Army" was organized to fight the conflict, replacing the concept of U.S. Volunteers. It was demobilized at the end of World War I, and was replaced by the Regular Army, the Organized Reserve Corps and the state militias. In the 1920s and 1930s, the "career" soldiers were known as the "Regular Army" with the "Enlisted Reserve Corps" and "Officer Reserve Corps" augmented to fill vacancies when needed. In 1941, the "Army of the United States" was founded to fight World War II. The Regular Army, Army of the United States, the National Guard and Officer/Enlisted Reserve Corps (ORC and ERC) existed simultaneously. After World War II, the ORC and ERC were combined into the United States Army Reserve. The Army of the United States was re-established for the Korean War and Vietnam War and was demobilized upon the suspension of the draft. Currently, the Army is divided into the Regular Army, the Army Reserve and the Army National Guard. Some states further maintain state defense forces, as a type of reserve to the National Guard, while all states maintain regulations for state militias. State militias are both "organized", meaning that they are armed forces usually part of the state defense forces, or "unorganized" simply meaning that all able-bodied males may be eligible to be called into military service. The U.S. Army is also divided into several branches and functional areas. Branches include officers, warrant officers, and enlisted Soldiers while functional areas consist of officers who are reclassified from their former branch into a functional area. However, officers continue to wear the branch insignia of their former branch in most cases, as functional areas do not generally have discrete insignia. Some branches, such as Special Forces, operate similarly to functional areas in that individuals may not join their ranks until having served in another Army branch. Careers in the Army can extend into cross-functional areas for officer, warrant officer, enlisted, and civilian personnel. Before 1933, members of the Army National Guard were considered state militia until they were mobilized into the U.S. Army, typically on the onset of war. Since the 1933 amendment to the National Defense Act of 1916, all Army National Guard soldiers have held dual status. They serve as National Guardsmen under the authority of the governor of their state or territory and as reserve members of the U.S. Army under the authority of the president, in the