active duty to supplement regular armed forces during times of war or national emergency declared by Congress, the President or the Secretary of Defense. They can also be activated for service in their respective states upon declaration of a state of emergency by the governor of the state or territory where they serve, or in the case of Washington, D.C., by the Commanding General. Unlike U.S. Army Reserve members, National Guard members cannot be mobilized individually, except through voluntary transfers and Temporary Duty Assignments (TDY). The types of activation are as follows: National Guard active duty character The term "activated" simply means that a unit or individual of the reserve components has been placed on orders. The purpose and authority for that activation determine limitations and duration of the activation. The Army and Air National Guard may be activated in a number of ways as prescribed by public law. Broadly, under federal law, there are two titles in the United States Code under which units and troops may be activated: as federal soldiers or airmen under Title 10 ("Armed Forces") and as state soldiers or airmen performing a federally-funded mission under Title 32 ("National Guard"). Outside federal activation, the Army and Air National Guard may be activated under state law. This is known as state active duty (SAD). State and territory duty When National Guard units are not under federal control, the governor is the commander-in-chief of the units of his or her respective state or territory (such as Puerto Rico, Guam and the Virgin Islands). The President of the United States commands the District of Columbia National Guard, though this command is routinely delegated to the Commanding General of the DC National Guard. States are free to employ their National Guard forces under state control for state purposes and at state expense as provided in the state's constitution and statutes. In doing so, governors, as commanders-in-chief, can directly access and utilize the Guard's federally assigned aircraft, vehicles and other equipment so long as the federal government is reimbursed for the use of fungible equipment and supplies such as fuel, food stocks, etc. This is the authority under which governors activate and deploy National Guard forces in response to natural disasters. It is also the authority under which governors deploy National Guard forces in response to man-made emergencies such as riots and civil unrest, or terrorist attacks. The Governor can