Pub. L. 106-58, tit. VI, sec. 619

Sec. 619. No part of any appropriation contained in this Act may be used to pay for the expenses of travel of employees, including employees of the Executive Office of the President, not directly responsible for the discharge of official governmental tasks and duties: Provided, That this restriction shall not apply to the family of the President, Members of Congress or their spouses, Heads of State of a foreign country or their designees, persons providing assistance to the President for official purposes, or other individuals so designated by the President.