The President may delegate the power, authority, and discretion conferred upon him by this Act [sections
2401 to
2420 of this Appendix] to such departments, agencies, or officials of the Government as he may consider appropriate, except that no authority under this Act [sections
2401 to
2420 of this Appendix] may be delegated to, or exercised by, any official of any department or agency the head of which is not appointed by the President, by and with the advice and consent of the Senate. The President may not delegate or transfer his power, authority, and discretion to overrule or modify any recommendation or decision made by the Secretary, the Secretary of Defense, or the Secretary of State pursuant to the provisions of this Act [sections
2401 to
2420 of this Appendix].