31 U.S.C. § 1346

(a) Except as provided in this section— (1) public money and appropriations are not available to pay— (A) the pay or expenses of a commission, council, board, or similar group, or a member of that group; (B) expenses related to the work or the results of work or action of that group; or (C) for the detail or cost of personal services of an officer or employee from an executive agency in connection with that group; and (2) an accounting or disbursing official, absent a special appropriation to pay the account or charge, may not allow or pay an account or charge related to that group. (b) Appropriations of an executive agency are available for the expenses of an interagency group conducting activities of interest common to executive agencies when the group includes a representative of the agency. The representatives receive no additional pay because of membership in the group. An officer or employee of an executive agency not a representative of the group may not receive additional pay for providing services for the group. (c) Subject to section 1347 of this title , this section does not apply to— (1) commissions, councils, boards, or similar groups authorized by law; (2) courts-martial or courts of inquiry of the armed forces; or (3) the contingent fund related to foreign relations at the disposal of the President.