There are three main components of the US Army. They are the Active Army, the Army Reserves and the Army National Guard. As part of the US Army, the Army National Guard plays a crucial role.
Traditionally, Guardsmen are civilians who complete their service on a part time basis, usually one weekend per month and two weeks at some other time of the year. These Guardsmen form state guard forces who may be called to duty at any time to mobilize and assist where needed.
Often, state emergencies such as natural disasters like hurricanes, tornadoes, flood and fire, as well as civil disturbances rely on National Guardsmen to provide the security and protection, as well as rescue efforts needed in such events. Additionally, the President has the power to activate the National Guard to assist with federal needs such as combating terrorism abroad, or providing help in famine and war ravaged areas of the world.