CRS INSIGHT Prepared for Members and Committees of Congress
Under 10 U.S.C. §115(a), Congress sets the maximum size (i.e., end-strength) of the active and reserve components of the Armed Forces annually, typically in a National Defense Authorization Act (NDAA). Congress is also responsible for appropriating funds for the pay and benefits of these personnel. End- strength specifically refers to the actual number of personnel in a branch on the last day of the fiscal year (i.e., on September 30). The proposed end-strength figures in an FY2025 NDAA would be for September 30, 2025. Congress also periodically sets minimum end strength levels for the Armed Forces, which may be identical to or lower than the authorized end strength. While Congress authorizes minimum and maximum end-strengths, each military service manages its force, through recruiting and retention efforts, to achieve an actual end-strength.
Typically, this actual end-strength falls within the congressionally authorized minimum and maximum end-strengths. However, there are circumstances in which the actual end-strength may fall outside the authorized range. For example, under 10 U.S.C. §115(c), the Secretary of Defense may increase the end- strength of any of the services above the authorized end-strength by up to 2%. Recruiting and retention shortfalls may cause one or more of the services to fall below their minimum authorized strength.
Congress sets annual end-strength figures for the active component of the Armed Forces—comprised of personnel serving in a full-time capacity—and for the reserve component. The reserve component provides “trained units and qualified persons available for active duty in the armed forces, in time of war or national emergency, and at such other times as the national security may require, to fill the needs of the armed forces whenever...more units and persons are needed than are in the regular components.” (10. U.S.C. § 10102).
The Secretary of Defense is required by law (10 U.S.C. §113a(b)(2)) to submit end-strength requests for all branches of the reserve component in an annual request to Congress. Congress is not bound by these requests, but has authorized end-strengths similar to the Pentagon’s requested numbers.
The reserve component consists of the reserve forces of the Army, Navy, Air Force, Marine Corps, and Coast Guard, as well as the Army National Guard (ARNG) and Air National Guard (ANG). The Space
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Force does not have a reserve component. It is a single-component Armed Force with personnel serving in an inactive or active-duty status (10 U.S.C. §20001). The National Guard (ANG and ARNG) may be mobilized under federal or state authority, and performs homeland security missions that include responding to civil unrest and natural disasters, as well as guarding domestic airspace.
Congress varies the authorized end-strengths over time in response to factors such as national security priorities, budget constraints, and recruitment challenges. It has lowered authorized reserve component end-strengths year over year since 2009 (see Figure 1), as U.S. commitments in Iraq and Afghanistan diminished and the Services faced growing recruitment challenges.
In S.Rept. 118-58, the Senate Armed Services Committee (SASC) stated that it chose to recommend lower end-strengths than requested because “legislating unreachable end-strength numbers would set the military services up for failure” by forcing them to lower recruiting standards in pursuit of unrealistic manpower quotas. It remains unclear whether incremental reductions in previous years may have stemmed in part from this concern.
Figure 1. Selected Reserve Component Authorized End-Strength FY2001–FY2025 Request
Figure is interactive in the HTML version of this Insight.
Source: CRS analysis of Congress for FY2001–FY2024 data. FY2025 data from President’s Budget Request.
Each reserve component force has seen declines from FY2001 to FY2024. The total decline is 11.6 %, while the Navy Reserve has seen the highest reduction of 35.1% (See Table 1).
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Table 1. Percent Change in Selected Reserve Authorized End-Strength, FY2001-FY2025
Request
Army
National
Guard
Army
Reserve
Navy
Reserve
Marine
Corps
Reserve
Air National
Guard
Air Force
Reserve
Total
Reserve
Component
-7.3% -14.4% -35.1% -17.8% -0.3% -9.9% -11.6%
Source: Congress.gov for FY2001-FY2024 data; FY2025 data from President’s Budget Request.
Table 2. Comparison of FY2024 Enacted and FY2025 President’s Budget Request for
Selected Reserve Component End-Strength
Service
FY2024 Enacted (P.L. 118-31)
FY2025 President’s
Budget Request
Difference Between
FY2025 Request and
FY2024 Enacted
Army National Guard 325,000 325,000 0
Army Reserve 174,800 175,800 +1,000
Navy Reserve 57,200 57,700 +500
Marine Corps Reserve 32,000 32,500 +500
Air National Guard 105,000 107,700 +2,700
Air Force Reserve 69,600 67,000 -2,600
Total 763,600 765,700 +2,100
Source: Congress.gov, Office of the Under Secretary of Defense (Comptroller).
The Biden Administration’s FY2025 budget increases requested end-strengths for the Army Reserve, Navy Reserve, Marine Corps Reserve, and Air National Guard from FY2024 enacted levels. It lowers requested end-strength for the Air Force Reserve and maintains the FY2024 end-strength of the Army National Guard (see Table 2). Its requests represent a total increase of 2,100 over FY2024 enacted levels.
Table 3. Comparison of FY2025 NDAA Selected Reserve Component End-Strength
Provisions
Service
FY2025 President’s
Budget Request
House-passed H.R. 8070
Senate Armed Services-reported S. 4638
Notable
Differences
Army National Guard 325,000 325,000 325,000 None
Army Reserve 175,800 175,800 175,800 None
Navy Reserve 57,700 57,700 57,700 None
Marine Corps Reserve
32,500 32,500 32,500 None
Air National Guard 107,700 107,700 108,300 Senate committee version authorizes 600 more personnel than requested.
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Service
FY2025 President’s
Budget Request
House-passed H.R. 8070
Senate Armed Services-reported S. 4638
Notable
Differences
Air Force Reserve 67,000 67,000 67,000 None
Total 765,700 765,700 766,300 Senate committee version +600
Source: Congress.gov, Department of Defense Office of the Comptroller.
The House has passed and the Senate is considering different versions of an FY2025 National Defense Authorization Act. The House-passed version, H.R. 8070, proposes an authorized end-strength that is identical to the President’s budget request. The SASC-reported version (S. 4638) proposes similar authorized end-strength, with 600 more personnel for the Air National Guard (see Table 3). S.Rept. 118- 188, accompanying the SASC-reported version of an FY2025 NDAA, explained that the increase in the Air National Guard end-strength is intended “to offset any reductions that may occur as a result of transferring units and personnel from the Air National Guard to the Space Force” as authorized under Section 515 of the NDAA.
Congress may consider several actions:
• Absolute Increase: Congress may assess whether present and future security challenges require a larger reserve force, and consider whether or not to authorize an absolute increase in the number of reserve component personnel. Such an action may increase the Armed Forces’ capacity, with potentially higher costs.
• Absolute Decrease: Congress could assess whether the security environment does not justify a reserve force of the present size, and consider whether or not to authorize a reduction in the absolute number of reserve component personnel. Such a reduction may reduce costs, but may also reduce the Armed Forces’ capacity.
• Shift Active End-Strength to Reserve Component: Congress could assess whether U.S. security objectives would be better served by a larger reserve component, and could consider whether or not to shift end-strength from the active to the reserve component. Such a shift could create a force that may cost less to maintain, but also may be slower to deploy. Such an approach may also reduce the readiness of the active component.
• Shift Reserve End-Strength to Active Component: Congress could assess whether U.S. security objectives would be better served by a larger active component, and could consider whether or not to shift end-strength from the reserve to the active component. Such a shift could create a force that may cost more to maintain, but also may be quicker to deploy. It may also increase the tempo of active component operations and thereby reduce retention.
• Maintain Current End-Strength: Congress may decide that current end-strength meets U.S. security objectives and make no changes.
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IN12448 · VERSION 1 · NEW
Nicholas M. Munves Analyst in U.S Defense Policy
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United States. Any CRS Report may be reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you wish to copy or otherwise use copyrighted material.