Campaign Series Vietnam | Big Ernie's Scuttlebutt

As you were, Grunts,

Did you ever suspect there was a connection between Cambodia and Kent State University?

This article discusses the Cambodian Incursion in 1970, and the US political turmoil over the Kent State University shooting.

Cambodian Political Inclination Under Prince Sihanouk

Under Prince Sihanouk, Cambodia aligned with Communist Bloc nations. He believed  that Communism was the eventual “wave of the future” for all Southeast Asia.

However, for centuries, Cambodians held intense mistrust toward Vietnamese. Against the Viet Minh invasion in 1954, Cambodians hated them more as Vietnamese than as Communists.

Cambodia emerged from the First Indochina War with good reason to fear North Vietnam. But, traditional hatred and suspicion of the Vietnamese extended as much to anti-communist South Vietnam as it did to the North.

During the early 1960s, Prince Sihanouk played a game of “diplomatic ping-pong” with Communist China and the United States. It was policy of manipulation, favoring first one side, then the other, which helped keep opponents off guard.

Sihanouk initially accepted aid from the US. The Communist Chinese were also eager to befriend Cambodia, and invited him to a state visit to China, hosted by Mao Tse-tung and Chou En-lai.

Prince Sihanouk gradually became unhappy with US aid, and with what he considered American attempts to dictate to him. In 1963, Cambodia terminated all US assistance.

Convinced that South Vietnam could not win, even with powerful American aid, the Prince felt that permitting North Vietnamese supplies and munitions to funnel through Cambodia, he was protecting his country from possible Chinese fury when the Communists took over all of Vietnam.

1965 Meeting in Peking: Mao Zedong, Peng Zhen, Norodom Sihanouk, and Liu Shaoqi

1965 Meeting in Peking: Mao Zedong, Peng Zhen, Norodom Sihanouk, and Liu Shaoqi

North Vietnamese in Cambodia

The NVA maintained sanctuaries along the Cambodian border with South Vietnam. They built base areas (BA) from the tri-border area of Cambodia-Laos-South-Vietnam southward to where the border meets the Gulf of Siam. These BAs were particularly placed opposite the CTZ III and IV, with close proximity to Saigon. Of 14 BAs located on the Cambodian border, 8 were contiguous to III CTZ alone.

Prior to 1966, North Vietnam sent arms, ammunition, and supplies to coastal depots in CTZ III and IV by sea. But, a US Naval blockade, Operation “Market Time,” closed these direct sea routes.

And then, Sihanoukville, a Cambodian seaport on the Gulf of Siam, began receiving arms shipments from North Vietnam. These were delivered over land to sanctuaries, and BAs straddling the border. This had tacit approval of the Cambodian government.

Cambodia also provided secure infiltration routes from North Vietnam via the Ho Chi Minh Trail. Cambodian territory provided a safe extension of infiltration trails to CTZ III and IV.

The Communist base areas contained NVA/VC installations, fortifications, and logistics storage. These were used for regrouping, resting personnel, and training. Political, military, or logistical headquarters were located in BAs, where they planned offensive operations.

Some of the most important BAs were 353, 707, and 354. BA 353 was located  along the northern border of Tay Ninh Province, and was a staging area for attacks along Highway 7. This BA also served as the location of COSVN HQ, and became a primary target area for Allied sweep operations. Several NVA 7th Division elements later operated from here.

BA 707 was in the Dog’s Head area on the northwestern Tay Ninh Province border. It was an operating area for the VC 272d Regiment, 9th Division.  BA 354, to the south, was also used by the VC 9th Division.

COSVN Base Areas along Cambodia-South Vietnam Border

COSVN Base Areas along Cambodia-South Vietnam Border

Cambodia’s Rift with Vietnamese Communists

NVA/VC presence in Cambodia fomented resentment. Their need for food, and resources to support them distorted the price system, and led to graft, corruption, and bureaucratic malfunctions. This increased resentment toward Prince Sihanouk.

Government officials blamed Sihanouk for Communist collaboration and poor economic policies. The military leaders found fault with Sihanouk for being inconsistent.  While the Prince condemned Communists in speeches, he forced the military to release all Viet Cong prisoners.

The “Salvation Government” of Lon Nol

Lon Nol and Sirik Matak agreed that the only way to return Cambodia to order was to limit the Chief of State’s power. When Sihanouk asked Lon Nol to form a cabinet, he replied that he would form a government only as Premier, and not merely a secretary to Sihanouk.

Nol also indicated he would not agree to form a government until Sihanouk met further conditions: principally, that Nol would have the right to choose his own ministers, and that they would report to him, not to Sihanouk. The Chief of State, however, could keep control over foreign policy. Sihanouk accepted. and the cabinet took office on 12 August 1969.

The new Premier Lon Nol and his appointed deputy, Sirik Matak issued decrees to solidify their position. All government communications and letters were to be addressed to the Premier’s office rather than to the Chief of State. Taxes were no longer paid into the Chief of State’s treasury, but into the Government’s accounts instead.

During an absence from Phnom Penh in early 1970, Lon Nol left Sirik Matak in charge. Friction between Matak and Sihanouk became intense. Sihanouk felt that Matak was unfairly limiting the Chief of State’s influence over domestic politics, and that he was intruding on his foreign policy prerogatives. Matak accused Sihanouk of reneging on his mandate to allow the Salvation Government to solve domestic problems.

After three unsuccessful coup attempts to cause the Salvation Government collapse, Sihanouk departed for Europe, USSR, and China on 6 January 1970. Sihanouk’s absence left the government and the country totally in the hands of Lon Nol and Sirik Matak.

Anti-Communist Measures Begin

Lon Nol and Matak began taking measures against the NVA/VC. They closed the Hak Ly Trucking Company. This cut off the supply route from the Gulf of Siam port of Kompong Sam (Sihanoukville) to Communist base areas along the South Vietnam border.

They also took military action to drive Communists back across the border into South Vietnam. In December 1969, Sirik Matak issued orders to Cambodian Army units ( Royal Khmer Armed Force, or FARK,) to attack NVA/VC troops in Cambodia, especially in Prey Veng Province.

Using the bombing of Dak Dam by US aircraft as a pretext, Matak requested the NVA/VC to move out of Cambodia. He ordered destruction of their installations in Svay Rieng Province, and directed that food supplies to the Communists be discontinued. In February 1970 FARK units moved into the BA 702 Tri-border area.

Public Demonstrations Begin

The Cambodian people’s hostile feelings intensified over failures to remove the Communist forces had finally reached a peak. Demonstrations flared up in early March, particularly in Svay Rieng Province, but also in the capital Phnom Penh. Finally, protesters ransacked the North Vietnamese Embassy.

Vietnamese Communist Reaction

The North Vietnamese resisted orders to withdraw. COSVN directed its forces to maintain vigilance, avoid provocations, remain calm, and try to win over the Cambodian people and local officials.

In late March, particularly after the Lon Nol coup, COSVN decided they would have to fight the Cambodians. A NVA/VC force of approximately 2000 troops attacked and occupied a Cambodian military post near the northwestern Tay Ninh Province border on 29 March.

Joint Cambodian – South Vietnamese Operations

Cambodian and South Vietnamese border officials planned their first joint operation. American advisors participated, but were unaware that the operation would not be limited to· boundaries of South Vietnam. The planning agreed upon, two FARK battalions served as a blocking force as three ARVN Ranger battalions pushed at least two miles into Cambodian territory.

Despite the Cambodian-South Vietnamese moves against them, NVA/VC forces in Cambodia were not in serious danger. They enjoyed almost unrestricted movement in southern Kandal and Prey Veng Military sub-divisions, and overran several Cambodian defense posts.

 Lon Nol Appeals for Help

The survival of the Salvation Government depended on foreign assistance and leadership to organize military resistance. Chaotic economic problems emphasized this need. Lon Nol to appealed for arms from any country that would provide them. And, he wrote a letter to President Nixon on 15 April for help.

US Response

After careful appraisal of Cambodia’s aid request, on 22 April the White House approved the supply of several thousand rifles to Cambodia. Meanwhile, Washington and Saigon agreed that ARVN would mount limited attacks on suspected NVA/VC sanctuaries in Cambodia.

While ARVN troops moved toward the Cambodian border, US forces maneuvered into blocking  positions for ARVN troops. The buildup of Allied forces along the Dog’s Head, Parrot’s Beak, and Fishhook areas of the border increased rapidly, but still no American ground forces entered Cambodia.

But, by the end of April, communist forces overran the entire eastern portion of Cambodia, and disrupted or threatened several provincial capitals, and posed a threat to Phnom Penh. Stronger measures were needed immediately to resolve the situation.

On 29 April, the White House announced that it was providing advisors, tactical air support, and supplies to ARVN forces in Cambodian operations. Then, on 30 April, President Nixon announced on television the incursion of US troops into Cambodia for the first time. As he spoke, American combat troops moved across the border into the Fishhook area of Cambodia. ARVN forces were attacking in several other areas, including the Parrot’s Beak.

US Intelligence

A considerable amount of SIGINT was available to MACV. In fact, they had a pretty good idea on the location of COSVN most of the time. The Army units involved were radio research groups, battalions, and companies. These units had radio recievers and transmitters, cryptologists, and language translators. The main group reporting to MACV was the 509th Radio Research Group in Saigon.

In particular, the 175th Radio Research Company was a nerve center for SIGINT support. In the early days of this operation were crucial. COSVN location and communications required particular emphasis. An OPSCOMM conversation on 1 May between the 175th RRC and NRV discussed 12 high interest targets.

Operation Rock Crusher

Attacks on the Parrot’s Beak area involved 12 ARVN battalions of approximately 8700 troops. These were two armored cavalry squadrons from III Corps, and two from the 25th Division and 5th Infantry Divisions, an infantry regiment from the 25th Infantry Division, and three Ranger battalions with an attached ARVN Armored Cavalry Regiment. They crossed into the Parrot’s Beak region of Svay Rieng Province. The operation commander was Lieutenant General Do Cao Tri.

On 1 May an even larger operation was underway as B-52s dropped 774 tons of bombs along the southern edge of Fishhook. This was followed by massed artillery fire air strikes by tactical fighter-bombers. The US 1st Air Cavalry Division, the 11th Armored Cavalry Regiment, the 1st ARVN Armoured Cavalry Regiment, and the 3rd ARVN Airborne Brigade entered Kampong Cham Province of Cambodia.

The operation failed to capture COSVN, one of its primary objectives. The NVA evaded US and ARVN forces, and mostly withdrew into Laos. However large NVA supply caches were found and destroyed.

The PAVN  response was to avoid contact with allied forces and, if possible, to fall back westward and regroup. They were well aware of the planned attack, and many COSVN and B-3 Front military units were already far to the northwest conducting operations against the Cambodians when the offensive began.

This actually started the largest expansion of the Ho Chi Minh trail in the entire conflict. As a response to the loss of their Cambodian supply route, NVA forces seized the Laotian towns of Attopeu and Saravane during 1970.

The aftermath of the incursion for the US and ARVN was to destroy large supply depots.  Units entered what came to be known as “The City”, southwest of Snoul. The NVA complex contained over 400 thatched huts, storage sheds, and bunkers, each of which was packed with food, weapons, and ammunition. There were truck repair facilities, hospitals, a lumber yard, 18 mess halls, a pig farm, and even a swimming pool.

Other 1st Cavalry Division elements discovered a larger base,  nicknamed “Rock Island East” after the Rock Island Arsenal in Illinois. The area contained more than 6.5 million rounds of anti-aircraft ammunition, 500000 rifle rounds, thousands of rockets, and large quantities of communications equipment.

Unfortunately for the MACV war effort, political blowback in the United States was swift and intense.

Kent State Shooting

Protests against the Vietnam War had been ongoing since the 1968 Tet Offensive, but the Cambodian Incursion gave new impetus to the protest movement.

President Nixon had campaigned on ending the Vietnam War. But, with the Cambodian involvement, it seemed to many that he had broken his promise. This also gave many left-wing radical activist groups such as the Students for a Democratic Society, (SDS) and the Weathermen a pretense to agitate.

At Kent State University (Kent, Ohio,) these protests began on 1 May, the day after Nixon’s address. That day, hundreds of students gathered on the Commons, an open space at the center of campus that had been the site of large demonstrations.  Several speakers spoke out against the war in general, and President Nixon specifically. Some of these were from outside radical groups, and not Kent State students.

That night, violent clashes occurred between activists and police. Bottles were thrown at cars and protesters stopped traffic and lit bonfires in the streets.

Reinforcements were called in from neighboring communities, and Kent Mayor Leroy Satrom declared an emergency, and ordered all bars closed. Satrom also contacted Ohio Governor James Rhodes, seeking assistance.

The Ohio National Guard arrived at the Kent State campus on the night of May 2nd, however, protesters had already set fire to the school’s ROTC building, and scores were watching and cheering as it burned. Some protesters also reportedly clashed with firefighters attempting to put out the blaze, and Guardsmen were asked to intervene. Clashes between the Guard and the protesters continued well into the night, and dozens of arrests were made.

The next day, Sunday on 3 May, the campus was relatively quiet, despite 1000 Guardsmen at the school. However, a major protest was scheduled for 4 May.

At noon 4 May on the Commons, protesters gathered. University officials attempted to diffuse the situation by prohibiting the event. Still, crowds began to gather at about 1100 that morning, and an estimated 3000 protesters and spectators were there by the scheduled start time.

Stationed at the smoking ruins of the ROTC building were roughly 100 Guardsmen carrying M-1 Garand rifles. Although the protests were initially peaceful, General Robert Canterbury ordered the protesters to disperse, with the announcement being made by a Kent State police officer riding in a military jeep across the Commons and using a bullhorn. Protesters refused to disperse, and began shouting and throwing rocks at the Guardsmen.

General Canterbury ordered his men to lock and load their weapons, and to fire tear gas into the crowd. The Guardsmen then marched across the Commons, forcing protesters to move up a nearby hill called Blanket Hill, and then down the other side of the hill toward a football practice field.

As the football field was enclosed with fencing, the Guardsmen were caught amongst the angry mob, and were the targets of shouting and thrown rocks yet again. The Guardsmen soon retreated back up Blanket Hill.

As the Guardsmen moved to the top of Blanke Hill, shots were fired, not from the Guards, but from a  38 revolver carried by photographer, Terry Norman. He had apparently fired into the air and ground.

An angry mob surrounded Norman, and he sought protection from the Guardsmen.

Kent State Campus

A command was given, “prepare to fire.” But there was a pause. And then, more than a minute later, frightened and undisciplined Guardsmen began firing. 29 out of 77 guardsmen fired 67 times for 13 seconds. This killed four students, Allison Krause, Jeffrey Miller, Sandra Scheuer, William Schroeder, and wounded nine others.

Following the shooting, the university was immediately closed, and the campus remained shut down for six weeks. Numerous investigatory commissions and court trials followed, during which members of the Ohio National Guard testified that they felt the need to discharge their weapons because they feared for their lives.

In a civil suit filed by injured Kent State students, a settlement was reached in 1979 in which the Ohio National Guard agreed to pay a total of $675,000.

The impact of this incident on the American psyche was devastating. It ended any hope for public support of the Vietnam War, and greatly weakened President Nixon’s credibility.

Mary Ann Vecchio kneeling over Jeffrey Miller minutes after his shooting

Mary Ann Vecchio kneeling over Jeffrey Miller minutes after his shooting


“Focus on Cambodia, Parts 1 and 2”, NSA Cryptologic History Series, January 1974

“Cambodian Campaign”, Wikipedia

“Kent State Shooting”, History Channel

“Kent State shootings”, Wikipedia

“Kent State: The Rest of the Story”, Roger Canfield

Campaign Series Vietnam | Big Ernie's Scuttlebutt

Maj Gen Ernest Cheatham, USMC


Big Ernie’s Scuttlebutt is the latest series of articles by David Galster that provides an overview of the events in Vietnam from 1969 onward. The articles provide some interesting background information for the upcoming release of Campaign Series: Vietnam.