Green beret
U.S. Special Forces wear the green beret as a distinction of excellence and uniqueness within the Army.
Delta Force
The origin of the term operator in American special operations comes from the U.S. Army Special Forces (aka the Green Berets). The Army Special Forces was established in 1952, ten years before the Navy SEALs and 25 years before DELTA. Every other modern U.S. special operations unit in the Army, Navy, Air Force and Marines was established after 1977. In "Veritas: Journal of Army Special Operations History", Charles H. Briscoe states that the Army "Special Forces did not misappropriate the appellation. Unbeknownst to most members of the Army Special Operations Force (ARSOF) community, that moniker was adopted by the Special Forces in the mid-1950s." He goes on to state that all qualified enlisted and officers in Special Forces had to "voluntary subscribe to the provisions of the 'Code of the Special Forces Operator' and pledge themselves to its tenets by witnessed signature." This pre-dates every other special operations unit that currently uses the term/title operator.