National Guard (United States)

In the United States, there are Army and Air Force reserve components respectively called the [Army] National Guard and Air National Guard; "National Guard" without qualifiers is usually assumed to mean the Army Guard. Guard forces are under a dual command: state governors when not "Federalized", or part of the U.S. military when they are. There are no Naval or Marine equivalents.

Non-federalized Guard units carry out domestic emergency operations under the control of governors, such as responding to storms and forest fires. They may also respond to riots and civil disturbances, although the law becomes more complex here. In some cases, non-federalized units may respond outside the state under governor-to-governor arrangements with state-to-state reimbursement; the California and Oregon Guards, for example, responded to Hurricane Katrina in Louisiana.

From the national perspective, they are part of the Reserve Components, which also includes the Army, Navy, Air Force, and Marine Corps Reserves, which are always under Federal control. The National Guard Bureau, which funds and oversees both National Guard programs, is administratively part of the Department of the Army.

Especially with the duration of the Iraq War and the reductions in Federal forces, Guard forces have been in combat roles longer than in any conflict since the Second World War.