US Code
CHAPTER 39— ACTIVE DUTY
§ 688a. Retired members: temporary authority to order to active duty in high-demand, low-density assignments

(a) Authority.—The Secretary of a military department may order to active duty a retired member who agrees to serve on active duty in an assignment intended to alleviate a high-demand, low-density military capability or in any other specialty designated by the Secretary as critical to meet wartime or peacetime requirements. Any such order may be made only with the consent of the member ordered to active duty and in accordance with an agreement between the Secretary and the member.
(b) Duration.—The period of active duty of a member under an order to active duty under subsection (a) shall be specified in the agreement entered into under that subsection.
(c) Limitation.—No more than a total of 1,000 members may be on active duty at any time under subsection (a).
(d) Relationship to Other Authority.—The authority to order a retired member to active duty under this section is in addition to the authority under section 688 of this title or any other provision of law authorizing the Secretary concerned to order a retired member to active duty.
(e) Inapplicability of Certain Provisions.—Retired members ordered to active duty under subsection (a) shall not be counted for purposes of section 688 or 690 of this title.
(f) Expiration of Authority.—A retired member may not be ordered to active duty under this section outside a period as follows:(1) The period beginning on December 2, 2002, and ending on December 31, 2011.
(2) The period beginning on the date of the enactment of the National Defense Authorization Act for Fiscal Year 2018 and ending on December 31, 2022.
(g) Exceptions During Periods of War or National Emergency.—The limitations in subsections (c) and (f) shall not apply during a time of war or of national emergency declared by Congress or the President.
(h) High-Demand, Low-Density Military Capability Defined.—In this section, the term “high-demand, low-density military capability” means a combat, combat support or service support capability, unit, system, or occupational specialty that the Secretary of Defense determines has funding, equipment, or personnel levels that are substantially below the levels required to fully meet or sustain actual or expected operational requirements set by regional commanders.

Structure US Code