970 HARVARD LAW REVIEW The federal government has restricted speech in two other ways besides punishment. It has excluded many publications from the mails. This is clearly previous restraint and might seem forbidden by the Blackstonian definition, which, however, is held not to apply to the postal power.^^^ This power, like the war power, ought to be subject to the requirements of free speech and due process of law, and there are dicta of the Supreme Court that it is not unlimited.^^^ Although the post-office may not be strictly a common carrier,^^^ it is in the nature of a public service company. Its functions have been performed by private persons in the past, and probably would be shared by them now if it were not unlawful because of the greater speed possible.^^ According to the political theories of Leon Duguit,^^^ the government in furnishing public service must be judged by ordinary standards of pubHc callings. If the United States owned the railroads, it ought not to make unreasonable discrimination among passengers any more than a private railroad corporation, and a similar limitation should apply to the postal power. The congressional restrictions which have been upheld by the courts may be considered as reasonable regulations in view of the nature of the service. Even opposition to the government may be entitled to some consideration by the post-office as by the write, or publish any language intended to incite, provoke, or encourage resistance to the United States, or to promote the cause of its enemies, or shall willfully display the flag of any foreign enemy, or shall willfully by utterance, writing, printing, publica- tion, or language spoken, urge, incite, or advocate any curtailment of production in this country of any thing or things, product or products, necessary or essential to the pros- ecution of the war in which the United States may be engaged, with intent by such curtailment to cripple or hinder the United States in the prosecution of the war, and whoever shall wiUfully advocate, teach, defend, or suggest the doing of any of the acts or things in this section emmierated, and whoever shall by word or act support or favor the cause of any country, with which the United States is at war or by word or act oppose the cause of the United States therein, shall be pvmished by a fine of not more than $10,000 or imprisonment for not more than twenty years, or both." The itaUcized words punish language for remote tendencies: Cf. the Sedition Act of 1798. 1^ Masses Pub. Co. v. Patten, 246 Fed. 24, 27 (1917), Rogers, J. The operation of our postal censorship is shown by WiUiam Hard's articles cited in note i, supra. 133 £x Parte Jackson, 96 U. S. 727 (1877); PubUc Clearing House v. Coyne, 194 U. S. 497, 507 (1904). 1" Masses Pub. Co. v. Patten, 245 Fed. 102, 106 (1917), Hough, J. 13* Something like this happened when the Western Union Telegraph Co. recently tried to carry "night-letters" by messengers on trains. , '" See H. J. Laski in 31 Harv. L. Rev. 186; and his Authority in the Modern State, p. 378.
