Corps / Military Regions

What made the South Vietnamese armed forces so different from the usual military aggregation was the fact that the military is responsible not only for the defense of the nation, but for much of its civil administration as well. The regular divisions of the ARVN were striking forces coming under the direction of the general officer commanding each of the four Corps Tactical Zones into which South Vietnam was divided. But in addition to his military functions, each corps commander is responsible for civil administration within his CTZ.

The Regional Forces companies came under the tactical command of the chief of each of the 44 provinces, who was usually an ARVN lieutenant colonel or colonel, yet that province chief also is responsible for civil administration within his province. The Popular Forces, usually in static defense near each platoon's home village, came under the direct supervision of the village chief, a civilian elected to head the committee administering the routine civil life of the village. But his military commissioner was a PF officer, and in practice both RF and PF units were deployed and led in local operations by the district chief. District chiefs were ARVN captains or occasionally majors, and they were responsible through channels for RF/PF actions and civil activities within their 243 districts. While neither province chiefs nor district chiefs deployed the regular ARVN divisions within their jurisdictions -- company-grade and field-grade officers do not make troop dispositions for a general officer's command -- they did coordinate their RF/PF operations with the local ARVN commander, often can "borrow" ARVN elements for their offensive requirements, and occasionally take part in massive cordon operations involving all regular, territorial and paramilitary forces in the area. It was doubtful a civilian province chief could achieve such smooth-working arrangements.

Within each CTZ there was a dual command structure. The principal military channel went from corps commander to division and regiment. A second channel went from corps commander through the province chiefs to district chiefs. Each channel has its own prerogatives and forces. By the late 1960s there was a trend away from concentration of all civil power in corps headquarters, with province chiefs being appointed by Saigon rather than by the corps commanders and with central government ministries communicating directly with province chiefs. Most villages and hamlets elected their own chiefs and administrative bodies, so province and district chiefs had advisory, coordinating and occasionally veto functions in the villages rather than administrative tasks. But some 291 military officers from general to captain stationed at corps, province and district headquarters still had heavy responsibility for the day-to-day activities and the general well-being of their jurisdictions.

This dual civil-military responsibility evolved from the necessity of martial law in a country at war, and continued even after popular elections were held under the Second Republic because it was found that in a society so long at war it was inevitable that the best manpower resources, the best leaders and administrators, were in uniform. Cabinet ministers, city mayors and a number of other government officials have had to be recruited from the ranks of the military. One of the advantages is that officers experienced in the dual system develop a comprehensive grasp of the war in its total military, political and psychological compass.

The Republic of Viet Nam's system of Military Regions (MRs) which was instituted in 1970 was the most recent development in the evolution of military regions which began in 1952 under the French. At first, the limits of the military regions were defined in terms of the boundaries of the already existing units of civil administration. However, before long units of civil administration (provinces and districts) were being defined as being part of the territory of the military regions, both in Government documents and in everyday speech. Thus the division of the Republic of Viet Nam into military region is of considerable importance in both the military and civil spheres

The history of the military regions can be divided into three phases:

  1. 1952 -- 1961: The old system of military regions organized by the French;
  2. 1961 -- 1970: The system of Corps Tactical Zones (and subsidiary Division Tactical Areas and. Special Tactical Zones). (The 44th Special Tactical Zone along the Cambodian border in MR 4 was not phased out until late 1973.) The corps tactical zones -- termed simply tactical zones (TZs) (vung chien thuat) in Vietnamese -- were an outgrowth of the formation of military corps: I and II Corps in 1957, III Corps in 1959, and, later, IV Corps in 1963;
  3. 1970 to 1975: The final system of military regions.

Decree 614b-TT/SL of July 1, 1970 re-established a system of military regions and abolished the corps tactical zones (vung chien thuat) and tactical areas. However, each of the military regions (MRs) is the responsibility of a corps; thus

  1. I Corps is in charge of MR-1,
  2. II Corps is in charge of MR-2,
  3. III Corps is in charge of MR-3,
  4. IV Corps is in charge of MR-4.
The corps headquarters is at the same time the headquarters of the military region; the corps commander in also the military region commander. Each corps/military region reports directly to the Joint General Staff of RVNAF. Each corps/military region is responsible for military operations in its area, territorial security, pacification (termed reconstruction and development since 1973) and various other matters. To this point, a position called the "Government Delegate" had existed in each Corps, theoretically equal in authority to that of the Corps Commander; the Delegate exercised the civilian authority of the Government. In practice, the Delegate's position was in each case cumulated by the Corps Commander, who was assisted in discharging this function by a senior civil servant who bore the title "Assistant to the Government Delegate". Until 1968, and depending upon the personalities involved, the Assistant in some instances was a fairly important figure. Following the impact of the Tet offensive in early 1968, whatever authority the Assistants had previously exercised rapidly eroded and the position was subsequently eliminated.

South Vietnam consisted of three major geographic features. The three disparate topographical regions in the South -- highlands, coastal lowlands, and Mekong Delta -- favored the insurgent. The coastal plain, varying in width from fifteen to forty kilometers, extended along most of the 1,400 kilometers of the coast. This plain abuts the second feature - the southeastern edge of the Annamite Mountain Chain, known in South Vietnam as the Central Highlands, which run from the northern border along the old Demilitarized Zone south to within eighty kilometers of Saigon. The Central Highlands are mostly steep-sloped, sharp-crested mountains varying in height from 5,000 to 8,000 feet, covered with tangled jungles and broken by many narrow passes. The southern third of the country consists almost entirely of an arable delta.

These three geographical features helped shape the four military zones of South Vietnam. The northern zone, or I Corps Zone, which ran from the Demilitarized Zone down to Kontum and Binh Dinh provinces, consisted almost entirely of high mountains and dense jungles. At several points the Annamites cut the narrow coastal plain and extend to the South China Sea. II Corps Zone ran from I Corps Zone south to the southern foothills of the Central Highlands, about one hundred kilometers north of Saigon. It consisted of a long stretch of the coastal plain, the highest portion of the Central Highlands, and the Kontum and Darlac Plateaus.

The highlands extend past the western boundary into Laos and upper Cambodia, a nationally unpoliceable territory where insurgents may build major bases and find sanctuary after a military operation across the border in Vietnam. III Corps Zone ran from II Corps Zone southwest to a line forty kilometers below the capital, Saigon. This was an intermediate geographic region, containing the southern foothills of the Central Highlands; a few large, dry plains; some thick, triple-canopy jungle along the Cambodian border; and the northern stretches of the delta formed by the Mekong River to the south.

IV Corps Zone was in the third major area is the flat and fettile Mekong Delta, where almost anything will grow and the counterinsurgent's problem is the difficulty of denying food to the enemy. This vast area was made arable and habitable by the French who drained swampland and laced the region with canals. The nearby Cambodian border and almost impenetrable swamps provide secure bases in close proximity to much of the Delta population. IV Corps Zone consisted almost entirely of this delta, which has no forests except for dense mangrove swamps at the southernmost tip and forested areas just north and southeast of Saigon. Seldom more than twenty feet above sea level, the delta is covered with rice fields separated by earthen dikes. During the rainy season the paddies are marshy, making helicopter landings and vehicular troop transport extremely difficult. Hamlets straddle the rivers and canals, and larger villages (up to 10,000 people) and cities lie at tile junctions of the waterways. Bamboo brakes and tropical trees grow around the villages and usually extend from 50 to 300 meters back on either side of the canal or hamlet.

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