The United States National Guard is a significant component of the United States armed forces military reserve. The Militia Act of 1903, also known as the Dick Act, organized the various state militias into the present National Guard system. Because the National Guard remains under the authority of the states (unless called into federal service), it should not be confused with the reserves of the various services which serve primarily as training units for replacements to active component forces.
The Army National Guard is part of the United States Army, comprising approximately one half of its available combat forces and approximately one third of its support organisation. The Air National Guard is part of the United States Air Force. Both are maintained through the National Guard Bureau, whose Chief sits on the Joint Chiefs of Staff.
The National Guard equips and outfits its personnel in the same manner as the United States Armed Forces. The same ranks and insignia are used and National Guardsmen are eligible to receive all United States military awards. The National Guard also bestows a number of state awards for local services rendered in a service member's home state.
It is perhaps best known for its slogan used in commercials: "One weekend a month, two weeks a year". This indicated the amount of time an individual would need to spend actively in the Guard to be a Guardsman with benefits and such. It was dropped during the Iraq War after it became clear that Guardsmen were now serving considerably more time in service.
Prior to the attacks against the United States on September 11th, 2001, the National Guards policy regarding deployment was that Guardsmen would be required to serve no more than six months over seas at any time. Due to strains placed on active duty units following the attacks, the possible deployment time was increased to 18 months. Additional strains placed on military units as a result of the invasion of Iraq further increased the amount of time a Guardsmen could be deployed to 24 months.
National Guard units can be mobilized at any time by presidential order to supplement regular armed forces, and upon declaration of a state of emergency by the governor of the state in which they serve.
Unlike Army Reserve members, National Guard members cannot be mobilized individually (except through voluntary transfers), but only as part of their respective units.
Throughout the 19th century the regular Army was small, and the militia provided the majority of the troops during the Mexican War, the start of the American Civil War, and the Spanish-American War. In 1903, part of the militia was federalized and renamed the National Guard and organized as a Reserve force for the Army. In World War I, the National Guard made up 40 percent of the U.S. combat divisions in France. In World War II the National Guard made up 19 divisions. One hundred forty thousand guardsmen were mobilized during the Korean War and over 63,000 for Operation Desert Storm. They have also participated in the US peacekeeping forces in Somalia, Haiti, Saudi Arabia, Kuwait, Bosnia, and Kosovo as well as for natural disasters, strikes, riots and security for the Olympics when they have been in the states.
The National Guard is not subject to the Posse Comitatus Act and can engage in law enforcement activities even when federalized.
Following World War II, the National Guard aviation units became the Air National Guard. There is no Naval National Guard due to the constitutional provision against states having ships of war in time of peace, though both New York and Maryland have incorporated Naval Militia units.
The Air National Guard has more than 106,000 personnel and the Army National Guard (ARNG) around 350,000 personnel (2001).