The Army of the United States is one of the four major service components of the United States Army (the others being the Regular Army, the United States Army Reserve and the Army National Guard of the United States),[1] but it has been inactive since the suspension of the draft in 1973 and the U.S. military's transition to a volunteer force.[2] Personnel serving in the United States Army during a major national emergency or armed conflict (either voluntarily or involuntarily) were enlisted or inducted into the Army of the United States without specifying service in a component. It also includes the "Retired Reserve." Those are retired soldiers who have reached the required years of creditable service, or creditable service and age; regardless of the component, or components they formerly served in.
The term "Army of the United States" or "Armies of the United States" is also the legal name of the collective land forces of the United States as prescribed by the United States Constitution.[3][4] In this concept, the term "Army of the United States" has been in use since at least 1841 as in the title General Regulations for the Army of the United States. Also included by Act of the 39th Congress (1866) were the U.S. Volunteers, persons holding a brevetted rank, and the U.S. Veteran Reserve Corps.