The Army Reserve is the federal component of the US Army's Reserve component, which, along with the National Guard, make up the entire Reserve component of the US Army. These two Reserve components are joined by the full-time Active Duty soldiers to make up the entire US Army.
The difference between the Army Reserve and the Army National Guard is in the level of government to which they usually answer to - the Army Reserve answers only to the federal government, while the National Guard answers to the state government (except when called into federal service by the President or an act of law). This unique arrangement dates back to the founding of our country, when state governments were wary of a strong federal army, and established state militias as a response.
In addition to the National Guard vs. Reserve question, a lot of confusion comes from the different Reserve classifications. Here is a brief breakdown of the Reserve categories:
- Ready Reserve: members of the Reserve and National Guard organized into units, able to be recalled to active duty in time of war or national emergency. It has three subcategories.
- Selected Reserve: units in the Ready Reserve declared essential by their services and the Chairman of the Joint Chiefs of Staff. These units have priority over other Reserve units.
- Individual Ready Reserve: A pool of individuals who have had training, completed time either in an Active Duty or Selected Reserve component and have a portion of their military commitment remaining.
- Inactive National Guard: National Guard personnel in inactive status in a Ready Reserve (not Selected Reserve) unit. They are required to muster once a year to train.
- Standby Reserve: personnel who maintain affiliation with National Guard who are either designated key civilian employees or have a temporary hardship/disability. They are not part of specific units and not required to undergo regular training, but are a last resort of skilled manpower to fill certain needed gaps.
- Retired Reserve: Reserve personnel who receive retired pay based on service, Reserve personnel who could receive retired pay but have not reached the age of 60 or elected for discharge, and other Reservists under certain conditions