10 USC § 377. Reimbursement
(a) Subject to subsection (c), to the extent otherwise required by section 1535 of title 31 (popularly known as the “Economy Act”) or other applicable law, the Secretary of Defense shall require a civilian law enforcement agency to which support is provided under this chapter to reimburse the Department of Defense for that support.
(b)(1) Subject to subsection (c), the Secretary of Defense shall require a Federal agency to which law enforcement support or support to a national special security event is provided by National Guard personnel performing duty under section 502(f) of title 32 to reimburse the Department of Defense for the costs of that support, notwithstanding any other provision of law. No other provision of this chapter shall apply to such support.
(2) Any funds received by the Department of Defense under this subsection as reimbursement for support provided by personnel of the National Guard shall be credited, at the election of the Secretary of Defense, to the following:
(A) The appropriation, fund, or account used to fund the support.
(B) The appropriation, fund, or account currently available for reimbursement purposes.
(c) An agency to which support is provided under this chapter or section 502(f) of title 32 is not required to reimburse the Department of Defense for such support if the Secretary of Defense waives reimbursement. The Secretary may waive the reimbursement requirement under this subsection if such support—
(1) is provided in the normal course of military training or operations; or
(2) results in a benefit to the element of the Department of Defense or personnel of the National Guard providing the support that is substantially equivalent to that which would otherwise be obtained from military operations or training.