	Background

The size of the Armed Forces is a topic of perennial congressional interest and debate, as each year Congress sets 
minimum and maximum strength levels for the active components (AC); and maximum strength levels for the reserve components (RC). The House and Senate versions of the National Defense Authorization Act (NDAA) for FY2017 authorized differing levels for active duty personnel in each of the services, but these authorizations diverge most significantly with respect to the Army. This report provides an overview of active duty Army personnel strength changes in recent years, highlights the factors which have contributed to these diverging approaches in the respective NDAAs, and outlines some factors which Congress may consider. For FY2017, the Administration proposed lowering the Army's end strength to 460,000. The Senate version of the FY2017 National Defense Authorization Act approved Army end strength identical to the Administration request, while the House version approved Army end strength of 480,000. These include the strategic environment, the role of the Army within this environment, how the Army might use additional end strength, the results of a congressionally directed study on the future of the Army, and the constraints of the Budget Control Act of 2011. Roles for the U.S. Army? National Commission on the Future of the Army (NCFA)

Title XVII of the FY2015 NDAA established an independent commission to study Army strength and force structure and directed it to
... undertake a comprehensive study of the structure of the Army, and policy assumptions related to the size and force mixture of the Army, in order— 
(A) to make an assessment of the size and force mixture of the active component of the Army and the reserve components of the Army; and 
(B) to make recommendations on the modifications, if any, of the structure of the Army related to current and anticipated mission requirements for the Army at acceptable levels of national risk and in a manner consistent with available resources and anticipated future resources. Key Questions

The Department of Defense plans further reductions in the size of the Army, proposing a FY2018 end strength of 450,000. To reconcile competing interpretations and judgments about the proper size of the Army, Congress may gather additional information from the Army and outside experts. What additional resources are associated with end strength increases?
Article I, Section 8, of the U.S. Constitution vests Congress with broad powers over the Armed Forces, including the power "To raise and support Armies" and "To provide and maintain a Navy." As such, the size of the Armed Forces is a topic of perennial congressional interest and debate. Congress annually sets minimum and maximum strength levels for the active components and maximum strength levels for the reserve components.
The House and Senate versions of the National Defense Authorization Act (NDAA) for FY2017 authorized differing levels for active duty personnel in each of the services, but these authorizations diverge most significantly with respect to the Army. The Senate version of the FY2017 National Defense Authorization Act approved Army end strength of 460,000 soldiers, while the House version approved an Army end strength of 480,000. The Senate figure represents a decrease of 15,000 soldiers in comparison to the Army's FY2016 end strength of 475,000, while the House figure represents an increase of 5,000.
Congress's decision about the size of the Army for FY2017 will likely hinge on how it reconciles competing interpretations and judgments about key issues, including
the current and emerging strategic environment; the role of the Army in advancing national security interests within that environment; how any additional end strength would be used by the Army; the results of a congressionally directed study on the future of the Army; and the trade-offs associated with various options to fund additional strength in the context of budgetary constraints.
In addition to the decision for FY2017, the debate about the size of the Army may well continue into the next Congress, as the Department of Defense plans further reductions in the size of the Army, proposing FY2018 end strength of 450,000. There will also be a new President in January, and his or her policy priorities may revise the contours of this debate.
This report provides an overview of active duty Army personnel strength changes in recent years, outlines the different end strength authorizations in the House and Senate versions of the FY2017 NDAA, highlights the perspectives which have contributed to these diverging approaches in the respective NDAAs, and outlines some factors which Congress may consider as it determines the appropriate size for the Army.