Mr. Justice Field,
after stating the case, delivered the opinion of the court.
The power vested in Congress "to establish post-oliices and post-roads " has been practically construed, since the foundation of the government, to authorize not merely the designation of the routes over which the mail shall be carried, and the offices where letters and other documents shall be received to be distributed or forwarded, but the. carriage of. the mail, and all measures necessary to .secure-its safe and speedy transit, and the prompt delivery of its contents. The validity of legislation prescribing what should be carried, and its weight and form, and the charges to which it should be subjected,'has never been questioned. What .should be mailable has varied at different times, changing with the facility of transportation .over the post-roads. At one time, only letters, newspapers, magazines, pamphlets, and other printed matter, not exceeding eight ounces in weight, were carried; afterwards books were added to the list.; and now small packages of merchandise, not exceeding a prescribed weight, as well as books Rnd printed matter of all kinds, are transported in the mail. The power possessed by Congress embraces the regulation of the entire postal system of the country. The right to designate what shall be carried necessarily involves the right to determine what shall be excluded. The difficulty attending the subject arises, not from the want of power in Congress to ,prescribe regulations as to what shall constitute.mail matter, but from the necessity of enforcing them consistently with rights reserved to the people, of far, greater importance than the transportation of the mail. In their en forcement, a. distinction is to be made between different kinds of mail matter, — between wbat is intended to be kept free from inspection, such as letters, and sealed packages subject to letter postage; and what is open to inspection, such as newspapers, magazines, pamphlets, and other printed matter, purposely left in'a condition to be examined. Lettersand.sealed packages of this kind in the mail are as fully guarded from examination and inspection, except as to their outward form and weight, as. if they were retained by the parties forwarding them in their own domiciles. The constitutional guaranty of the right of the people to be secure in their papers against unreasonable searches' and seizures extends to their papers, thus closed against inspection, wherever they may be. Whilst in the mail, they can only "be opened and examined under like warrant, issued upon similar oath or affirmation, particularly describing the thing to be seized, as is required when papers are subjected to search in one's, own household. No law of- Congress can place in the hands of officials connected with the postal service any authority to invade the secrecy of letters and such sealed' packages in the mail; and all regulations adopted as to mail matter of this kind must .be in subordination to the great principle embodied in the fourth amendment of the Constitution.
Nor can any regulations be enforced against the transportation of printed matter in the mail, which is open to examination, so as to interfere in any manner with the freedom of the press. Liberty of circulating is as essential to that freedom as liberty of publishing; indeed, without the circulation, the publication would be of little value. If, therefore, printed matter be excluded from the mails, its .transportation in any other way cannot be forbidden by 'Congress.
In 1836', the question as to the power of Congress.to exclude publications from the mail was discussed in the Senate; and the prevailing opinion of its members, as expressed in debate, was against the existence of the power. President Jackson, in his annual message of the previous year, had referred to the attempted circulation through the mail of inflammatory appeals, addressed to the passions of the slaves, in prints, and in various publications, tending to stimulate them to insurrection; and suggested to Congress the propriety of passing a law prohibiting, under severe penalties, such circulation of " incendiary publica tions " in the Southern States. In the Senate, that portion of the message was referred to a select committee, of which Mr. Calhoun was chairman; and he made -an elaborate report on the subject, in which he contended that-it belonged to the. States, and not to Congress, to determiné what is and what is not calculated to disturb their, security., and'that to'hold otherwise would be fatal to the States; for if Congress might determine what papers were incendiary, and as such prohibit their circulation through' the mail, it might also determine what were not incendiary, and enforce their circulation. Whilst, therefore, condemning in the strongest terms the circulation of the publications, he .insisted that Congress had not the power to pass a law prohibiting their transmission through the mail, on the ground that it would abridge the liberty of the'press. " To understand," he S,aid, " more- fully • the extent of the control which the right of prohibiting circulation through the mail would give to'the government over the press, iff must be borne in mind that the power of Congress over the post-office and the mail is an exclusive power. It must also be remembered that Congress, in the exercise of this power, may declare any road or navigable water to be a post-road; and that, by the act of 1825, it is providéd ' that no stage, or other vehicle which regularly performs trips on a poSt-road, or on a road parallel to it, shall carry letters.' The same provision extends to packets, boats, or other vessels on navigable waters. Like provision may be exténded to newspapers and pamphlets, which, if it ,be admitted that Congress has the right to discriminate in reference to their character, what papers shall or what shall not be transmitted by the mail, would subject the freedom of the press, on all subjects, political, moral, and religious, completely to its will and', pleasure. It would in fact, in some respects, more effectually control the freedom of the press than any sedition law, however severe its penalties." Mr. Calhoun, at the same time, contended that when a State had pronounced certaijn publications 'to be dangerous to its peace, and prohibited théir circulation, it was the duty of Congress to respect its laws and co-operate- in their enforcement; and whilst, therefore, Congress could not prohibit the transmission of the ipcendiarv documejats through the mails, it could prevent their delivery by the postmasters in the States where their circulation was forbidden. In the discussion upon the bill reported by :,hitfi, similar views against the power of Congress Were expressed by other senators, who did not concur in the opinion that the delivery of - papers could be prevented when their transmission was permitted.
Great reliance is placed by the petitioner upon these views, coming, as they did in smany' instances^ from men alike distinguished a¡s jurists and statesmen. But it is evident that they were founded upon the assumption that it was competent for Congress to prohibit the transportation of newspapers and pamphlets over postal-routes in any other.way than by mail; and of course it would follow,] that if, with such a prohibition, the transportation in the mail could also be forbidden, the circulation of the documents would be destroyed, and a fatal blow given to the freedom' of the press. But we do not think that Congress possesses the power to prevent the transportation in other ways, as merchandise, of matter which it excludes from the mails. - To give efficiency to its regulations and prevent rival postal systems, it .may perhaps prohibit the carriage by others for hire, over postal routes, of articles which legitimately constitute mail matter, in the sense in which those terms were used when the Constitution was adopted, consisting of letters, and of newspapers and pamphlets, when not sent as merchandise ; but further than this its power of prohibition cannot extend.
Whilst regulations excluding matter from the mail cannot be enforced in a way which would require or permit an examinar tion into letters, or sealed packages-subject to letter postage, without warrant, issued upon oath or affirmation, in the search for prohibited matter, they may be enforced upon-competent evidence of their violation obtained in other ways; as from the parties receiving the letters or packages, or from agents-depositing them in the post-office, or others cognizant of the facts.' And as to objectionable printed matter, which is open to examination, the regulations may be enforced .in a similar way, by the imposition of penalties for their violation through the courts, and, in some cases, by the direct action of the officers' of the postal servicé. In many instances, those officers can act upon their- own inspection, and, from the nature of the case, must act without other proof; as. where the postage is not prepaid, or where there' is an excess of weight over the amount prescribed, or where the object is exposed, and shows unmistakably -that it is prohibited, as in the case of an obscene picture or print. In such cases, no difficulty arisés, and no principle is violated, in excluding the prohibited, articles or refusing to forward them. The. evidence'respecting'them is seen by- every one, and is in its nature conclusive.
" In excluding various' articles from, the mail, the object of Congress has.- not been to interfere with the freedom of the press, or with any other rights of the people; but -to refuse its facilities for the distribution of matter deemed injurious to the public morals. Thus, by the act of March 3, 1873, Congress declared. " that no obscene, lewd, or lascivious book, pamphlet, picture, paper, print, or other publication of an indecent character, or any article or thing designed or intended for the prevention of conception or procuring of abortion, nor any, article or thing intended or adapted for any indecent or immoral use or- nature, nor any written or. printed card, circular, book, •pamphlet, advertisement, or notice of any kind, giving information, directly or indirectly, .where, or how; or of whom, or by what means, either- of the things before' mentioned may be-obtained or made, nor any. letter upon the envelope of- which, or. postal-card upon which indecent or scurrilous epithets may' be written or printed, shall be carried in the -mail; and any person who shall knowingly deposit, or cause to be deposited, for mailing or delivery, any of the hereinbefore mentioned arth cles or things, . . . shall' be deemed guilty of á misdemeanor, and, on conviction thereof, shall,' for every offence, be fined, not less than $100, nor more .than $5,000, or imprisonment at hard labor not less than one year nor more ' than tefa years, or both, in the discretion of the judge."
All that Congress meant by this act-was, that the mail should not be used to transport such corrupting publications and articles, and that any one who\attempted to use it for that purpose should be-punished. The same inhibition has been extended to circulars concerning lotteries, — institutions which are supposed to have a demoralizing, influence- upon the people. There is no question before us as to the evidence upon which thé conviction of the petitioner was had; nor does it appear whether the envelope in which the prohibited circular was deposited in the mail was sealed or left open for examination. The only question for our determination relates to the constitutionality of the act; and of that wé have no doubt.
The commitment of the petitioner to the county jail, until his fine was paid, was within the discretion of the court under the statute.
As there is an exemplified copy of the record of the petitioner's indictment and conviction accompanying the petition, .the merits of his case havé been considered at his request upon this application; and, as we are of opinion that his imprisonment is legal, no object would be subserved by issuing the writs; they are therefore
Denied.