Section 6 of the Internal Security Act of 1950 makes it illegal for members of an organization which has registered under the Act as a communist organization or has been ordered to do so by the Subversive Activities Control Board, to apply for a passport, or to use or attempt to use a passport. It is also an offense for a federal officer knowingly to issue a passport to such a person. The Immigration and Nationality Act also empowers the President, in time of war or national emergency, to impose restrictions and prohibitions upon the departure of persons from the United States.[215] _Registration_: The requirement that specified categories of individuals register, in consequence of their backgrounds, associations, or activities, or as a result of possession of certain articles, becomes increasingly familiar in the United States. Legislative motivation in requiring such registration may be varied and complex. The registration provision invariably provides the basis for defining new crimes and therefore opportunity to prosecute persons whose backgrounds, activities and beliefs are anathema to powerful groups in the nation. Combined with periodic reporting, registration may act as a deterrent to the commission of certain acts considered socially or politically undesirable. It may simply facilitate the informative function of government, enabling authorities to become aware of and continuously check upon the activities of selected groups of persons affecting the public interest. Or, registration may serve as a mild, yet nonetheless effective, restraint upon the freedom of individuals. Certainly, for example, it is an essential prerequisite to paroling enemy aliens in time of war, although its usefulness is not limited to wartime only.