as I later suggest, I do not accept, the statute advanced in its aid is a law challenged as an abridgment of free expression. Appellees seek to carry their own circulars and to deposit them in letterboxes owned by private persons who use them to receive mail, and challenge the criminal statute forbidding this use of private letterboxes. The question, then, is whether this statute burdens any First Amendment rights enjoyed by appellees. If so, it must be determined whether this burden is justified by a significant governmental interest substantially advanced by the statute. See Consolidated Edison Co. v. Public Service Comm’n, 447 U. S. 530, 540 (1980); Grayned v. City of Rockford, 408 U. S. 104, 115 (1972); Cameron v. Johnson, 390 U. S. 611, 616-617 (1968); Thornhill v. Alabama, 310 U. S. 88, 96, 104-105 (1940).
That appellee civic associations enjoy the First Amendment right of free expression cannot be doubted; both their purposes and their practices fall within the core of the First Amendment’s protections. We have long recognized the constitutional rights of groups which seek, as appellees do, to “communicate ideas, positions on local issues, and civic information to their constituents” 1 through written handouts *144and thereby to promote the free discussion of governmental affairs so central to our democracy. See, e. g., Martin v. City of Struthers, 319 U. S. 141, 146-147 (1943); Schneider v. State, 308 U. S. 147 (1939); Lovell v. Griffin, 303 U. S. 444 (1938). By traveling door to door to hand-deliver their messages to the homes of community members, appellees employ the method of written expression most accessible to those who are not powerful, established, or well financed. “Door to door distribution of circulars is essential to the poorly financed causes of little people.” Martin v. City of Struthers, supra, Sit 146. See Schneider v. State, supra, at 164. Moreover, “[f]reedom of speech, freedom of the press, freedom of religion are available to all, not merely to those who can pay their own way.” Murdock v. Pennsylvania, 319 U. S. 105, 111 (1943). And such freedoms depend on liberty to circulate ; “ 'indeed, without circulation, the publication would be of little value.' ” Talley v. California, 362 U. S. 60, 64 (1960), quoting Lovell v. Griffin, supra, at 452.
Countervailing public interests, such as protection against fraud and preservation of privacy, may warrant some limitation on door-to-door solicitation and canvassing. But we have consistently held that any such restrictions, to be valid, must be narrowly drawn “ 'in such a manner as not to intrude upon the rights of free speech.' ” Hynes v. Mayor and Council of Borough of Oradell, 425 U. S. 610, 616 (1976), quoting Thomas v. Collins, 323 U. S. 516, 540-541 (1945). Consequently, I cannot agree with the Court's conclusion, ante, at 132-133, that we need not ask whether the ban against placing such messages in letterboxes is a restriction on appellees’ free expression rights. Once appellees are at the doorstep, only § 1725 restricts them from placing their circulars in the box provided by the resident. The District Court determined after an evidentiary hearing that only by placing their circulars in the letterboxes may appellees be certain that their messages will be secure from wind, rain, or snow, and at the same time will alert the attention of the residents without *145notifying would-be burglars that no one has returned home to remove items from doorways or stoops. 490 F. Supp. 157, 160-163 (1980). The court concluded that the costs and delays of mail service put the mails out of appellees’ reach, and that other alternatives, such as placing their circulars in doorways, are “much less satisfactory.” Id., at 160.2 We have in the past similarly recognized the burden placed on First Amendment rights when the alternative channels of communication involve more cost, less autonomy, and reduced likelihood of reaching the intended audience. Linmark Associates, Inc. v. Willingboro, 431 U. S. 85, 93 (1977).
I see no ground to disturb these factual determinations of the trier of fact. And, given these facts, the Postal Service bears a heavy burden to show that its interests are legitimate and substantially served by the restriction of appellees’ freedom of expression. See, e. g., Hynes v. Mayor and Council of the Borough of Oradell, supra, at 617-618; Konigsberg v. State Bar of California, 366 U. S. 36, 49-51 (1961); Marsh v. Alabama, 326 U. S. 501, 509 (1946). Although the majority does not rule that the trial court’s findings were clearly erroneous, as would be required to set them aside, the Court finds persuasive the interests asserted by the Postal Service in defense of the statute. Those interests — “protecting] mail revenues while at the same time facilitating the secure and efficient delivery of the mails,” ante, at 129 — are indeed both legitimate and important. But mere assertion of an important, legitimate interest does not satisfy the requirement that the challenged restriction specifically and precisely serve that end. See Hynes v. Mayor and Council of the Borough of *146Oradell, supra. See also Cox v. Louisiana, 379 U. S. 536, 557-558 (1965) (restriction must be applied uniformly and nondiscriminatorily).
Here, the District Court concluded that the Postal Service “has not shown that failure to enforce the statute as to [ap-pellees] would result in a substantial loss of revenue, or a significant reduction in the government’s ability to protect the mails by investigating and prosecuting mail theft, mail fraud, or unauthorized private mail delivery service.” 490 P. Supp., at 163.3 In light of this failure of proof, I cannot join the Court’s conclusion that the Federal Government may thus curtail appellees’ ability to inform "community residents about local civic matters. That decision, I fear, threatens a departure from this Court’s belief that free expression, as “the matrix, the indispensable condition, of nearly every other form of freedom,” Palko v. Connecticut, 302 U. S. 319, 327 (1937), must not yield unnecessarily before such governmental interests as economy or efficiency. Certainly, free expression should not have to yield here, where the intruding statute has seldom been enforced.4 As the exceptions created *147by the Postal Service itself demonstrate,5 the statute’s asserted purposes easily could be advanced by less intrusive alternatives, such as a nondiscriminatory permit requirement for depositing unstamped circulars in letterboxes.6 Therefore, I would find 18 U. S. C. § 1725 constitutionally defective.
Even apart from the result in this case, I must differ with the Court’s use of the public forum concept to avoid application of the First Amendment. Rather than a threshold barrier that must be surmounted before reaching the terrain of the First Amendment, the concept of a public forum has more properly been used to open varied governmental locations to equal public access for free expression, subject to the constraints on time, place, or manner necessary to preserve the governmental function. E. g., Grayned v. City of Rockford, 408 U. S., at 115-117 (area around public school); Chicago Area Military Project v. Chicago, 508 F. 2d 921 (CA7) (city airport), cert, denied, 421 U. S. 992 (1975); Albany Welfare Rights Organization v. Wyman, 493 F. 2d 1319 (CA2) (welfare office waiting room), cert, denied sub nom. Lavine v. Albany Welfare Rights Organization, 419 U. S. 838 (1974); *148Wolin v. Port of New York Authority, 392 F. 2d 83 (CA2) (port authority), cert, denied, 393 U. S. 940 (1968); Reilly v. Noel, 384 F. Supp. 741 (RI 1974) (rotunda of courthouse). See generally Lehman v. City of Shaker Heights, 418 U. S. 298, 303 (1974); Stone, Fora Americana: Speech in Public Places, S. Ct. Rev. 233, 251-252 (1974). These decisions apply the public forum concept to secure the First Amendment’s commitment to expression unfettered by governmental designation of its proper scope, audience, or occasion.
I believe these precedents support my conclusion that ap-pellees should prevail in their First Amendment claim. The traditional function of the mails led this Court to embrace Justice Holmes’ statement that ‘“[t]he United States may give up the Post Office when it sees fit, but while it carries it on the use of the mails is as much a part of free speech as the right to use our tongues ....’” Lamont v. Postmaster General, 381 U. S. 301, 305 (1965), quoting United States ex rel. Milwaukee Social Democratic Pub. Co. v. Burleson, 255 U. S. 407, 437 (1921) (Holmes, J., dissenting). Given its pervasive and traditional use as purveyor of written communication, the Postal Service, I believe, may properly be viewed as a public forum. The Court relies on easily distinguishable cases in reaching the contrary conclusion. For the Postal Service’s very purpose is to facilitate communication, which surely differentiates it from the military bases, jails, and mass transportation discussed in cases relied on by the Court, ante, at 129-130.7 Cf. Tinker v. Des Moines Independent School *149Dist., 393 U. S. 503, 512 (1969). Drawing from the exceptional cases, where speech has been limited for special reasons, does not strike me as commendable analysis.
The inquiry in our public forum cases has instead asked whether "the manner of expression is basically incompatible *150with the normal activity of a particular place at a particular time.” Grayned v. City of Rockford, 408 U. S., at 116. Compare Grayned v. City of Rockford (restriction on speech permissible near school while in session) with Tinker v. Des Moines Independent School Dist., supra (symbolic speech protected even during school hours); Cameron v. Johnson, 390 U. S. 611 (1968) (restriction on picketing permitted where limited to entrance of courthouse), with Brown v. Louisiana, 383 U. S. 131 (1966) (silent protest in library protected); Adderley v. Florida, 385 U. S. 39 (1966) (protest near jailyard inconsistent with jail purposes), with Edwards v. South Carolina, 372 U. S. 229 (1963) (protest permitted on state capitol grounds). Assuming for the moment that the letterboxes, as “authorized depositories,” are under governmental control and thus part of the governmental enterprise, their purpose is hardly incompatible with appellees’ use. For the letterboxes are intended to receive written communication directed to the residents and to protect such materials from the weather or the intruding eyes of would-be burglars.
Reluctance to treat the letterboxes as public forums might stem not from the Postal Service’s approval of their form but instead from the fact that their ownership and use remain in the hands of private individuals.8 Even that hesitation, I should think, would be misguided, for those owners necessarily retain the right to receive information as a counterpart of the right of speakers to speak, Kleindienst v. Mandel, 408 U. S. 753, 762-765 (1972); Red Lion Broadcasting Co. v. FCC, 395 U. S. 367, 389-390 (1969); Lamont v. Postmaster General, supra, at 307; Martin v. City of Struthers, 319 U. S., at 143. Cf. Procunier v. Martinez, 416 U. S. 396, 408 (1974) (communication by letter depends on receipt by addressee). On that basis alone, I would doubt the validity of 18 U. S. C. § 1725, for it deprives residents of the informa*151tion which civic groups or individuals may wish to deliver to these private receptacles.9
I remain troubled by the Court’s effort to transform the letterboxes entirely into components of the governmental enterprise despite their private ownership. Under the Court’s reasoning, the Postal Service could decline to deliver mail unless the recipients agreed to open their doors to the letter carrier — and then the doorway, or even the room inside could fall within Postal Service control.10 Instead of starting with the scope of governmental control, I would adhere to our usual analysis which looks to whether the exercise of a First Amendment right is burdened by the challenged governmental action, and then upholds that action only where it is necessary to advance a substantial and legitimate governmental interest. In my view, the statute criminalizing the placement of hand-delivered civic association notices in letterboxes fails, this test. The brute force of the criminal sanction and other powers of the Government, I believe, may be *152deployed to restrict free expression only with greater justification. I dissent.
490 F. Supp. 157, 162 (1980).
Indeed, the record in this litigation indicates that appellees circulated less information when inhibited from using the letterboxes. Plaintiffs’ Answer to Written Interrogatories, Record, Doe. No. 23, ¶ 8, pp. 6-7. The practical effect of applying the statute in residential communities would preclude Girl Scouts, Boy Scouts, charities, neighbors, and others from leaving invitations or notes in the place residents most likely check for messages.
The Government’s interest in ensuring the security of the mails is advanced more directly by 18 U. S. C. §§ 1341, 1708. To the extent that the security and efficiency problems are attributed to overcrowding in letterboxes, the problem could be resolved simply by requiring larger boxes.
As for protection of mail revenues, it is significant that the District Court found the cost of using the mails prohibitive, given appellees' budgets, and the delays in mail delivery too great to make it useful for appellees’ needs. 490 F. Supp., at 160. Apparently, appellees’ compliance with 18 U. S. C. § 1725 would not increase mail revenues. Although protection of the Postal Service obviously must take the form of national regulation, having broad application, a statute’s nondiscriminatory terms may not save it where infringement of speech is demonstrated. Murdock v. Pennsylvania, 319 U. S. 105, 115 (1943).
Appellant conceded at oral argument that the Postal Service knew of no convictions and only one attempted prosecution under the statute. Tr. of Oral Arg. 15. That unsuccessful prosecution was dismissed because the District Court found impermissibly vague the prohibition on depositing *147unstamped “mailable matter such as statements of account, circulars, sales bills, or other like matter.” United States v. Rogers, Cr. No. 72-87 (MD La. Feb. 16, 1973) (emphasis added). Apparently, no prosecutions have since been attempted, although the statute may be used to support the efforts of local postal offices in collecting unpaid postage. Tr. of Oral Arg. 15.
The Postal Service has interpreted the statute to exempt mailslots, id., at 8, and to provide exception for certain kinds of deliveries. Domestic Mail Manual (DMM) 156.58 (newspapers, normally mailed but delivered on Sunday or holidays); 39 CFR § 310.6 (1979) (letters dispatched within 50 miles of destination and same-day delivery). And by applying only to “mailable matter,” the statute excludes pornography and other items not lawfully carried by the Postal Service. The Service thus has itself acknowledged that the statute sweeps more broadly than necessary.
Such a permit requirement could accomplish the central purpose of the statute — to restrain commercial enterprises from avoiding postal fees by employing their own delivery services. See ante, at 125.
Rather than supporting the conclusion that the Postal Service letterbox is not a public forum, the cases cited by the majority, ante, at 129-130, in fact point in the other direction. The Court resolved two First Amendment issues in Jones v. North Carolina Prisoners’ Union, 433 U. S. 119 (1977): the scope of associational rights retained by convicted prisoners, and their right, if any, to bulk mail rates. The Court analyzed both issues under the principle that while in prison, “an inmate does not retain those First Amendment rights that are ‘inconsistent with his status as a prisoner or with the legitimate penological objectives of the corree-*149tions system.’ ” Id., at 129, quoting Pell v. Procunier, 417 U. S. 817, 822 (1974). No such principle applies to appellees. Furthermore, the public forum analysis in Jones asked whether exercise of the First Amendment rights would be incompatible with the purposes of the governmental facility, a question answerable in the negative in this ease.
In Greer v. Spock, 424 U. S. 828, 838 (1976), the Court concluded that Fort Dix was not a public forum due to its military purpose and the power of “ 'the commanding officer summarily to exclude civilians from the area of his command’ ” (quoting Cafeteria Workers v. McElroy, 367 U. S. 886, 893 (1961)). At the same time, the Court emphasized that political campaign literature could still be distributed at the base unless it posed a clear danger to troop discipline and loyalty, 424 U. S., at 840. Thus, the base remained a “public forum” at least for written communication. A plurality of the Court in Lehman v. City of Shaker Heights, 418 U. S. 298, 303-304 (1974), found the city transit system not a public forum because its advertising space was incidental to its primary commercial transportation purpose. The plurality nevertheless recognized that the state action present necessitated a balancing analysis of the First Amendment interests of those seeking advertising space and the interests of the government and the users of the transit system. Further, both the plurality and Justice Douglas, in his separate opinion concurring in the result, relied on an analogy to the mass media which has no obligation under the First Amendment to broadcast or print any particular story or advertisement. Id., at 303 (opinion of Blackmun, J.); id., at 306 (opinion of Douglas, J.). In contrast, the Postal Service is obliged to accept all mailable matter. Finally, in Adderley v. Florida, 385 U. S. 39 (1966), the security needs of the jail were critical to the Court’s conclusion that trespassers on the jail grounds could properly be prosecuted. Adderley itself noted that spaces more traditionally used by the public would more likely be public forums, id., at 41-42, and this treatment is appropriate here, given the traditional public use of the Postal Service. The determinative question in each of these cases was not whether the government owned or controlled 'the property, but whether the nature of the governmental interests warranted the restrictions on expression. That is the question properly asked in this case.
But see Marsh v. Alabama, 326 U. S. 501 (1946).
The Court announced the First Amendment rights of recipients in Lamont v. Postmaster General, 381 U. S. 301 (1965). There, the Court struck down a postal regulation denying delivery of Communist propaganda sent from outside the country, even though the regulation permitted such delivery to recipients who notified the Postal Service in writing that they wished to receive the material. Untenable, in the Court’s view, was the fact that under the regulatory scheme, “[t]he addressee carries an.affirmative obligation which we do not think the Government may impose on him.” Id., at 307. The concern for the addressee’s First Amendment rights should govern here.
Appellant suggests no First Amendment problem is presented because residents would not erect letterboxes but for the Postal Service, and the First Amendment did not compel the creation of the Service. Brief for Appellant 18-19. This argument obviously proves too much, because the First Amendment did not ordain the establishment of schools or libraries, and yet we have held that once established, these public facilities must be managed consistently with the First Amendment. Tinker v. Des Moines Independent School Dist., 393 U. S. 503 (1969); Brown v. Louisiana, 383 U. S. 131 (1966).