31 U.S.C. § 3321 — Disbursing authority in the executive branch

(a) Except as provided in this section or another law, only officers and employees of the Department of the Treasury designated by the Secretary of the Treasury as disbursing officials may disburse public money available for expenditure by an executive agency. (b) For economy and efficiency, the Secretary may delegate the authority to disburse public money to officers and employees of other executive agencies. (c) The head of each of the following executive agencies must designate personnel of the agency as disbursing officials to disburse public money available for expenditure by the agency: (1) United States Marshal’s Office. (2) The Department of Defense. (3) The Department of Homeland Security. 1 (for public money available for expenditure by the Coast Guard when it is not operating as a service in the Navy). (d) On request of the Secretary and with the approval of the head of an executive agency referred to in subsection (c) of this section, facilities of the agency can be used to assist in disbursing public money available for expenditure by another executive agency.