10 U.S.C. § 115

(a) Active-Duty, Selected Reserve, and Space Force End Strengths To Be Authorized by Law .— Congress shall authorize personnel strength levels for each fiscal year for each of the following: (1) The end strength for the Army, Navy, Air Force, and Marine Corps for (A) active-duty personnel who are to be paid from funds appropriated for active-duty personnel unless on active duty pursuant to subsection (b), and (B) active-duty personnel and full-time National Guard duty personnel who are to be paid from funds appropriated for reserve personnel unless on active duty or full-time National Guard duty pursuant to subsection (b). (2) The end strength for the Selected Reserve of each reserve component of the armed forces. (3) The end strength for the Space Force for members in space force active status. (b) Certain Reserves on Active Duty To Be Authorized by Law .— (1) Congress shall annually authorize the maximum number of members of a reserve component permitted to be on active duty or full-time National Guard duty at any given time who are called or ordered to— (A) active duty under section 12301(d) of this title for the purpose of providing operational support, as prescribed in regulation issued by the Secretary of Defense; (B) full-time National Guard duty under section 502(f)(1)(B) of title 32 for the purpose of providing operational support when authorized by the Secretary of Defense; (C) active duty under section 12301(d) of this title or full-time National Guard duty under section 502(f)(1)(B) of title 32 for the purpose of preparing for and performing funeral honors functions for funerals of veterans under section 1491 of this title ; (D) active duty or retained on active duty under sections 12301(g) of this title while in a captive status; or (E) active duty or retained on active duty under 12301(h) or 12322 of this title for the purpose of medical evaluation or treatment. (2) A member of a reserve component who exceeds either of the following limits shall be included in the strength authorized under subparagraph (A) or subparagraph (B), as appropriate, of subsection (a)(1): (A) A call or order to active duty or full-time National Guard duty that specifies a period greater than three years. (B) The cumulative periods of active duty and full-time National Guard duty performed by the member exceed 1825 days in the previous 2190 days. (3) In determining the period of active service under paragraph (2), the following periods of active service performed by a member shall not be included: (A) All periods of active duty performed by a member who has not previously served in the Selected Reserve of the Ready Reserve. (B) All periods of active duty or full-time National Guard duty for which the member is exempt from strength accounting under paragraphs (1) through (8) of subsection (i). (4) As part of the budget justification materials submitted by the Secretary of Defense to Congress in support of the end strength authorizations required under subparagraphs (A) and (B) of subsection (a)(1) for fiscal year 2009 and each fiscal year thereafter, the Secretary shall provide the following: (A) The number of members, specified by reserve component, authorized under subparagraphs (A) and (B) of paragraph (1) who were serving on active duty or full-time National Guard duty for operational support beyond each of the limits specified under subparagraphs (A) and (B) of paragraph (2) at the end of the fiscal year preceding the fiscal year for which the budget justification materials are submitted. (B) The number of members, specified by reserve component, on active duty for operational support who, at the end of the fiscal year for which the budget justification materials are submitted, are projected to be serving on active duty or full-time National Guard duty for operational support beyond such limits. (C) The number of members, specified by reserve component, on active duty or full-time National Guard duty for operational support who are included in, and counted against, the end strength authorizations requested under subparagraphs (A) and (B) of subsection (a)(1). (D) A summary of the missions being performed by members identified under subparagraphs (A) and (B). (c) Limitation on Appropriations for Military Personnel .— No funds may be appropriated for any fiscal year to or for— (1) the use of active-duty personnel or full-time National Guard duty personnel of any of the armed forces (other than the Coast Guard) unless the end strength for such personnel of that armed force for that fiscal year has been authorized by law; (2) the use of the Selected Reserve of any reserve component of the armed forces unless the end strength for the Selected Reserve of that component for that fiscal year has been authorized by law; (3) the use of members of the Space Force in space force active status unless the end strength for the Space Force for that fiscal year for members in space force active status has been authorized by law; or (4) the use of reserve component personnel to perform active duty or full-time National Guard duty under subsection (b) unless the strength for such personnel for that reserve component for that fiscal year has been authorized by law. (d) Military Technician (Dual Status) End Strengths To Be Authorized by Law .— Congress shall authorize for each fiscal year both the minimum end strength for non-temporary military technicians (dual status) and the end strength for temporary military technicians (dual status) for each reserve component of the Army and Air Force. Funds available to the Department of Defense for any fiscal year may not be used for the pay of a military technician (dual status) during that fiscal year unless the technician fills a position that is within the number of such positions authorized by law for that fiscal year for the reserve component of that technician. This subsection applies without regard to section 129 of this title . In each budget submitted by the President to Congress under section 1105 of title 31 , the minimum end strength for non-temporary military technicians (dual status), and the end strength for temporary military technicians (dual status), requested for each reserve component of the Army and Air Force shall be specifically set forth. (e) End-of-Quarter Strength Levels .— (1) The Secretary of Defense shall prescribe and include in the budget justification documents submitted to Congress in support of the President’s budget for the Department of Defense for any fiscal year the Secretary’s proposed end-of-quarter strengths for each of the first three quarters of the fiscal year for which the budget is submitted, in addition to the Secretary’s proposed fiscal-year end-strengths for that fiscal year. Such end-of-quarter strengths shall be submitted for each category of personnel for which end strengths are required to be authorized by law under subsection (a) or (d). The Secretary shall ensure that resources are provided in the budget at a level sufficient to support the end-of-quarter and fiscal-year end-strengths as submitted. (2) (A) After annual end-strength levels required by subsections (a) and (d) are authorized by law for a fiscal year, the Secretary of Defense shall promptly prescribe end-of-quarter strength levels for the first three quarters of that fiscal year applicable to each such end-strength level. Such end-of-quarter strength levels shall be established for any fiscal year as levels to be achieved in meeting each of those annual end-strength levels authorized by law in accordance with subsection (a) (as such levels may be adjusted pursuant to subsection (f)) and subsection (d). (B) At least annually, the Secretary of Defense shall establish for each of the armed forces (other than the Coast Guard) the maximum permissible variance of actual strength for an armed force at the end of any given quarter from the end-of-quarter strength established pursuant to subparagraph (A). Such variance shall be such that it promotes the maintaining of the strength necessary to achieve the end-strength levels authorized in accordance with subsection (a) (as adjusted pursuant to subsection (f)) and subsection (d). (3) Whenever the Secretary establishes an end-of-quarter strength level under subparagraph (A) of paragraph (2), or modifies a strength level under the authority provided in subparagraph (B) of paragraph (2), the Secretary shall notify the Committee on Armed Services of the Senate and the Committee on Armed Services of the House of Representatives of that strength level or of that modification, as the case may be. (f) Authority for Secretary of Defense Variances for Active-Duty and Selected Reserve Strengths .— Upon determination by the Secretary of Defense that such action is in the national interest, the Secretary may— (1) vary the end strength authorized pursuant to subsection (a)(1)(A) for a fiscal year for any of the armed forces by a number equal to not more than 3 percent of that end strength; (2) vary the end strength authorized pursuant to subsection (a)(1)(B) for a fiscal year for any of the armed forces by a number equal to not more than 3 percent of that end strength; (3) vary the end strength authorized pursuant to subsection (a)(2) for a fiscal year for the Selected Reserve of any of the reserve components by a number equal to not more than 3 percent of that end strength; and (4) vary the maximum strength authorized pursuant to subsection (b)(1) for a fiscal year for certain reserves on active duty for any of the reserve components by a number equal to not more than 10 percent of that strength. (g) Authority for Service Secretary Variances for Active-duty and Selected Reserve End Strengths .— (1) Upon determination by the Secretary of a military department that such action would enhance manning and readiness in essential units or in critical specialties or ratings, the Secretary may— (A) vary the end strength pursuant to subsection (a)(1)(A) for a fiscal year for the armed force or forces under the jurisdiction of that Secretary by a number not equal to more than 2 percent of such authorized end strength; (B) vary the end strength pursuant to subsection (a)(1)(B) for a fiscal year for the armed force or forces under the jurisdiction of that Secretary by a number not equal to more than 2 percent of such authorized end strength; and (C) vary the end strength pursuant to subsection (a)(2) for a fiscal year for the Selected Reserve of the reserve component of the armed force or forces under the jurisdiction of that Secretary by a number equal to not more than 2 percent of such authorized end strength. (2) Any variance under paragraph (1)(A) of the end strength for an armed force for a fiscal year shall be counted as part of the variance for that armed force for that fiscal year authorized under subsection (f)(1). Any variance under paragraph (1)(B) of the end strength for the Selected Reserve of a reserve component of an armed force for a fiscal year shall be counted as part of the variance for that Selected Reserve for that fiscal year authorized under subsection (f)(3). (3) The Secretary of the military department concerned shall promptly notify the congressional defense committees if such Secretary exceeds a variance under paragraph (1), and at least once every 90 days thereafter for so long as such end strength is outside such variance. Each such notification shall include the following: (A) Modified projected end strengths for active and reserve components of the armed force or forces for which such Secretary exceeds such variance. (B) An identification of any budgetary effects projected as a result of such modified end strength projections. (C) An explanation of any effects on readiness resulting from such modified end strength projections. (h) Adjustment When Coast Guard is Operating as a Service in the Navy .— The authorized strength of the Navy under subsection (a)(1) is increased by the authorized strength of the Coast Guard during any period when the Coast Guard is operating as a service in the Navy. (i) Certain Personnel Excluded From Counting for Active-Duty End Strengths .— In counting personnel for the purpose of the end strengths authorized pursuant to subsection (a)(1), persons in the following categories shall be excluded: (1) Members of a reserve component ordered to active duty under section 12301(a) of this title . (2) Members of a reserve component in an active status ordered to active duty under section 12301(b) of this title . (3) Members of the Ready Reserve ordered to active duty under section 12302 of this title . (4) Members of the Selected Reserve of the Ready Reserve or members of the Individual Ready Reserve mobilization category described in section 10144(b) of this title ordered to active duty under section 12304 of this title . (5) Members of the National Guard called into Federal service under section 12406 of this title . (6) Members of the militia called into Federal service under chapter 13 of this title. (7) Members of the National Guard on full-time National Guard duty under section 502(f)(1)(A) of title 32 . (8) Members of reserve components on active duty for training or full-time National Guard duty for training. (9) Members of the Selected Reserve of the Ready Reserve on active duty to support programs described in section 1321(a) of the Department of Defense Cooperative Threat Reduction Act ( 50 U.S.C. 3711(a) ). (10) Members of the National Guard on active duty or full-time National Guard duty for the purpose of carrying out drug interdiction and counter-drug activities under section 112 of title 32 . (11) Members of a reserve component on active duty under section 10(b)(2) of the Military Selective Service Act (50 U.S.C. App. 460(b)(2)) 1 1 See References in Text note below. for the administration of the Selective Service System. (12) Members of the National Guard on full-time National Guard duty for the purpose of providing command, administrative, training, or support services for the National Guard Challenge Program authorized by section 509 of title 32 . (13) Members of the National Guard on full-time National Guard duty involuntarily and performing homeland defense activities under chapter 9 of title 32.