Republic of Vietnam
Formally named the Republic of Vietnam (RVN) and commonly called South Vietnam (SVN), this is the political entity created by the Geneva Accords of 1954 that partitioned former French Indochina, and whose existence ended with the forcible occupation of the South by Communist forces of the North.
While the dominant ideology of the North (i.e., the Democratic Republic of Vietnam (DRV) or North Vietnam (NVN), the Government of Vietnam (GVN) can be characterized as anticommunist, but, beyond that generalization, it is hard to have one consistent view of its political system. At various times, its wasbriefly led by a figurehead "Emperor", Bao Dai; led by what can most gently called Confucianist authoritarians such as Ngo Dinh Diem, giving preference to a Catholic minority; and by a series of military governments. Widespread democratic institutions never evolved, and there remained, regardless of the leadership, an endemic problem with government corruption.
Military
The main ground force of the RVN was commonly called the Army of the Republic of Vietnam. There were smaller separate Air Force and Navy branches. Airborne, Ranger, and Marine units served as strategic reserves and "fire brigades", without clear identities as services.
To varying extents, some of the leadership came from roles in the French military, or from groups that resisted the World War II Japanese invasion.
Vietnamese Special Forces did have a conceptual politicomilitary and village-oriented function similar to United States Army Special Forces, but, especially under Diem, they acted as a political police rather than as a nation-building organization. Even so, there were competent individuals that improved specific situations.