American Military History, Volume 2 by Richard W. Stewart

Promoting the integration of the Regular Army, National Guard, and Organized Reserves by establishing uniformity in training and pro- fessional standards was one of the major purposes of the National De- fense Act of 1920. While falling considerably short of fully realizing that goal, the new Army structure did foster an unprecedented amount of military training for the reserve components. This training brought the regular out of his traditional isolation from the civilian community and acquainted large numbers of National Guard and Organized Reserve personnel with the problems and views of professional soldiers. Reserve component units and the groups in training that contributed to their ranks had an average strength of about 400,000 between the wars. The Reserve Component Training Program would result in an orderly and effective mobilization of the National Guard and Organized Reserve into the Active Army during 1940 and 1941.

The absorption of the National Guard into the Regular Army dur- ing World War I originally left the states without any Guard units af- ter the Armistice. The National Defense Act of 1920 contemplated a National Guard of 436,000, but its actual interwar strength stabilized at about 180,000. This force relieved the Regular Army of any duty in curbing domestic disturbances within the states from the summer of 1921 until 1941 and stood ready for immediate induction into the Active Army whenever necessary. The War Department, in addition to supplying regular training officers and large quantities of surplus World War I materiel, applied about one-tenth of its military budget to the support of the Guard in the years between the wars. Guardsmen en- gaged in forty-eight armory drills and fifteen days of field training each year. Though not comparable to Regular Army units in readiness for war, by 1939 the increasingly federalized Guard was better trained than it had been when mobilized for duty on the Mexican border in 1916. Numerically, the National Guard was the largest component of the Army of the United States between 1922 and 1939.