	Issue Overview

The Army is composed of both an Active Component (AC) and a Reserve Component (RC). The RC consists primarily of soldiers who serve part-time but who can be ordered to full-time duty. The Army's RC is made up of both the Army National Guard (ARNG) and the United States Army Reserve (USAR). AC/RC force mix refers to the distribution of units among the active and reserve components of the armed forces. Debates over AC/RC mix center on whether to shift force structure between the AC and the RC and, if so, what types of units to shift. Although specific force mix recommendations can be nuanced, policy advocates generally divide between those who favor a stronger AC emphasis and those who favor a stronger RC emphasis. In the contemporary debate, those who favor a stronger RC emphasis believe that RC units can replace a portion of AC force structure while saving money. The congressional role in AC/RC force mix is most obvious in its authorization of end strengths for the active and reserve components of each Service, but congressional authority concerning AC/RC mix is much broader than that. The Constitution provides Congress with broad powers over the armed forces, including the power to "to raise and support Armies," "to provide and maintain a Navy," "to make Rules for the Government and Regulation of the land and naval Forces" and "to provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States.... " On the basis of its constitutional authority, Congress authorizes and appropriates funds for the AC and RC on an annual basis and sets end strengths limiting the size of the respective forces. It proposes that RC forces make up 54.1% of the Army by FY2017, in comparison to 53.6% just before the September 11 attacks and 49.1% when the Army was at its peak size during the Iraq and Afghanistan wars (2010). This proposal would also include a shift of the relative proportion of brigade combat teams (BCTs) towards the ARNG, although the Army's Aviation Restructuring Initiative proposes moving attack helicopters (AH-64 Apaches) from the USAR and ARNG to the AC to replace retiring armed reconnaissance helicopters (OH-58D). The Active Component (AC)

The Army's active component consists of soldiers who are in the Army as their full-time occupation. This proposal, which has generated a great deal of discussion, is further discussed in Appendix A .

	AC/RC Mix: Considerations for Congress

Determining the appropriate mix of AC and RC forces is complex, with many factors affecting the process. Of these, utilization, readiness, effectiveness, cost, and risk are generally considered the major elements in developing the AC/RC force mix. Others believe that certain RC forces—particularly larger direct combat units and higher echelon headquarters—are not as capable as AC forces without substantial additional preparation; cannot respond to a crisis as rapidly as AC forces; and cannot be used with the same frequency and duration as AC forces due to policy limitations. Those who take this perspective believe that replacing too many or certain types of AC units with RC units could reduce the Army's ability to respond rapidly to an overseas crisis and sustain operations over time; or could require too much additional RC funding and training time to make it cost-effective. As Congress considers the future AC/RC mix for the Army, there are several approaches it may wish to consider. They are not necessarily mutually exclusive; Congress could elect to pursue some combination of the following options:
Support Administration proposals on what the proper mix of Army AC and RC units should be; Gather additional information on key factors that contribute to AC/RC mix decisions; Directly adjust AC/RC mix; and/or Influence AC/RC mix by adjusting factors that contribute to mix decisions. Each of these authorities is detailed below.
The Army is composed of both an Active Component (AC) and a Reserve Component (RC). The AC consists of soldiers who are in the Army as their full-time occupation. The RC is composed primarily of soldiers who serve part-time but who can be ordered to full-time duty. The Army's RC is made up of both the Army National Guard (ARNG) and the United States Army Reserve (USAR). AC/RC force mix refers to the distribution of units between the active and reserve components of the armed forces.
The congressional role in AC/RC force mix is most obvious in its authorization of end strengths for the active and reserve components of each Service. Congressional authority concerning AC/RC mix, however, is much broader than that, as the Constitution provides Congress with broad powers over the armed forces, including the power to "to raise and support Armies," "to provide and maintain a Navy," "to make Rules for the Government and Regulation of the land and naval Forces" and "to provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States.... "
Debates over AC/RC mix center on whether or not to shift force structure between the AC and the RC and, if so, what types of units to shift. Although specific force mix recommendations can be nuanced, policy advocates generally divide between those who favor a stronger AC emphasis and those who favor a stronger RC emphasis. In the contemporary debate, those who favor a stronger RC emphasis believe that RC units, if properly trained and equipped, are as capable as their AC counterparts while costing less. Thus, they argue that RC units can replace a portion of AC force structure while saving money. Those who favor a stronger AC emphasis believe that certain RC forces—particularly larger direct combat units and higher echelon headquarters—are not as capable as AC forces without substantial additional preparation; cannot respond to a crisis as rapidly as AC forces; and cannot be used with the same frequency and duration as AC forces due to policy limitations. Those who take this perspective believe that replacing too many or certain types of AC units with RC units could reduce the Army's ability to respond rapidly to an overseas crisis and sustain operations over time, or could require too much additional RC funding and training time to make such an approach cost-effective.
Given the nation's current fiscal situation, the contemporary debate has shifted somewhat in favor of a higher ratio of RC forces. For example, in its FY2015 budget request, the Administration proposes that RC forces make up 54.1% of the Army by FY2017, in comparison to 53.6% just before the September 11 attacks and 49.1% when the Army was at its peak size during the Iraq and Afghanistan wars (2010). This proposal would also include a shift of the relative proportion of brigade combat teams (BCTs) towards the ARNG, although the Army's Aviation Restructuring Initiative proposes moving attack helicopters from the USAR and ARNG to the AC.
Determining the appropriate mix of AC and RC forces is complex, with many factors affecting the process. Of these, utilization, readiness, effectiveness, cost, and risk are generally considered the major elements in developing the AC/RC force mix. Each of these factors is described in some detail in this report, along with questions for further investigation. As Congress considers the future AC/RC mix for the Army, it may wish to consider several approaches, including supporting Administration proposals on AC/RC mix; gathering additional information on key factors which contribute to AC/RC mix decisions; directly altering AC/RC mix; and influencing AC/RC mix by adjusting factors that contribute to mix decisions.