A presidential directive, or executive action, is a written or oral instruction or declaration issued by the president of the United States, which may draw upon the powers vested in the president by the U.S. Constitution, statutory law, or, in certain cases, congressional and judicial acquiescence. Such directives, which have been issued since the earliest days of the federal government, have become known by various names, and some have prescribed forms and purposes. Presidential directives remain in effect until they are revoked, which the president is free to do. The classification of presidential directives is not easily done, as the distinction between the types can be quite arbitrary, arising from convenience and bureaucratic evolution, and none are defined in the Constitution. Furthe