U.S. Const. art. 1, § 6, cl. 2 No Senator or Representative shall, during the time for which he was elected, be appointed to any civil office under the authority of the United States, which shall have been created, or the emoluments whereof shall have been increased during such time: and no person holding any office under the United States, shall be a member of either House during his continuance in office.
U.S. Const. art. 1, § 9, cl. 8 No title of nobility shall be granted by the United States: and no person holding any office of profit or trust under them, shall, without the consent of the Congress, accept of any present, emolument, office, or title, of any kind whatever, from any king, prince, or foreign state. See also the Foreign Gifts and Decorations Act, 5 U.S.C. § 7342.
Øbama supposedly knows better, so should Clinton. The Constitution only matters when it can be used to stop Conservatives, not when it limits government or the high priests and priestesses of the Left in practicing their government religion.