The American national government is engaged in a vast program of censorship which includes a wider range of materials than that usually controlled by local government authority. The attention of the courts and the press has been concentrated primarily upon state and local censorship, but federal activity is usually more significant. The federal government has used the postal and customs powers, derived from Article I, Sec. 8 of the Constitution, to regulate both the internal movement of undesirable material and its entry from abroad. The postal power has been treated elsewhere, but the customs power is at least as important because it can reach any material transported by any mode of communication as long as the point of origin is outside the United States. Not only is the customs power broader in scope, but its administration has been met with much less criticism and resistance than that of the Post Office.
Jay A. Sigler, 15 Clev.-Marshall L. Rev. 58 (1966)