22 U.S.C. § 2567

The President may appoint, by and with the advice and consent of the Senate, Special Representatives of the President for arms control, nonproliferation, and disarmament matters. Each Presidential Special Representative shall hold the rank of ambassador. Presidential Special Representatives appointed under this section shall perform their duties and exercise their powers under the direction of the President and the Secretary of State. The Department of State shall be the Government agency responsible for providing administrative support, including funding, staff, and office space, to all Presidential Special Representatives.