The term militia in the United States has been defined and modified by Congress several times throughout U.S. history. As a result, the meaning of "the militia" is complex and has transformed over time. It has historically been used to describe all able-bodied men who are not members of the Army or Navy (Uniformed Services). From the U.S. Constitution, Article II (The Executive branch), Sec. 2, Clause 1: "The President shall be the Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States when called into the actual service of the United States."