32 U.S.C. § 102 — General policy

This section is not split into lettered parts. It sets out the long-standing military policy of the United States. The Army National Guard and the Air National Guard are treated as an essential, integral part of the country's first line of defense. The law says their strength and organization must always be kept up and guaranteed. If Congress decides that the regular Army and Air Force do not have enough units and organizations to meet national security needs, then the National Guard steps in. The Army National Guard of the United States and the Air National Guard of the United States — or as much of them as is needed — must be called to active federal duty. Other reserve units can be added too, as needed, to build a balanced force. Once called up, these units stay on active duty for as long as they are needed.