American Military History, Volume 2 by Richard W. Stewart

After many months of careful consideration, Congress passed a sweeping amendment to the National Defense Act of 1916. The Na- tional Defense Act of June 4, 1920, governed the organization and reg- ulation of the Army until 1950 as one of the most constructive pieces of military legislation ever adopted in the United States. It rejected the theory of an expansible Regular Army that Army leaders had urged since the days of John C. Calhoun. In its place the new defense act established the Army of the United States as an organization of three components: the standing Regular Army, the National Guard, and the Organized Reserves. That component consisted of the Officers' Reserve Corps and the Enlisted Reserve Corps, two distinct organizations. Each of the three Army components was to be so regulated in peacetime that it could contribute its appropriate share of troops in a war emergency.

The act acknowledged and authorized the historical practice of the United States: a standing peacetime Army too small to be expanded to meet the needs of a large war and reliance on a new force of citizen- soldiers when large-scale mobilizations were necessary. In contrast to earlier practice, training the National Guard and Organized Reserves became a major peacetime task of the Regular Army. To fulfill that mis- sion Congress authorized a maximum Regular Army officer strength of 17,726 officers, more than three times the prewar number. At least half the new career officers were to be chosen from among nonregulars who had served during the war. The act also required that officer promo- tions, except for doctors and chaplains, be made from a single list. That policy equalized opportunities for advancement throughout most of the Army. Congress authorized a maximum Regular Army enlisted strength of 280,000 men, but the actual enlisted and officer strengths would depend on the amount of money appropriated annually.