Lyndon Johnson actually said...
I, Lyndon B. Johnson, President of the United States of America, acting under the authority vested in me by the Constitution and the statutes of the United States, including Section 2 of the Educational, Scientific, and Cultural Materials Importation Act of 1966, do proclaim that that Act shall become effective with respect to articles entered, or withdrawn from warehouse, for consumption on or after February 1, 1967.
11/02/1966