The Army National Guard consists of the part of the organized militia of the several States and Territories, Puerto Rico, and the District of Columbia, active and inactive, that (A) is an air force; (B) is trained, and has its officers appointed, by the States according to the discipline prescribed by Congress*; (C) is organized, armed, and equipped wholly or partly at Federal expense; and (D) is federally recognized.
* - U.S. Constitution, article I, section 8, clause sixteen
See: U.S. Code title 32 § 101 | 
