"WHEREAS the interests of the national security require that all persons privileged to be employed in the departments and agencies of the Government, shall be reliable, trustworthy, of good conduct and character, and of complete and unswerving loyalty to the United States; and WHEREAS the American tradition that all persons should receive fair, impartial, and equitable treatment at the hands of the Government requires that all persons seeking the privilege of employment or privileged to be employed in the departments and agencies of the Government be adjudged by mutually consistent and no less than minimum standards and procedures among the departments and agencies governing the employment and retention in employment of persons in the Federal service: NOW, THEREFORE, by virtue of the authority vested in me by the Constitution and statutes of the United States, including section 1753 of the Revised Statutes of the United States (5 U.S.C. 631); the Civil Service Act of 1883 (22 Stat. 403; 5 U.S.C. 632, et seq.); section 9A of the act of August 2, 1939, 53 Stat. 1148 (5 U.S.C. 118j); and the act of August 26, 1950, 64 Stat. 476 (5 U.S.C. 22-1, et seq.), and as President of the United States, and deeming such action necessary in the best interests of the national security, it is hereby ordered as follows: Section 1. In addition to the departments and agencies specified in the said act of August 26, 1950, and Executive Order No. 10237 of April 26, 1951, the provisions of that act shall apply to all other departments and agencies of the Government."
Executive Order 10450; EO 10450
Federal Register: http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR
Federal Register (April 27, 1953)