National Command Authority (NCA) is a term that was used by the Department of Defense of the United States of America to refer to the ultimate source of lawful military orders. The NCA was first alluded to in a 1960 Department of Defense document. It included at least the president of the United States as commander-in-chief and the secretary of defense. The term has no statutory or constitutional basis and was replaced in 2002 in favor of explicitly referring to the president and/or the secretary of defense.