Reserve component

The reserve components of the United States Armed Forces are military organizations whose members generally perform a minimum of 39 days of military duty per year and who augment the active duty (or full-time) military when necessary. The reserve components are also referred to collectively as the National Guard and Reserve.

According to 10 U.S.C. § 10102, the purpose of each reserve component is to provide trained units and qualified persons available for active duty in the armed forces, in time of war or national emergency, and at such other times as the national security may require, to fill the needs of the armed forces whenever, during and after the period needed to procure and train additional units and qualified persons to achieve the planned mobilization, more units and persons are needed than are in the regular components.

The seven reserve components of the U.S. military are:

The civilian auxiliaries of the U.S. military are not considered reserve components of the respective Services, but do serve as force multipliers:

These auxiliaries are generally excluded from direct combat roles. However, during World War II, members of the Civil Air Patrol and the Coast Guard Auxiliary were sometimes armed. Civil Air Patrol pilots engaged in anti-submarine patrols, armed with bombs, and engaged over 100 U-boats, sinking two. Members of the Coast Guard Auxiliary could volunteer as "temporary reservists," for duty as armed port security and harbor patrol officers.

While merchant mariners were usually not armed, armed Navy or Coast Guard crews were frequently embarked on Merchant Marine vessels. U-boats preying on allied shipping in the Atlantic made service as a merchant mariner extremely hazardous. In the 1980s, some Merchant Mariners who had sailed during World War II, were granted veteran benefits.

Additionally, under the U.S. Constitution, each State (or Commonwealth), may have additional organized militia, such as the various State guards and State naval militias. These State forces are not normally considered to be reserve components because they are not federal forces and under the jurisdiction and command of each state's respective governor, even though they perform a military function. Nearly every state has laws authorizing state defense forces, and 22 states, plus the Commonwealth of Puerto Rico, have active SDFs with different levels of activity, support, and strength. State defense forces generally operate with emergency management and homeland security missions. These forces are trained and equipped to perform specialized roles such as search and rescue, maritime patrols, augmenting state police or National Guard military police in a law enforcement role, or emergency management response. These forces may be armed or equipped, and have powers of arrest, as each State requires, and as State forces are not subject to the limitations of the Posse Comitatus laws governing Federal military forces' engaged in law enforcement duties.

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