Mr. Chief Justice Burger
delivered the opinion of the Court.
We noted probable jurisdiction to review a summary-decision of the United States District Court for the Central District of California holding that § 305(a) of the Tariff Act of 1930, 46 Stat. 688, as amended, 19 U. S. C. § 1305 (a) was “unconstitutional on its face” and dismissing a forfeiture action brought under that statute. The statute provides in pertinent part:
“All persons are prohibited from importing into the United States from any foreign country . . . any obscene book, pamphlet, paper, writing, advertisement, circular, print, picture, drawing, or other representation, figure, or image on or of paper or other material, or any cast, instrument, or other article which is obscene or immoral .... No such articles whether imported separately or contained in packages with other goods entitled to entry, shall be admitted to entry; and all such articles and, unless it appears to the satisfaction of the appropriate customs officer that the obscene or other prohibited articles contained in the package were inclosed therein without the knowledge or consent of the importer, owner, agent, or consignee, the entire contents of the package in which such articles are contained, shall be subject to seizure and forfeiture as hereinafter provided .... Provided further, That the Secretary of the Treasury may, in his discretion, admit the so-called classics or books of recognized and established literary or scientific merit, but may, in his discretion, admit such classics or books only when imported for noncommercial purposes.”
On April 2, 1970, the claimant Paladini sought to carry movie films, color slides, photographs, and other printed and graphic material into the United States from Mexico. The materials were seized as being obscene by customs officers at a port of entry, Los Angeles Airport, and made the subject of a forfeiture action under 19 U. S. C. § 1305 (a). The District Court dismissed the Government’s complaint, relying on the decision of a three-judge district court in United States v. Thirty-seven Photographs, 309 F. Supp. 36 (CD Cal. 1970), which we later reversed, 402 U. S. 363 (1971). That case concerned photographs concededly imported for commercial purposes. The narrow issue directly presented in this case, and not in Thirty-seven Photographs, is whether the United States may constitutionally prohibit importation of obscene material which the importer claims is for private, personal use and possession only.
Import restrictions and searches of persons or packages at the national borders rest on different considerations and different rules of constitutional law from domestic regulations. The Constitution gives Congress broad, comprehensive powers “[t]o regulate Commerce with foreign Nations.” Art. I, § 8, cl. 3. Historically such broad powers have been necessary to prevent smuggling and to prevent prohibited articles from entry. See United States v. Thirty-seven Photographs, 402 U. S., at 376-377 (opinion of White, J.); Carroll v. United States, 267 U. S. 132, 154 (1925); Brolan v. United States, 236 U. S. 216, 218 (1915); Boyd v. United States, 116 U. S. 616, 623-624 (1886); Alexander v. United States, 362 F. 2d 379, 382 (CA9), cert. denied, 385 U. S. 977 (1966). The plenary power of Congress to regulate imports is illustrated in a holding of this Court which sustained the validity of an Act of Congress prohibiting the importation of “any film or other pictorial representation of any prize fight . . . designed to be used or [that] may be used for purposes of public exhibition” in view of “the complete power of Congress over foreign commerce and its authority to prohibit the introduction of foreign articles .... Buttfield v. Stranahan, 192 U. S. 470; The Abby Dodge, 223 U. S. 166, 176; Brolan v. United States, 236 U. S. 216.” Weber v. Freed, 239 U. S. 325, 329 (1915).
Claimant relies on the First Amendment and our decision in Stanley v. Georgia, 394 U. S. 557 (1969). But it is now well established that obscene material is not protected by the First Amendment. Roth v. United States, 354 U. S. 476, 485 (1957), reaffirmed today in Miller v. California, ante, at 23. As we have noted in United States v. Orito, post, at 141-143, also decided today, Stanley depended, not on any First Amendment right to purchase or possess obscene materials, but on the right to privacy in the home. Three concurring Justices indicated that the case could have been disposed of on Fourth Amendment grounds without reference to the nature of the materials. Stanley v. Georgia, supra, at 569 (Stewart, J., joined by Brennan and White, JJ., concurring).
In particular, claimant contends that, under Stanley, the right to possess obscene material in the privacy of the home creates a right to acquire it or import it from another country. This overlooks the explicitly narrow and precisely delineated privacy right on which Stanley rests. That holding reflects no more than what Mr. Justice Harlan characterized as the law’s “solicitude to protect the privacies of the life within [the home].” Poe v. Ullman, 367 U. S. 497, 551 (1961) (dissenting opinion). The seductive plausibility of single steps in a chain of evolutionary development of a legal rule is often not perceived until a third, fourth, or fifth “logical” extension occurs. Each step, when taken, appeared a reasonable step in relation to that which preceded it, although the aggregate or end result is one that would never have been seriously considered in the first instance. This kind of gestative propensity calls for the “line drawing” familiar in the judicial, as in the legislative process: “thus far but not beyond.” Perspectives may change, but our conclusion is that Stanley represents such a line of demarcation; and it is not unreasonable to assume that had it not been so delineated, Stanley would not be the law today. See United States v. Reidel, 402 U. S. 351, 354-356 (1971); id., at 357-360 (Harlan, J., concurring). See also Miller v. United States, 431 F. 2d 655, 657 (CA9 1970); United States v. Fragus, 428 F. 2d 1211, 1213 (CA5 1970); United States v. Melvin, 419 F. 2d 136, 139 (CA4 1969); Gable v. Jenkins, 309 F. Supp. 998, 1000-1001 (ND Ga. 1969), aff’d, 397 U. S. 592 (1970). Cf. Karalexis v. Byrne, 306 F. Supp. 1363, 1366 (Mass. 1969), vacated on other grounds, 401 U. S. 216 (1971).
We are not disposed to extend the precise, carefully limited holding of Stanley to permit importation of admittedly obscene material simply because it is imported for private use only. To allow such a claim would be not unlike compelling the Government to permit importation of prohibited or controlled drugs for private consumption as long as such drugs are not for public distribution or sale. We have already indicated that the protected right to possess obscene material in the privacy of one’s home does not give rise to a correlative right to have someone sell or give it to others. United States v. Thirty-seven Photographs, supra, at 376 (opinion of White, J.), and United States v. Reidel, supra, at 355. Nor is there any correlative right to transport obscene material in interstate commerce. United States v. Orito, post, at 142-144. It follows that Stanley does not permit one to go abroad and bring such material into the country for private purposes. “Stanley’s emphasis was on the freedom of thought and mind in the privacy of the home. But a port of entry is not a traveler’s home.” United States v. Thirty-seven Photographs, supra, at 376 (opinion of White, J.).
This is not to say that Congress could not allow an exemption for private use, with or without appropriate guarantees such as bonding, or permit the transportation of obscene material under conditions insuring privacy. But Congress has not seen fit to do so, and the holding in Roth v. United States, supra, read with the narrow holding of Stanley v. Georgia, supra, does not afford a basis for claimant’s arguments. The Constitution does not compel, and Congress has not authorized, an exception for private use of obscene material. See Paris Adult Theatre I v. Slaton, ante, at 64-69; United States v. Reidel, supra, at 357; Memoirs v. Massachusetts, 383 U. S. 413, 462 (1966) (White, J., dissenting).
The attack on the overbreadth of the statute is thus foreclosed, but, independently, we should note that it is extremely difficult to control the uses to which obscene material is put once it enters this country. Even single copies, represented to be for personal use, can be quickly and cheaply duplicated by modern technology thus facilitating wide-scale distribution. While it is true that a large volume of obscene material on microfilm could rather easily be smuggled into the United States by mail, or otherwise, and could be enlarged or reproduced for commercial purposes, Congress is not precluded from barring some avenues of illegal importation because avenues exist that are more difficult to regulate. See American Power & Light Co. v. SEC, 329 U. S. 90, 99-100 (1946).
As this case came to us on the District Court’s summary dismissal of the forfeiture action, no determination of the obscenity of the materials involved has been made. We have today arrived at standards for testing the constitutionality of state legislation regulating obscenity. See Miller v. California, ante, at 23-25. These standards are applicable to federal legislation. The judgment of the District Court is vacated and the case is remanded for further proceedings consistent with this opinion, Miller v. California, supra, and United States v. Orito, supra, both decided today.
Vacated and remanded.
The United States brought this direct appeal under 28 U. S. C. § 1252. See Clark v. Gabriel, 393 U. S. 256, 258 (1968).
On the day the complaint was dismissed, claimant filed an affidavit with the District Court stating that none of the seized materials “were imported by me for any commercial purpose but were intended to be used and possessed by me personally.” In conjunction with the Government’s motion to stay the order of dismissal, denied below but granted by Mr. Justice BreNNAN, the Government conceded it had no evidence to contradict claimant’s affidavit and did not “contest the fact that this was a private importation.”
Act of July 31, 1912, c. 263, § 1, 37 Stat. 241.
Nor can claimant rely on any other sphere of constitutionally protected privacy, such as that which encompasses the intimate medical problems of family, marriage, and motherhood. See Paris Adult Theatre I v. Slaton, ante, at 65-67, and United States v. Orito, post, at 142-143.
Mr. Justice Holmes had this kind of situation in mind when he said:
“All rights tend to declare themselves absolute to their logical extreme. Yet all in fact are limited by the neighborhood of principles of policy which are other than those on which the particular right is founded, and which become strong enough to hold their own when a certain point is reached.” Hudson County Water Co. v. McCarter, 209 U. S. 349, 355 (1908).
In Caminetti v. United States, 242 U. S. 470 (1917), and Hoke v. United States, 227 U. S. 308 (1913), this Court upheld the “so-called White Slave Traffic Act, which was construed to punish any person engaged in enticing a woman from one State to another for immoral ends, whether for commercial purposes or otherwise, . . . because it was intended to prevent the use of interstate commerce to facilitate prostitution or concubinage, and other forms of immorality.” Brooks v. United States, 267 U. S. 432, 437 (1926) (emphasis added).
We further note that, while we must leave to state courts the construction of state legislation, we do have a duty to authoritatively construe federal statutes where " 'a serious doubt of constitutionality is raised’ ” and “ ‘a construction of the statute is fairly possible by which the question may be avoided.’ ” United States v. Thirty-seven Photographs, 402 U. S. 363, 369 (1971) (opinion of White, J.), quoting from Crowell v. Benson, 285 U. S. 22, 62 (1932). If and when such a “serious doubt” is raised as to the vagueness of the words “obscene,” “lewd,” “lascivious,” “filthy,” “indecent,” or “immoral” as used to describe regulated material in 19 U. S. C. § 1305 (a) and 18 U. S. C. § 1462, see United States v. Orito, post, at 140 n. 1, we are prepared to construe such terms as limiting regulated material to patently offensive representations or descriptions of that specific “hard core” sexual conduct given as examples in Miller v. California, ante, at 25. See United States v. Thirty-seven Photographs, supra, at 369-374 (opinion of White, J.). Of course, Congress could always define other specific “hard core” conduct.