Army of the United States The Army of the United States is the official name for the conscription ( U . S . term : draft ) force of the United States Army that may be raised at the discretion of the United States Congress in the event of the United States entering into a major armed conflict . The Army of the United States was utilized in World War II , the Korean War , and the Vietnam War . History . World War II . The Army of the United States ( AUS ) was first established in February 1941 , in response to the looming threat of World War II . The Army of the United States saw a major expansion following the December 1941 attack on Pearl Harbor . The Army of the United States was considered a successor to the National Army , which had been founded to fight in World War I and had been disbanded in 1920 . The first officers of the Army of the United States were appointed from the ranks of the Regular Army . The standard practice for such officers was to hold a " permanent rank " within the Regular Army while holding a " temporary rank " for service in the Army of the United States . A typical situation would be a colonel in the Army of the United States holding the permanent rank of captain in the Regular Army . Another term for the Army of the United States rank was " Theater Rank , " held by officers who were deployed to the European Theater or serving in the Pacific . Promotions within the Army of the United States were sometimes very rapid and some officers rose as many as four to five ranks in the space of three to four years . Dwight Eisenhower , who served as General of the Army , rose from a colonel to five - star general in three years . Rank within the Army of the United States could also be revoked just as easily , however , with senior commanders who were relieved reverting to their permanent rank in the Regular Army . This was known as " loss of theater rank , " with some instances of generals returning to the United States , in disgrace or at least under a cloud , as colonels or majors . The enlisted force of the Army of the United States was made up of Regular Army professionals who , unlike their officer counterparts , did not hold rank in the Army of the United States but were considered as Regular Army only . Personnel enlisting in the United States Army could also choose to enlist as Regular Army , which would entail a greater service obligation . The draft forces of the U . S . Army were all Army of the United States personnel and were annotated by the abbreviation " AUS " in front of their service number s and in the " Component " block 5 on their discharge papers . Regular Army personnel were denoted by the abbreviations " RA . " In 1946 , with postwar demobilization , the Army of the United States was suspended , along with the draft . Officers from that point reverted to Regular Army rank and all enlisted personnel either were discharged from the Army of the United States or reenlisted in the Regular Army . The Army of the United States was reinstated during the Korean War but mainly was confined to the enlisted forces . Most officers of the Korean War held Regular Army rank only . Korean War . Upon its reinstatement for the Korean War , the Army of the United States only consisted of conscripts with the Regular Army , National Guard , and Army of the United States existing simultaneously in the same theater . The system of Service Numbers was as follows : For the Korean War , the Army of the United States changed its abbreviation to " US , " replacing the older " AUS . " Vietnam and beyond . The last use of the Army of the United States was during the Vietnam War , and it was disbanded after 1974 . Today , the only further use of the Army of the United States is on the retired officer rolls of the U . S . Army . In cases of senior personnel , the retired rolls may list their rank as " AUS Retired , " meaning that the rank they hold for retirement pay is higher than their permanent rank at the actual time of retirement . Army Reserve Officers who are retired from active duty by reason of longevity ( 20 years or more of active duty ) , and those Army Reserve Officers placed on the Permanent Disability Retired List are transferred to the Retired Reserve , and use the designation " Army of the United States , Retired . " ( Note : In recent years , by contrast , some Army Reserve Officers who are serving on active duty and are subsequently placed on the Permanent Disability Retired List have been designated " United States Army , Retired " by Department of the Army orders ) The Army Reserve and National Guard of the United States have never been incorporated into the Army of the United States , and have always been separate components . The Army National Guard is known by the service abbreviation " ARNG , " while the Army Reserve is referred to as " USAR . "