Central Office for South Vietnam

Central Office for South Vietnam (abbreviated COSVN ; Văn phòng Trung ương Cục miền Nam), officially known as the Central Executive Committee of the People's Revolutionary Party from 1962 until its dissolution in 1976, was the American term for the North Vietnamese political and military headquarters inside South Vietnam during the Vietnam War. It was envisaged as being in overall command of the communist effort in the southern half of the Republic of Vietnam (South Vietnam), which included the efforts of both People's Army of Vietnam (PAVN), the Vietcong, and the People's Revolutionary Party. Whether COSVN actually existed, and if so, where it was located at any one time, and how important it might have been, were contentious subjects, but in his memoirs the American commander in South Vietnam, General William C. Westmoreland, spoke of it as something whose existence and importance were not in doubt. All U.S. and South Vietnamese efforts to eliminate it during the conflict failed.

History
The headquarters was reportedly created in 1961 when the southern and central branches of the Lao Dong Party (the Vietnamese Communist Party) merged into the Central Directorate for the South. An advance element of the Party's Central Committee, the headquarters was chartered to direct VC guerrilla operations in South Vietnam. Major General Tran Luong came south in May 1961 to reorganize the structure of the Directorate and its subordinate regions, Military Regions 1, 2, 3, 4, 6 and 10, known collectively as the B-2 Front. In the process, he created COSVN.

In October 1963, COSVN organized the Military Affairs Party Committee (MAPC) and the Regional Military Headquarters. COSVN's first secretary, Nguyen Van Linh, served concurrently as the secretary of the MAPC, while General Tran Van Tra became commander of the Regional Military Headquarters. Senior General Nguyen Chi Thanh, a member of the northern politburo, arrived at COSVN in late 1963 or early 1964 to serve as southern regional political officer and became the dominant figure at the headquarters until his death during a visit to Hanoi in July 1967. This regional command structure reported through Thanh to the PAVN general staff in Hanoi. When Pham Hung replaced Thanh as the politburo's representative, he also became the first secretary of both COSVN and the MAPC.

Reputed locations
During the early 1960s, COSVN was located South Vietnam's Tay Ninh Province, northwest of Saigon near the Cambodian border. During the period 1965-1970, the headquarters was based in and around the Cambodian Mimot plantation, in what was called the “Fishhook” area on the Vietnamese/Cambodian border north of Tay Ninh and west of Loc Ninh. During the Cambodian Campaign of 1970, COSVN moved westward to the area around Kratie.

This was confirmed by first person testimony provided to staff from the Cambodia-based media production group Camerado in 2008, during research for the motion picture 'Freedom Deal', which dramatizes the 1970 Cambodian Incursion from the point of view of the Cambodian people. A Cambodian community in the vicinity of Phnom Sambok, North of Kratie town, confirmed the location of staging areas for "large numbers of North Vietnamese vehicles and numerous structures" in the nearby forest.

A Time magazine in 1970 reported that rather than being a jungle Pentagon as often conceived, "COSVN is actually a staff of some 2,400 people who are widely dispersed and highly mobile", travelling between various bunkers and meeting places by bicycle and motorbike.

Subdivisions
It was believed by U.S. intelligence that COSVN had several subdivisions, each of which dealt with the political, logistical, and military aspects of the struggle in South Vietnam. For tactical reasons U.S. Radio Research units were primarily concerned with the military divisions, which were known as “MAS-COSVN” (Military Affairs Section) and “MIS-COSVN” (Military Intelligence Section). The political and logistical sub-divisions were left to the Radio Research Field Station at Phu Bai. These two sub-divisions usually occupied a location removed from, but generally near, the headquarters itself, as determined by ARDF or airborne radio direction finding.

Operations to destroy COSVN
One of the central frustrations of the U.S. military during the conflict was the Democratic Republic of Vietnam's (North Vietnam) use of Laos and Cambodia as logistical conduits and base areas. During the administration of President Lyndon B. Johnson, the U.S. military was generally not allowed by its civilian commanders to widen the war by attacking the supply routes and sanctuaries in both countries due to their ostensible neutrality. An attempt was made to capture or destroy the headquarters during Operation Junction City, a massive search and destroy operation launched in the border region in February and March 1967.

Hampering bombing runs against rebel bases like COSVN was the assistance provided by Soviet ships in the Pacific. Soviet ships in the South China Sea gave vital early warnings to NLF forces in South Vietnam. The Soviet intelligence ships detected American B-52 bombers flying from Okinawa and Guam, and relayed their airspeed and direction to COSVN headquarters. COSVN used this data to determine probable targets, and directed assets along the flight path to move "perpendicularly to the attack trajectory." While the bombing runs still caused extensive damage, the early warnings from 1968-1970 prevented them from killing a single military or civilian leader in the headquarters complexes.

Later, President Richard M. Nixon authorized border reconnaissance attacks, first in 1969 in the form of the covert bombing campaign known as Operation Menu, wherein the suspected site of COSVN in Cambodia was repeatedly and heavily bombed. In the spring of 1970, an overt ground incursion took place - first an ARVN attack and then a joint ARVN-American attack that would later be called the Cambodian Campaign.

On 18 March, the Cambodian National Assembly officially deposed the Cambodian leader Sihanouk and named Lon Nol as provisional head of state. The North Vietnamese response to the coup was swift. Even before Lon Nol's March 12 ultimatum for PAVN and NFL forces to leave Cambodia, they had begun expanding their logistical system (the Ho Chi Minh Trail) from southeastern Laos into northeastern Cambodia. After Sihanouk's overthrow and Lon Nol's anti-Vietnamese movements, PAVN launched an offensive (Campaign X) against the Cambodian army. They quickly seized large portions of the eastern and northeastern parts of the country, isolating and besieging or overrunning a number of Cambodian cities, including Kampong Cham. Fearing a joint ARVN-Cambodian attack after the coup, the COSVN was evacuated to the newly Vietnamese controlled Kratie provinces of Cambodia on March 19, 1970.

As the PRG and NLF headquarters prepared to follow the COSVN into Cambodia on March 30, they were surrounded in their bunkers by South Vietnamese forces flown in by helicopter. Surrounded, they awaited till nightfall and then with security provided by the 7th they broke out of the encirclement and fled north to unite with the COSVN in the Cambodian Kratie province. Trương Như Tạng, then Minister of Justice in the PRG, recounts the march to the northern bases as day after day of forced marches in the rain. Just before the column crossed route 7 heading north, they received word that on April 3 the 9th Division had fought and won in a battle near the city of Krek, Cambodia against ARVN forces. Years later, Trương would recall that during the escape of the Provisional Revolutionary Government just how "close [South Vietnamese] were to annihilating or capturing the core of the Southern resistance - elite units of our frontline fighters along with the civilian and much of the military leadership.

A month later, at the end of April, the Americans and ARVN tried again. The initial ARVN attack of the Cambodian Campaign was launched by Army of the Republic of Vietnam (ARVN) and U.S. ground forces, which attempted to "clean out the sanctuaries." PAVN/NLF forces, however, had already been evacuated on March 19. COSVN and its sub-divisions had already withdrawn to the Kratie area and successfully avoided destruction. A marked reduction in radio traffic and transmitter power also made them difficult to place accurately at their new location, despite close 24-hour monitoring.

The military benefits and tragic repercussions of the bombing and invasion have been contentious subjects. Westmoreland thought that it was "unfortunate" that Nixon had announced the capture of COSVN as one of the primary objectives of the Cambodian operations. This left Nixon open to critics, who were already scornful of Nixon, to mock the notion of the president obsessing over COSVN as if it were a "holy grail". Kissinger was quoted as saying that the Cambodian invasion to destroy COSVN and other headquarters complexes bought the Americans and South Vietnamese a year. Members of the COSVN generally agree, but view the long-term political advantage gained as being worth the cost of the evacuation.