The Viet Cong were associated with South Vietnam, not the regular soldiers from North Vietnam. They were labeled such (as traitors) by the South Vietnamese. The North Vietnamese were generally not called Viet Cong. (On the other hand, the Viet Cong were a part of the organization of the North Vietnamese Army and “Charlie” could refer to “Communist” regardless of North or South. However, Viet Cong was typically a reference to fighters operating in the South.)