The Maine Army National Guard is a component of the United States Army and the United States National Guard. Nationwide, the Army National Guard comprises approximately one half of the US Army's available combat forces and approximately one third of its support organization. National coordination of various state National Guard units are maintained through the National Guard Bureau. The Guard is administered by the adjutant general, an appointee of the governor of Maine. The Constitution of the United States specifically charges the National Guard with dual federal and state missions. Those functions range from limited actions during non-emergency situations to full scale law enforcement of martial law when local law enforcement officials can no longer maintain civil control.