((a)) ** .—** The Secretary of Defense, upon the request of the Attorney General, may provide assistance in support of Department of Justice activities relating to the enforcement of section 175, 229, or 2332a of title 18 during an emergency situation involving a weapon of mass destruction. Department of Defense resources, including personnel of the Department of Defense, may be used to provide such assistance if—

((1)) the Secretary of Defense and the Attorney General jointly determine that an emergency situation exists; and

((2)) the Secretary of Defense determines that the provision of such assistance will not adversely affect the military preparedness of the United States.

((b)) ** .—** In this section, the term “emergency situation involving a weapon of mass destruction” means a circumstance involving a weapon of mass destruction—

((1)) that poses a serious threat to the interests of the United States; and

((2)) in which—

((A)) civilian expertise and capabilities are not readily available to provide the required assistance to counter the threat immediately posed by the weapon involved;

((B)) special capabilities and expertise of the Department of Defense are necessary and critical to counter the threat posed by the weapon involved; and

((C)) enforcement of section 175, 229, or 2332a of title 18 would be seriously impaired if the Department of Defense assistance were not provided.

((c)) ** .—** The assistance referred to in subsection (a) includes the operation of equipment (including equipment made available under section 372  of this title) to monitor, contain, disable, or dispose of the weapon involved or elements of the weapon.

((d)) ** .—**

((1)) The Secretary of Defense and the Attorney General shall jointly prescribe regulations concerning the types of assistance that may be provided under this section. Such regulations shall also describe the actions that Department of Defense personnel may take in circumstances incident to the provision of assistance under this section.

((2))

((A)) Except as provided in subparagraph (B), the regulations may not authorize the following actions:

((i)) Arrest.

((ii)) Any direct participation in conducting a search for or seizure of evidence related to a violation of section 175, 229, or 2332a of title 18.

((iii)) Any direct participation in the collection of intelligence for law enforcement purposes.

((B)) The regulations may authorize an action described in subparagraph (A) to be taken under the following conditions:

((i)) The action is considered necessary for the immediate protection of human life, and civilian law enforcement officials are not capable of taking the action.

((ii)) The action is otherwise authorized under subsection (c) or under otherwise applicable law.

((e)) ** .—** The Secretary of Defense shall require reimbursement as a condition for providing assistance under this section to the extent required under section 377  of this title.

((f)) ** .—**

((1)) Except to the extent otherwise provided by the Secretary of Defense, the Deputy Secretary of Defense may exercise the authority of the Secretary of Defense under this section. The Secretary of Defense may delegate the Secretary’s authority under this section only to an Under Secretary of Defense or an Assistant Secretary of Defense and only if the Under Secretary or Assistant Secretary to whom delegated has been designated by the Secretary to act for, and to exercise the general powers of, the Secretary.

((2)) Except to the extent otherwise provided by the Attorney General, the Deputy Attorney General may exercise the authority of the Attorney General under this section. The Attorney General may delegate that authority only to the Associate Attorney General or an Assistant Attorney General and only if the Associate Attorney General or Assistant Attorney General to whom delegated has been designated by the Attorney General to act for, and to exercise the general powers of, the Attorney General.

((g)) ** .—** Nothing in this section shall be construed to restrict any executive branch authority regarding use of members of the armed forces or equipment of the Department of Defense that was in effect before .