Review and Analysis: United States Secret Wars in Cambodia: Long-Term Impacts and Consequences ()
1. Introduction
1.1. America’s 1959 Secret War on Ho Chi Minh Trail in Cambodia and Laos
Once called Annamite Range Trail, the Ho Chi Minh Trail was a logistical network of trails and roads from North Vietnam to South Vietnam through the Kingdoms of Cambodia and Laos (Figure 1). During the Vietnam War, the trail system provided support, in the form of labor and supplies to the PAVN and Viet Cong guerrillas [1] . Construction for the network began after the North Vietnamese invasion of Laos in July 1959.
The trail was named after the North Vietnamese President Ho Chi Minh. The origin of the name is presumed to have come from the First Indochina War. There was a Viet Minh, an organization formed in China by Ho Chi Minh in 1941, maritime logistics supply line called the “Route of Ho Chi Minh” [1] . Agency France Presse (AFP) announced that a north–south trail had opened, and they named the corridor La Piste de Hồ Chí Minh, the “Hồ Chí Minh Trail”. The trail through Laos (Figure 2) and Cambodia (Figure 3) was called the Truong Son Strategic Supply Route by the communists which was the Vietnamese name for the Annamite Range Mountains in central Vietnam [2] . They further identified the trail as either East Trường Sơn (Vietnam) or West Trường Sơn (Laos) [3] . According to the U.S. National Security Agency’s official history of the war, the trail system was considered “one of the great achievements of military engineering of the 20th century” [4] . The trail was able to effectively supply troops fighting in South Vietnam during the time of the single most intense air interdiction campaign in world history (Figure 4). Parts of what became the trail had existed for centuries as trade footpaths. The area through which the trail system operated was among the most difficult to traverse in Southeast Asia. The trail ran through a sparsely populated region of rugged mountains 500 - 2400 m in elevation, and dense tropical rainforests and triple-canopy jungle.
1.2. Unintended Consequences of the 1969 United States Secret War in Cambodia
In the book, Bombs over Cambodia, historians Taylor Owen and Ben Kiernan [5] state that, “based on their analysis of the declassified documents, 2,756,941 tons of ordnance was dropped during Operation Menu, more than the US dropped on Japan during World War II”. The authors also say, “That US planes flew 230,516 sorties over 113,716 sites [5] . Estimates of casualties vary widely as well, but it is believed that somewhere between 100,000 and 600,000 civilians
![]()
Figure 1. The Ho Chi Minh Trail through the mountains and jungles of Vietnam, Laos and Cambodia was a system of trails and paths controlled by the Democratic Republic of Vietnam (1959-1975) used for transporting food, military equipment and North Vietnamese Army soldiers into southern Vietnam during the Vietnam War. Map by Cruz Dragosavac. Reprinted with permission from Editor of Open Journal of Soil Science.
![]()
Figure 2. Picture of Ho Chi Minh Trail. Reprinted with permission from Editor of Open Journal of Soil Science.
![]()
Figure 3. PAVN troops fording a stream with crude underwater bridge from North Vietnam on the Ho Chi Minh trail in the 1960s. Reprinted with permission from Editor of Open Journal of Soil Science.
died in the bombing and two million became homeless” [5] . Other sources say that hundreds of thousands more Cambodians died from the effects of illness, displacement, or starvation as a direct result of the spraying and bombings. The carpet-bombing of Cambodia (Figure 4) lasted until August 1973. The countryside was devastated and resulted in chaos and upheaval it unleashed played an important part in the installation of the genocidal Khmer Rouge regime led by Pol Pot. The U.S. bombing campaign increased the Cambodian civilian death toll and resulted in the insurgency (Khmer Rouge) being able to recruit support from the local civilians. The strengthened Khmer Rouge, led by Pol Pot, won the Cambodian Civil War and overthrew the Khmer Republic in 1975.
The Khmer Rouge was responsible for the deaths of up to two million Cambodians through forced labor, executions, and starvation [6] . According to intelligence gathered by the CIA, U.S. bombing by the United States Air Force increased the popularity of the Khmer Rouge and gave the Khmer Rouge a major propaganda weapon which they used to achieve a 1975 victory [7] .
At the urging of National Security Adviser Henry Kissinger, President Nixon reportedly authorized the bombing of Cambodia [5] . They both believed it was important to stop the flow of communist troops and supplies into Vietnam in order to end the war as soon as possible.
The North Vietnamese Army proved to be far more resilient than anticipated. The U.S. secret war in Cambodia did help end the Vietnam War. However, in the spring of 1970, leaked news of the bombing sparked intensified anti-war US protests. On May 4th, students in the U.S., protesting the bombing of Cambodia, clashed with Ohio National Guardsmen on the Kent State University campus (Figure 5). After Guardsmen fired into the crowd, killing four students, the anti-war sentiment in the U.S. became unstoppable. Faced with that reality, President Nixon essentially turned over South Vietnam to the North Vietnamese when he signed the Paris Peace Accords in January 1973 [5] [6] [7] .
The primary objectives of this study are to determine the political impacts and consequences of: 1) the 1959 United States secret war on the Ho Chi Minh Trail in Cambodia and 2) the 1969 President Nixon’s decision to secretly use defoliants
![]()
Figure 4. B-52s bomber dropping bombs. Photo Credit: United States Air Force.
![]()
Figure 5. Picture taken at Kent State during a Student Demonstration by John Paul Filo.
and to bomb Cambodia in order to destroy the hidden PAVN bases. The decisions to spray and bomb would have long-lasting effects on Cambodia’s political, social, and economic stability.
2. Geology and Soils
Cambodia, is entirely within the tropics and has a 443 km coastline along Gulf of Thailand. The Cambodian soils can be categorized into three distinctly different groupings: 1) regions that presently receive annual alluvial sediments including the Tonle Sap bottomlands, 2) regions that retained their original parent material, such as the Central Annamite and Cardamom mountains, 3) regions that are covered by ancient colluvial or alluvial plains [8] . The central plain includes Tonle Sap Lake and River and the upstream reaches of the Mekong River delta [9] . The margins of the low-lying central plains are transitional plains consisting of Old Alluvium (Ultisol and Oxisol soils) that rise 200 m above sea level and are thinly forested. North of these plains, from east to west, is a sandstone escarpment stretching 320 km.
Cambodia’s soils are low in nutrients and sandy. The red-soil regions (Oxisols and Ultisols) grow commercial crops such as rice (Oryza sative), cotton (Gossypium herbaceum), tobacco (Niotina tobaccum), wheat (Triticum aestivum), and perennial tree crops like coconut (Cocos nucifera) and rubber (Hevea brasiliensis). The Mekong River during the annual wet season carries rich alluvial sediments that are deposited on the floodplains. These floodwaters enhanced the central plain soil fertility by providing natural irrigation for rice cultivation. Highlands are forested high mountains and plateaus which rise above the plains. The Damreh and Kravanh mountains form a highland region between Gulf of Thailand and Tonle Sap Lake [10] .
The Cambodian Mekong floodplain is a narrow low-lying area with an elevation of less than 100 m. Sediment deposits at Phnom Penh are about 30 m thick. Upstream, the Mekong River is northeast from Phnom Penh to Kampong Cham and then turns north to Kratie where bedrock falls block boat traffic on the river during the dry season [10] . Sediments deposited on Tonle Sap Lake plain (8000 to 7300 BC) contain vegetation materials and marine animals suggesting the ancient South China Sea once came this far inland. Analyses of geologic and soil cores collected near Angkor Borei, downstream of where the Mekong and Tonle Sap rivers currently confluence reveal sediments that were deposited in the presence of tides, mangrove swamps and salt marshes [11] .
3. Findings
3.1. Use of Thailand Air Force Bases to Spray and Bomb the Ho Chi Minh Trail in Cambodia and Laos
Ranch Hand aircraft utilized bases in Thailand throughout the Vietnam War (Figure 6). Operation Ranch Hand used UC-123s that were launched from airbases in Thailand including Ubon, NKP, Udorn, and Takhli on numerous occasions to
![]()
Figure 6. The Thailand Air Force Bases in Thailand. Map by Mic Greenberg. Reprinted with permission from Editor of Open Journal of Soil Science.
conduct missions against targets in Laos, Cambodia and Vietnam [12] .
In August 1963, the Thailand government requested spraying service assistance from Ranch Hand to address its locust problem. From December 29, 1968, to January 2, 1969, Ranch Hand aircraft (US Air Force) flew Agent Orange missions, out of Udorn Royal Thai Air Force base in support of the United States secret War in Cambodia and Laos [13] . On January 17, 1969, seven Ranch Hand aircraft flew to Ubon to conduct an attack on a special CIA selected target in Laos [12] [14] . From February 2 to 5, 1969, in addition to the CIA classified spray missions, Ranch Hand aircraft flew Laos’s missions. Udorn was again utilized on August 31, 1969 to conduct an operation in which Ranch Hand aircraft flew 28 sorties, using five UC-123s during a seven-day period, from Thailand (Figure 6) to target Laotian food crops with Agent Blue. Agent Blue, the arsenic based herbicide used to kill rice, was the herbicide weapon of choice when the goal was to eliminate the PAVN food supply [1] [12] [14] .
3.2. Targeted Tactical Herbicide Spraying in Cambodia
In contrast to the widespread spraying of herbicides in Laos and South Vietnam over a long period, the targeted defoliation in Cambodia resulted in a major international incident. From April 18-May 2, 1969, French and Cambodian owned rubber tree plantations in Kampong Cham Providence were sprayed with tactical herbicides [14] . At the time, the United States had no diplomatic relations with the Cambodian government of then—Prince Norodom Sihanouk. The spraying caused substantial damage. Both U.S. Government and independent inspection teams confirmed that 69,200 ha were sprayed (7% of Kampong Cham province), 9880 ha of rubber tree plantations were seriously affected. These rubber losses represented a loss of 12% of the country’s export earnings. The mystery surrounding the attack had to do with who exactly carried it out. Cambodia was officially neutral in the Vietnam War, although the eastern part of its territory had been subject to infiltration by both guerrillas on southern portions of the Ho Chi Minh Trail and US Special Forces (“Operation Daniel Boone”). The United States did not admit to using tactical herbicides. The available evidence points to Air America, the primary CIA air contractor [14] .
It is unclear who carried out the spraying over these plantations. It occurred at the time that CIA led spray missions were flown by Air America aircraft. Once the extent of the damage in Kampong Cham became apparent, Cambodian authorities made a formal complaint to the U.S. It was not the first time. Cambodia had made allegations of chemical warfare against the US beginning in 1964. “An American Quaker who was in Cambodia at the time noted, as shared by representatives of the American Friends Service Committee, Joe and Dave Elder, noted however, that the mechanism for compensating farmers for spray damage appeared to be well-established and routine”. Apparently similar incidents had happened previously. When any U.S. response was given, it was always to deny that any such attacks occurred. In 1969, the Cambodian government filed a claim for $12.2 million in damages. There never was any acceptance of responsibility by the U.S. However, the U.S. made plans to pay the claim by 1972, in order to promote “broader interests” [14] .
Anecdotal and unsubstantiated reports from residents of Mondulkiri and Ratanakiri provinces in northeast Cambodia had alleged that herbicides were sprayed in these regions during the war. There were also reports in southern Cambodia (HERBS database) of tactical herbicide spraying in the Prey Veng and Svay Rieng [14] .
Unlike South Vietnam and Laos, Cambodia was not systematically sprayed; however, the HERBS database [14] does show spray records of missions conducted in Cambodian territory. There were also incidences of spray drift of herbicides that carried over from the Ho Chi Minh Trail, which was on the Cambodian side of the border with South Vietnam.
Large-scale U.S. operations in Cambodia would not begin until the April 1970 covert invasion. A declassified memo from the U.S. Embassy in Saigon stating that “Past experience shows [Cambodian] protests [of chemical warfare] are not always accurate” begs the question of which protests were, in fact, true” [14] .
3.3. Use of Tactical Herbicides in Southeast Cambodia
Researchers at Columbia University and the Institute for Cancer Prevention [14] [15] say that the U.S. military sprayed around 154,823 liters of Agent Orange in Cambodia. However, the US government has not offered any financial assistance to affected Cambodians who struggle to afford astronomical health care bills.
Multiple investigations in the Cambodia in [16] provide evidence that the United States military sprayed commonly known as Agent Orange, on southern Cambodian villages in the 1970s. People directly exposed to Agent Orange suffered from respiratory and hearing problems and their offspring were born with cognitive impairments and crippling deformities (Figure 7).
President John F. Kennedy approved the first defoliant-spraying missions in the early 1960s, a time when tens of thousands of Communist PAVN and Viet Cong (VC) guerrillas had infiltrated and begun recruiting within U.S.-aligned South Vietnam. By 1971, the U.S. sprayed in South Vietnam nearly 72 million liters of tactical herbicides, at least 41 million liters of which was Agent Orange, to decimate the vegetation that provided the Viet Cong with cover and sustenance. The guerrillas’ infamous Ho Chi Minh Trail extended into Cambodia and
![]()
Figure 7. Four grandchildren of parents who were exposed to dioxin TCDD or arsenic during the Vietnam War. Photo credit: picture taken by Ash Annand, Newsmado. Courtesy of the Courier Mail, Brisbane, Australia.
Laos (Figure 1). Where it did, American bombs and Agent Orange and other tactical herbicides, including Agent Blue the arsenic based herbicide used to destroy the rice crop, often followed [16] .
In the 50 years since the Vietnam War, the Laotian hill tribes who were exposed to dioxin TCDD and arsenic and their offspring have had to live with the environmental damage. United States government has while admitted to and is addressing these long-lasting tactical herbicides effects in Vietnam. The U.S. is continuing to account for the U.S.’s explosive Cambodian and Laotian legacy. However, the U.S. has largely ignored the issue of dioxin (and arsenic) in these two officially neutral neighboring nations. The U.S. continues to maintain that the chemicals were not widespread there, despite records indicating otherwise [14] [16] . As a result, the U.S. has offered no assistance to affected Cambodians and Laotians, and constrained benefits to Americans who secretly served in these countries [1] without entering Vietnam (no boots on the ground) [12] but still may have been exposed to dioxin and/or arsenic [16] .
The US, in pursuing military intervention, assumes at least some responsibility for the post-conflict well-being of those affected. America’s shirking of such responsibility has become routine. In the case of the Vietnam War, the U.S. used a borderless weapon. Now when addressing those who were exposed to dioxin and arsenic they, use national borders. Leaving those exposed to dioxin and arsenic to suffer without support.
3.4. Veteran Affairs Benefits for Dioxin Affected American Veterans
In 1991, Congress passed a law promising benefits for 2.4 million dioxin-affected American veterans. The Department of Veterans Affairs has since presumed that all who served in Vietnam were exposed and are entitled to assistance. Nevertheless, this does not wholly account for dioxin’s genetic loitering. The VA makes payments to descendants of exposed veterans only when they have spina bifida or are the children of a small number of female veterans with 18 other diseases. The VA withholds these benefits from those with all other likely dioxin-caused defects. According to ProPublica, “leaves out the vast majority of vets’ ailing children” [14] [15] .
American assistance for the 4.8 million affected Vietnamese is still lacking. A single 2010 congressional earmarking provided more than $13 billion for dioxin-affected Americans, Congress has appropriated only $255 million to address the chemical’s effects on the Vietnamese. The U.S. has offered at least some support to dioxin-affected Vietnamese. No American governmental body has appropriated any funds for similarly suffering Cambodians and Laotians. However, U.S. historical records, along with academic analyses, detail what the VA called “heavy” tactical herbicide spraying in parts of Cambodia and Laos.
For example, scientists from institutions including the Institute for Cancer Prevention and Columbia University analyzed U.S. records. In a 2003 Nature article [15] scientists found during the Second Indochina War that the U.S. dispersed approximately 1.8 million liters in Laos and 154,800 liters of Agent Orange in Cambodia. The article noted that undocumented spray drift may also have occurred in Cambodia and the of spraying in Laos was determined to be incomplete.
While Randal Noller, a VA spokesperson, opted not to discuss dioxin’s Cambodian and Laotian legacy, the VA publicly concedes that these chemicals were sprayed in both countries. This contradictory American position, perhaps unsurprising, given that it affects the rural residents of two geopolitically marginal countries. However, it also affects some of the Americans who served in Cambodia and Laos [12] . The VA, seemingly based on this limited recognition of Agent Orange’s presence in Laos and Cambodia, does not extend the “automatic presumption of dioxin exposure” to the Americans who served in Cambodia and Laos but did not enter Vietnam [12] . A VA spokesperson, confirmed that the “automatic presumption of exposure” extends only to veterans who served in Vietnam. Those who served elsewhere must prove with military records that they served in Agent Orange affected areas in Cambodia and Laos. Providing this proof is difficult, though, as these CIA and military records are often still classified. Noller said the department “in most cases” concedes dioxin exposure to veterans who served in exposed parts of Cambodia and Laos.
Because of the covert nature of U.S. (CIA) operations in Cambodia and Laos, it is even unclear how many U.S. veterans served in those countries without entering Vietnam. However, there are certainly some: Gary Beatty, a retired lawyer and the president of the Thailand-Laos-Cambodia Brotherhood, a veterans’ service group, said he served in Laos and Thailand without stepping foot in Vietnam [14] [16] . The Vietnam War historian H. Bruce Franklin said in an email that many veterans fought in Laos exclusively, but that estimating how many remains difficult “because some who were on active duty were dishonestly masked as civilian contractors”.
3.5. President Nixon’s Decision
On February 22, 1969, the North Vietnamese launched a new offensive against American forces in South Vietnam from their sanctuaries in Cambodia (Figure 8) [17] . President Richard Nixon (Figure 9) took this as a personal offense and sought revenge. Nixon consulted his National Security Advisor, Dr. Henry Kissinger (Figure 10), who shared the President’s determination to respond aggressively. The Kissinger and Nixon plan would have devastating and long-lasting effects on Cambodia.
The secret plan was to bomb Cambodia (Figure 4) and destroy the North Vietnamese bases hidden in the Cambodian jungles [13] . Nixon knew that if they chose this option and it leaked to the media and public, the national chaos which he promised to end, would only spread. To maintain secrecy, the President held off on bombing Cambodia for a few weeks. This allowed the CIA to pursue a plan to bribe Cambodian officials in an attempt to end their relations with the North Vietnamese. The CIA soon found out bribes were no match for the profits
![]()
Figure 8. Distribution of herbicide exposure scores and location of North Vietnamese Army bases. The modified figure shows the distribution of herbicide exposure scores and locations of NVA bases. Reprinted with permission from Editor of Open Journal of Soil Science.
Cambodian officials were enjoying from their communist neighbors. After a Viet Cong attack on Saigon on March 15, 1969, Nixon’s impatience and frustration grew. He told Kissinger, “We cannot tolerate one more of these without hitting back…” These two decision makers, after consultation with other foreign policy and military advisors, ordered the bombing of Cambodia [5] .
Still worried about what might happen if the public received word of the bombing operation, Nixon and Kissinger worked tirelessly over the next couple of days to make sure it was kept a secret. Nixon told Kissinger “no comment, no warnings, no complaints, no protests…I mean it, not one thing to be said to anyone publicly or privately without my prior approval”, days before the first bombings. The pilots of the aircraft that carried the bombs were lied to about the location of their targets. Their missions were kept off record to make it appear that they never happened [6] . Nixon even kept the bombings a secret from high-ranking officials in the military and never consulted Congress.
On March 18, 1969, USAF Strategic Air Command (SAC) B-52 bombers (Figure 11) began carpet-bombing Cambodia. The overall covert operation was
![]()
Figure 9. President Nixon portrait. Photo credit: Jack E. Kighlinger (White House photograph). In Public Domain.
![]()
Figure 10. Dr. Henry Kissinger portrait. Photo Credit: White House photograph in public domain.
![]()
Figure 11. A B-52 aircraft at the Wright Paterson Air Force Base Museum in Dayton, Ohio. The B-52 is huge and fills most of Hanger no. 2. Photo credit: Pam Olson.
code-named “Operation Menu”, with various phases named “Breakfast”, “Lunch”, “Dinner”, “Snack”, “Supper” and “Dessert” [5] .
Several months after the start of Operation Menu five members of Congress were informed, but it was kept secret from the American people. However, the New York Times broke the story in May 1969. Dr. Henry Kissinger, President Nixon’s National Security Adviser, was reportedly outraged over the leaked information in the story and ordered the FBI to wiretap the phones of top White House aides and reporters to find the source [5] .
More reports of the secret bombing campaign eventually surfaced in the press and records of Congressional proceedings. However, but it was not until 2000 that President Bill Clinton declassified official USAF records of U.S. bombing activity over Indochina from 1964 to 1973. The official records of the CIA for the earlier 1961 to 1964 time period were not declassified.
4. Results
4.1. Early History of Cambodia
The history of the communist movement in Cambodia [17] [18] can be divided into six phases: 1) The emergence before World War II of the Indochinese Communist Party (ICP), whose members were primarily Vietnamese. 2) The 10-year struggle for independence from the French, when a separate Cambodian communist party, the Kampuchean (or Khmer) People’s Revolutionary Party (KPRP), was established under Vietnamese auspices. 3) The period following the Second Party Congress of the KPRP in 1960, when Saloth Sar gained control of its apparatus. 4) The revolutionary struggle from the initiation of the Khmer Rouge insurgency in 1967-1968 to the fall of the Lon Nol government in April 1975. 5) The Democratic Kampuchea regime from April 1975 to January 1979. 6) The period following the Third Party Congress of the KPRP in January 1979, when Hanoi effectively assumed control over Cambodia’s government and communist party [19] [20] .
4.2. Cambodian Student Group in Paris
During the late 1940s and early 1950s, Khmer students in Paris organized their own communist movement. The student movement had little, if any, connection to the hard-pressed party in their homeland. During the 1960s, these men and women returned home and took command of the party apparatus. From 1968 to 1975, they led an effective insurgency against Lon Nol and established the regime of Democratic Kampuchea [19] .
4.3. Pol Pot
Pol Pot (Figure 12) attended a technical high school in Phnom Penh before going to Paris in 1949 to study. However, he failed to obtain a degree and returned home. After returning to Cambodia in 1953, Pol Pot engaged in party work. At first, he joined with forces allied to the Viet Minh operating in the rural
![]()
Figure 12. Pol Pot portrait. Photo Credit: In public domain.
areas of Kampong Cham Province. After the end of the war, he moved to Phnom Penh under Tou Samouth’s “urban committee”. There he became an important point of contact between the underground secret communist movement and the above-ground parties of the left [20] .
In 1965, Pol Pot made a visit of several months to China and North Vietnam [21] . From the 1950s on, Pol Pot had made frequent visits to the People’s Republic of China, receiving political and military training, on the theory of dictatorship of the proletariat, from the personnel of the CCP [22] [23] . From November 1965 to February 1966, Pol Pot received training from high-ranking CCP on topics such as the communist revolution in China, Communist International, and class conflicts.
4.5. Kampuchea
Pol Pot as the leader of the Khmer Rouge, during its days as an insurgent movement, came to admire the tribes in Cambodia’s rural northeast. These tribes were self-sufficient and lived on the goods they produced through subsistence farming [20] [21] . The tribes, he felt, were like communes in that they worked together, shared in the spoils of their labor and were untainted by the evils of wealth, money, and religion, the latter being the Buddhism common in Cambodia’s cities.
In 1968, the Khmer Rouge was officially formed and launched a national insurgency across Cambodia. The party finally openly declared itself to be the Communist Party of Kampuchea after the insurgency had grown stronger [21] . Once installed as the country’s leader by the Khmer Rouge, Pol Pot and his loyal forces quickly set about remaking Cambodia. They renamed Cambodia calling it Kampuchea, in the model of the rural tribes, with the hopes of creating a communist-style, agricultural utopia.
Although Pol Pot and the Khmer Rouge did not take control until the mid-1970s. The roots of the Pol Pot and Khmer Rouge takeover can be traced back to the 1960s. In the early-1970s the communist insurgency (Khmer Rouge) became active in Cambodia, at a time when the country was still ruled by a monarch [22] .
During the 1960s, the Khmer Rouge operated as the armed wing of the Communist Party of Kampuchea, the name the party used for Cambodia. Operating primarily in remote jungle and mountain areas in the northeast of the country, near its border with Vietnam, which at the time was embroiled in its own civil war, the Khmer Rouge did not have popular support across Cambodia, particularly in the cities, including the capital Phnom Penh.
A 1970 military coup led to the ouster of Cambodia’s ruling monarch, Prince Norodom Sihanouk, The Khmer Rouge decided to join forces with the deposed leader and form a political coalition [22] . Since the monarch had been popular, among city-dwelling Cambodians, the Khmer Rouge began to acquire more and more support.
On 29 March 1970, the North Vietnamese Army launched an offensive against the Cambodian Army. The North Vietnamese Army quickly overran large parts of eastern Cambodia reaching to within 24 km of Phnom Penh (Figure 13) before being pushed back. By June, three months after the removal of Sihanouk, they had swept Cambodian government forces from the entire northeastern third of the country (which opened the door for the Khmer Rouge and Pol Pot). After defeating the Cambodia military forces, the North Vietnamese Army turned the newly won territories over to the local insurgents (Khmer Rouge). The Khmer Rouge also established “liberated” areas in the south and the southwestern parts of Cambodia, where they operated independently of the North Vietnamese military [24] .
After Sihanouk (leader of Cambodia government) showed his support for the Khmer Rouge, by visiting them in the field, the Khmer Rouge ranks grew from 6000 to 50,000 fighters. On 17 April 1975, there was the Fall of Phnom Penh (Figure 14), as the Khmer Rouge captured the capital. During the civil war, unparalleled atrocities were executed on both sides [25] .
For the next five years, a civil war between the right-leaning Cambodia military, which had led the coup, and those supporting the alliance of Prince Norodom and the Khmer Rouge raged in Cambodia. Eventually, the Khmer Rouge side seized the advantage in the conflict, after gaining control of increasing amounts of territory in the Cambodian countryside [19] [20] .
In 1975, Khmer Rouge fighters invaded Phnom Penh and took over the city (Figure 14). With the capital in its grasp, the Khmer Rouge had won the civil war and, thus, ruled the country. Notably, the Khmer Rouge opted not to restore power to Prince Norodom, but instead handed power to the leader of the Khmer Rouge, Pol Pot. Prince Norodom was forced to live in exile.
![]()
Figure 13. Ho Chi Minh trail pathways through Cambodia to Vietnam. Map by Cruz Dragosavac.
![]()
Figure 14. Was 21. Khmer Rouge entering Phnom Penh on April 17, 1975, Photo Credit: STOBERG/AFP/Gettyimages.
4.6. Khmer Rouge
During the late 1960s, the Khmer Rouge Army was slowly built up in the jungles of eastern Cambodia, supported by the North Vietnamese Army, the Viet Cong, the Pathet Lao, and the Chinese Communist Party (CPP) [22] [23] [26] . Although it originally fought against Sihanouk, the Khmer Rouge reversed its position and supported Sihanouk on the advice of the CCP after Lon Nol who established the pro-American Khmer Republic [26] overthrew him in a 1970 coup. Despite a massive American bombing campaign (Operation Freedom Deal) (Figure 15) against them, the Khmer Rouge won the Cambodian Civil War when they captured the Cambodian capital, Phnom Penh, and overthrew the Khmer Republic in 1975. Following their victory, the Khmer Rouge led by Pol Pot, immediately set about forcibly evacuating the country’s major cities. In 1976, they renamed Cambodia the Democratic Kampuchea.
The Khmer Rouge regime was highly totalitarian, autocratic and repressive. Many deaths resulted from the regime’s social engineering policies. The “Moha Lout Plaoh” was an imitation of China’s Great Leap Forward which had caused the Great Chinese Famine [22] [27] [28] . The Khmer Rouge’s attempts at agricultural reform through collectivization similarly led to widespread famine. The Khmer Rouge insistence on absolute self-sufficiency, including in the supply of medicine, led to the death of many thousands from treatable diseases such as malaria. The Khmer Rouge regime murdered hundreds of thousands of their perceived political opponents. Its racist emphasis on national purity resulted in the genocide of Cambodian minorities. Summary torture and executions were carried out by its cadres against perceived subversive elements and during genocidal purges of its own ranks between 1975 and 1978 [29] . Ultimately, the Cambodian genocide led to the deaths of 1.5 to 2 million people or approximately 25% of Cambodia’s population [30] .
![]()
Figure 15. President Nixon at a White House briefing. Photo Credit: Jack E. Kighlinger.
In the 1970s, the Khmer Rouge were largely funded and supported by the Chinese Communist Party. After receiving approval from Mao Zedong, it is estimated that at least 90% of the foreign aid, provided to the Khmer Rouge, came from China [31] [32] .
4.7. The 1969 Republic of Vietnam (RVN) and United States Campaign to Eliminate the People’s Army of Vietnam (PAVN) and the Viet Cong (VC) Bases in Cambodia
The Cambodian campaign (also known as the Cambodian invasion or Cambodian incursion) was a brief series of military operations conducted in eastern Cambodia in 1969 by South Vietnam and the United States (Figure 15) as the Cambodian Civil War an extension of the Vietnam War. Thirteen major operations were conducted by the Army of the Republic of Vietnam (ARVN) between 29 April and 22 July and by U.S. forces between 1 May and 30 June 1970 (Figure 16).
The goal of the campaign was to defeat of the approximately 40,000 troops of the People’s Army of Vietnam (PAVN) and the Viet Cong (VC) in the eastern border regions of Cambodia. Cambodian neutrality and military weakness made its territory a safe zone where PAVN/VC forces could establish bases for operations over the border from South Vietnam. With the U.S. shifting toward a policy of Vietnamization and withdrawal, it sought to shore up the Republic of Vietnam government by eliminating the cross-border threat.
A change in the Cambodian government leadership allowed an opportunity to
![]()
Figure 16. ARVN troops entering Cambodia. Photo Credit: Defense Department Employee or soldier. In public domain.
destroy the NVA bases in 1970, when Prince Norodom Sihanouk was deposed and replaced by pro-U.S. General Lon Nol. A series of South Vietnamese-Khmer Republic operations captured several towns, but the PAVN/VC military and political leadership narrowly escaped the cordon. The operation was partly a response to a PAVN offensive on 29 March against the Cambodian Army that captured large parts of eastern Cambodia in the wake of these operations. Allied military operations failed to eliminate the PAVN/VC troops or to capture their elusive headquarters, known as the Central Office for South Vietnam (COSVN) as they had left a month prior. However, they did capture a haul of weapons, material and food (Figure 17) in Cambodia promptly claimed the mission a success.
The PAVN had been utilizing large sections of relatively unpopulated eastern Cambodia as sanctuaries into which they could withdraw from the conflict in South Vietnam to rest and reorganize without being attacked. These base areas were also utilized by the PAVN and VC to store weapons and other material that had been transported on a large scale into the region on the Sihanouk Trail. PAVN forces had begun moving through Cambodian territory as early as 1963 [33] [34] .
Cambodian neutrality had already been violated by South Vietnamese forces in pursuit of political-military factions opposed to the regime of Ngô Đình Diệm in the late 1950s and early 1960s [30] . In 1966, Prince Norodom Sihanouk, ruler of Cambodia, convinced of eventual communist victory in Southeast Asia and fearful for the future of his rule, had concluded an agreement with the People’s Republic of China. The agreement allowed the establishment of permanent
![]()
Figure 17. Cambodian civilians bag up captured North Vietnamese rice. Photo Credit: William H. Hammond. The US Army. In public domain.
communist bases on Cambodian soil and the use of the Cambodian port of Sihanoukville for resupply [34] [35] .
The new commander of the U.S. Military Assistance Command Vietnam (MACV), General Creighton W. Abrams, recommended, to President Richard M. Nixon shortly after Nixon’s inauguration, that the Cambodian base areas be bombed by B-52 Stratofortress bombers [36] . Nixon initially refused, but the breaking point came with the launching of PAVN’s Tet 1968 Offensive in South Vietnam. Nixon, angered at what he perceived as a violation of the “agreement” with Hanoi after the cessation of the bombing of North Vietnam, authorized the covert air campaign [36] . The first mission of Operation Menu was dispatched on 18 March and by the time it was completed 14 months later more than 3000 sorties had been flown and 108,000 tons of bombs had been dropped on eastern Cambodia [36] .
In particular, Nixon believed that a spectacular military action that would prove “we are still serious about our commitment in Vietnam” might force the North Vietnamese to conclude the Paris peace talks in a manner satisfactory to American interests [37] . In 1969, Nixon had pulled out 25,000 U.S. troops from South Vietnam and was planning to pull out 150,000 in the very near future [37] . The first withdrawal of 1969 had led to an increase in PAVN/VC activities in the Saigon area, and General Abrams had warned Nixon to pull out another 150,000 troops without eliminating the PAVN/VC bases over the border in Cambodia would create an untenable military situation [37] . Even before the coup against Sihanouk, Nixon was already inclined to invade Cambodia [37] .
During a televised address on 20 April, Nixon announced the withdrawal of 150,200 U.S. troops from South Vietnam during the year as part of the Vietnamization program [38] . This planned withdrawal implied restrictions on any offensive U.S. action in Cambodia. By early 1970, MACV still maintained 330,648 U.S. Army and 55,039 Marine Corps troops in South Vietnam, most of whom were concentrated in 81 infantry and tank battalions [39] .
On 22 April Nixon authorized the planning of a South Vietnamese incursion into the Parrot’s Beak (named for its perceived shape on a map (Figure 13)), believing that “Giving the South Vietnamese an operation of their own would be a major boost to their morale as well as provide a practical demonstration of the success of Vietnamization” [34] . At the meeting of 22 April, both Rogers and the Secretary of Defense Melvin Laird proposed waiting to see if the Lon Nol regime could manage to survive on its own [38] . Kissinger took an aggressive line, favoring having the ARVN invade Cambodia with American air support [38] .
The main problems were the pressure of time and Nixon’s desire for secrecy. The Southeast Asia monsoon, whose heavy rains would hamper operations, was only two months away. President Nixon order the U.S. State Department not to notify the Cambodian desk at the U.S. Saigon Embassy, the Phnom Penh embassy, nor Lon Nol of the planning. Operational security was as tight as General Abrams could make it.
On 30 April 1970, President Nixon announced the Cambodia attack. In a televised address to the nation (Figure 15), he justified the attack as a necessary response to North Vietnamese aggression. The joint U.S./ARVN campaign would begin on 1 May with the stated goals of; reducing allied casualties in South Vietnam; assuring the continued withdrawal of U.S. forces; and enhancing the U.S./Saigon government position at the peace negotiations in Paris [37] . The task of providing a legal justification was assigned to William Rehnquist, the assistant attorney general, who wrote a legal brief saying “in times of war the president had the right to deploy troops in conflict with foreign powers at their own initiative” [37] .
President had Kissinger inform key Senators of the plans to invade Cambodia [38] . In this way, Nixon could say he did inform at least some leaders of Congress about what was being planned. Congress as a body was kept uninformed of the planned invasion of Cambodia [37] .
On 29 April, press reports stated that ARVN troops had entered the “Parrot’s Beak” area (Figure 16), leading to demands from anti-war senators and congressmen that the president should promise no American troops would be involved. The only White House response was to say the president would be giving a speech the next day [38] .
In order to keep the campaign as low-key as possible, General Abrams had suggested that the commencement of the incursion be routinely announced from Saigon. At 21:00 on 30 April, however, Nixon appeared on all three U.S. television networks to announce that “it is not our power but our will and character that is being tested tonight” and that “the time has come for action”. Nixon’s speech began 90 minutes after American troops entered the “Fishhook” area [38] . He announced his decision to launch American forces (Figure 18) into Cambodia with the special objective of capturing COSVN, “the headquarters of the entire communist military operation (Figure 19) in South Vietnam” [34] .
Nixon’s speech on national television on 30 April 1970 was called “vintage Nixon” by Kissinger [34] . Nixon announced that nothing less than America’s status as a world power was at stake, saying he had spurned “all political considerations”, as he maintained he rather be a one-term president than “be a two-term president at the cost of seeing America become a second-rate power” [38] .
Nixon stated “if, when the chips are down, the world’s most powerful nation, the United States of America, acts like a pitiful helpless giant, then the forces of totalitarianism and anarchy will threaten free nations and free institutions throughout the world” [38] .
4.8. Between 29 April and 1 July 1970, ARVN and US Army Attacked beyond Cambodian Borders to Seek out Enemy Troops
On 17 April, General Abrams requested that Nixon approve Operation Patio, covert tactical airstrikes in support of MACV-SOG reconnaissance elements in
![]()
Figure 18. Land mines clearing operation by US Army Engineers entering Cambodia. Photo Credit Donn A. Starry. In public domain.
![]()
Figure 19. Men of Company “D”, 3rd Battalion, 22nd Infantry, 25th Infantry Division. Loading captured PAVN documents into a helicopter. Photo credit: The U.S Army.
Cambodia (Figure 20). This authorization was given and permitted U.S. aircraft to penetrate 21 km into northeastern Cambodia (Figure 21). This boundary was extended to 47 km along the entire frontier on 25 April. Patio was terminated on 18 May after 156 sorties had been flown [40] . The last mission was flown on 26 May [41] .
During the incursion, U.S. and ARVN ground units were supported by 9878 aerial sorties (6012 USAF/2966 RVNAF), an average of 210 per day [42] . The 30th of May saw the inauguration of Operation Freedom Deal, a continuous U.S.
![]()
Figure 20. Ubon Air Force base in Thailand. Reprinted with permission from Editor of Open Journal of Soil Science.
![]()
Figure 21. Hitting NVA and VC sanctuaries in Cambodia exhibit at the Wright Paterson Air Force Base Museum in Dayton, Ohio. Photo credit. Pam Olson.
aerial interdiction campaign conducted in Cambodia. These missions were limited to a distance of 48 kilometers between the South Vietnamese border and the Mekong River [36] . Within two months, the operational limit was extended past the Mekong and U.S. tactical aircraft were directly supporting Cambodian forces in the field [36] . These missions were officially denied by the U.S. and false coordinates were given in official reports to hide their existence [40] . Department of Defense records indicated that out of more than 8000 combat sorties flown in Cambodia between July 1970 and February 1971, approximately 40 percent were flown outside the authorized boundary [40] .
PAVN forces then seized Laotian towns as a response to the loss of their Cambodian supply route (Figure 1). What had been a 97 km corridor was expanded in width to 140 km which opened the entire length of the Kong River system into Cambodia [43] .
Reaction in the U.S. Congress to the incursion was swift. Senators proposed an amendment to the Foreign Military Sales Act of 1971 that would have cut off funding not only for U.S. ground operations and advisors in Cambodia. The amendment would also have ended U.S. air support for Cambodian forces [44] . On 30 June the U.S. Senate passed the act with the amendment included. The bill was defeated in the House of Representatives after U.S. forces were withdrawn from Cambodia as scheduled. However, the newly amended act did rescind the Southeast Asia Resolution (known as the Gulf of Tonkin Resolution) under which Presidents Johnson and Nixon had conducted military operations for seven years without a declaration of war [45] .
4.9. The 1973 to 1975 Withdrawal from Cambodia
The Paris Peace Accords were signed on 27 January 1973 by the governments of North Vietnam, South Vietnam, and the United States with the intent to establish peace in Vietnam [45] . The accords effectively ended United States military operations in North Vietnam and South Vietnam. Cambodia and Laos were not signatories to the Paris agreement and remained in a state of war.
In 1973, Dr. Henry Kissinger traveled to Hanoi to discuss establishing diplomatic relations between the U.S. and North Vietnam. An International Commission of Control and Supervision (ICCS) was established to supervise the implementation of the peace accords. While agreeing to withdraw from Vietnam, the U.S. increased the air war over Cambodia in an ill-fated attempt to support General Lon Nol and to keep Phnom Penh from falling to the communist Khmer Rouge under Pol Pot. Operation Homecoming resulted in the return of U.S. prisoners-of-war while the U.S. Navy and Marine Corps de-mined Hai Phong Harbor and coastal North Vietnam. Domestically, the U.S. Congress cut in half the U.S. military and economic assistance to South Vietnam.
In Cambodia, the USAF carried out a massive bombing campaign to prevent the Khmer Rouge from taking over the country. Congressional pressure in Washington grew against these bombings. On 30 June 1973, the United States Congress passed Public Law PL 93 - 50 and 93 - 52, which cut off all funds for combat in Cambodia and all of Indochina effective 15 August 1973. Air strikes by the USAF peaked just before the deadline, as the Khmer National Armed Forces engaged a force of about 10,000 Khmer Rouge soldiers encircling Phnom Penh [31] [32] .
At 11:00 15 August 1973, the congressionally mandated cutoff went into effect, ending the combat activities over the skies of Cambodia. The last of the Constant Guard F-4 augmentation forces were released in September 1973. On April 11/12, Ubon (Thailand) (Figure 20) served as a staging base for eight HH-53s of the 40th Aerospace Rescue and Recovery Squadron as they took part in Operation Eagle Pull, an evacuation of U.S. civilians from Phnom Penh [31] .
Declaring 1975 “Year Zero” in the country, Pol Pot isolated Kampuchea from the global community. He resettled hundreds of thousands of the country’s city-dwellers in rural farming communes and abolished the country’s currency. He also outlawed the ownership of private property and the practice of religion in the new nation.
4.10. Kampuchea Was Established by Khmer Rouge in 1975 and Overthrown by the Vietnamese Army in 1979
In April 1975, Khmer Rouge seized power in Cambodia, and in January 1976, Democratic Kampuchea was established. During the Cambodian, the CCP was the main international patron of the Khmer Rouge, supplying “more than 15,000 military advisers” and most of its external aid [46] . It is estimated that at least 90% of the foreign aid to Khmer Rouge came from China. The Vietnamese Army overthrew democratic Kampuchea in January 1979, and the Khmer Rouge fled to Thailand.
4.11. Cambodian-Vietnam War
Fearing a Vietnamese attack, Pol Pot ordered a pre-emptive invasion of Vietnam on 18 April 1978. His Cambodian forces, supported by China, crossed the border and looted nearby villages, mostly in the border town of Ba Chúc. Of the 3157 civilians who had lived in Ba Chúc [46] , only two survived the massacre. The Vietnamese Army [47] repelled these Cambodian forces.
After several years of border conflict and the flood of refugees fleeing Kampuchea, relations between Kampuchea and Vietnam collapsed by December 1978. The Vietnam Army along with the Kampuchean United Front for National Salvation [48] invaded Cambodia on 25 December 1978 and captured Phnom Penh on 7 January 1979. Despite a traditional Cambodian fear of Vietnamese domination, defecting Khmer Rouge activists assisted the Vietnamese and with Vietnam’s approval became the core of the new People’s Republic of Kampuchea. The new government was quickly dismissed by the Khmer Rouge and China as a “puppet government” [49] . At the same time, the Khmer Rouge retreated to the west and continued to control areas adjacent to the Thai border for the next decade [49] . These Khmer Rouge bases were not self-sufficient and were funded by military assistance from China, diamond and timber smuggling, channeled by means of the Thai military, and food smuggled from markets across the border in Thailand [50] .
4.12. Cambodian Genocide
Workers on the farm collectives established by Pol Pot in late 1970s soon began suffering from the effects of overwork and lack of food. Hundreds of thousands died from disease, starvation or damage to their bodies sustained during backbreaking work or abuse from the ruthless Khmer Rouge guards overseeing the camps. Pol Pot’s regime also executed thousands of people it had deemed as enemies of the state (Figure 22, Figure 23, Figure 24). Those seen as intellectuals, or potential leaders of a revolutionary movement, were also executed. Legend has it that some were executed for merely appearing to be intellectuals, by wearing glasses or being able to speak a foreign language. As part of this effort, hundreds of thousands of the educated, middle-class Cambodians were tortured and executed in special centers established in the cities (Figure 23). The
![]()
Figure 22. This Killing Fields was located at a temple near Kampong Cham. One of the more than 100 Killing Fields in Cambodia.
![]()
Figure 23. One of the Killing Fields was located at the base of a temple near Kampong Cham.
![]()
Figure 24. The skulls recovered from a Killing Fields. Photo Credit: Malcom P. Chapman, Gettyimages.
most infamous of which was Tuol Sleng jail in Phnom Penh, where nearly 17,000 men, women and children were imprisoned during the regime’s four years in power. During the Cambodian Genocide, an estimated 1.7 to 2.2 million Cambodians died during Pol Pot’s time in charge of the country.
4.13. Removal from Power of Khmer Rouge
The Khmer Rouge regime was removed from power in 1979 when Vietnam Army invaded Cambodia and quickly destroyed most of the Khmer Rouge’s forces. The Khmer Rouge then fled to Thailand where the Thai government saw them as a buffer force against the Communist Vietnamese [31] . The Khmer Rouge continued to fight against the Vietnamese and the government of the new People’s Republic of Kampuchea until the end of the war in 1989. The Cambodian governments-in-exile (the Khmer Rouge) held onto Cambodia’s United Nations seat (with considerable international support) until 1993. The monarchy was restored and the Cambodian state name was changed to the Kingdom of Cambodia. A year later, a government amnesty program resulted in the surrender of thousands of Khmer Rouge guerrillas.
In 1996, a new political party called the Democratic National Union Movement was formed by Leng Sary after he was granted amnesty for his role as the deputy leader of the Khmer Rouge [31] . The organization was largely dissolved by the mid-1990s and finally surrendered completely in 1999. In 2014, two Khmer Rouge leaders were jailed for life by a United Nations-backed court. They had been found guilty of crimes against humanity for their roles in the Khmer Rouge’s genocidal campaign.
From 1975 to 1979, the Khmer Rouge a brutal regime ruled Cambodia, under the leadership of Marxist dictator Pol Pot. Pol Pot’s had attempted to create a Cambodian “master race” through social engineering. Ultimately led to the deaths of more than 2 million people in the Southeast Asian country [32] . Those killed were either executed as enemies of the regime, or died from starvation, disease or from being overwork. Historically, this period, as shown in the film The Killing Fields, has come to be known as the Cambodian Genocide.
The Vietnamese Army invaded Cambodia in 1979, removed Pol Pot and the Khmer Rouge from power, after a series of violent battles on the border between the two countries. Pol Pot, with support from China, had sought to extend his influence into the newly unified Vietnam. However, his forces were quickly rebuffed. After the invasion, Pol Pot and his Khmer Rouge fighters retreated to remote areas of the country. They remained active as an insurgency but with declining influence for much of the 1980s, Vietnam retained control of Cambodia, with a military presence, over the objections of the United States. During the decades since the fall of the Khmer Rouge, Cambodia has gradually re-established ties with the world community, although the country still faces problems, including widespread poverty and illiteracy. Prince Norodom returned to govern Cambodia in 1993, although he now rules under a constitutional monarchy.
Pol Pot himself lived in the rural northeast of the country until 1997, when the Khmer Rouge tried him for his crimes against the state [50] . The trial was seen as being mostly for show, however, and the former dictator died while under house arrest in his jungle home. The stories of the suffering of the Cambodian people at the hands of Pol Pot and the Khmer Rouge have continued to garnered worldwide attention via the 1984 movie the Killing Fields [31] and an account of the atrocities based on the book The Death and Life of Dith Pran by journalist Sydney Schanberg [51] .
4.14. Killing Fields
According to a 2001 academic source, the most widely accepted estimates of excess deaths under the Khmer Rouge range from 1.5 million to 2 million, although figures as low as 1 million and as high as 3 million have been cited. Accepted estimates of executions range from 500,000 to 1 million (Figure 25), “a third to one half of excess mortality during the period” [52] . A 2013 academic source (citing research from 2009) indicates that execution may have accounted for as much as 60% of the total, with 23,745 mass graves containing approximately 1.3 million suspected victims of execution [53] .
5. Summary
The United States sprayed and bombed the Ho Chi Minh Trail starting in 1959 and invaded Cambodia in 1969. On February 22, 1969, the PAVN launched a new offensive against American forces in South Vietnam from their sanctuaries in Cambodia. President Richard Nixon, acting on the advice of his National Security Advisor, Dr. Henry Kissinger, created a solution, which was to spray and bomb Cambodia, a neutral country, to eliminate the PAVN sanctuary base
![]()
Figure 25. A collection of skulls at a Killing fields museum. Photo Credit: Malcom P. Chapman, Gettyimages.
camps. The U.S. bombing campaign increased the Cambodian civilian death toll and resulted in the insurgency (Khmer Rouge) being able to recruit support from the local civilians. This created a domino effect-strengthening the popularity of the Khmer Rouge, led by Pol Pot, enabling him to win the Cambodian Civil War, capture the Cambodian capital of Phnom Penh, and overthrow the Khmer Republic in 1975.
The relationship between the massive carpet bombing and spraying of Cambodia by the United States and the growth of the Khmer Rouge, in terms of recruitment and popular support, has been a matter of interest to historians. Some scholars have cited the United States intervention and bombing campaign (from 1965 to 1973) as a significant factor, which led to increased support for the Khmer Rouge among the Cambodian peasantry. The carpet-bombing of Cambodia lasted until August 1973. It devastated the countryside and the chaos and upheaval it unleashed played a big part in the installation of the genocidal Khmer Rouge regime led by Pol Pot. The Khmer Rouge was responsible for the deaths of up to two million Cambodians through executions, forced labor and starvation.
The Khmer Rouge was a brutal regime that ruled Cambodia, under the leadership of Marxist dictator Pol Pot, from 1975 to 1979. Pol Pot’s attempts to create a Cambodian “master race” through social engineering ultimately led to the deaths of more than 2 million people in the Southeast Asian country. Those killed were either executed as enemies of the regime, or died from starvation, disease or overwork. The instability of Cambodia lead to the rise of the Khmer Rouge and the Killing Fields. In 1979, it was Vietnam military, and not the United States military, that ended the Khmer Rouge genocide.
While the United States government did not intend to destabilize Cambodia, the 1959 Secret War on the Ho Chi Minh Trail, which resulted in the killing of 100,000 to 600,000 Cambodians. An additional 1.3 million Cambodians died between 1970 to 1973 as a result of the President Nixon and Henry Kissinger’s decision to bomb the PAVN and VC base camps in Cambodia. Both secret wars destabilized the central Cambodian government and lead to the rise of Pol Pot and the Khmer Rouge. The Khmer Rouge moved the Cambodians out of the cities and they had to survive using subsistence farming techniques. Pol Pot attempted to create a “master race” via the more than 100 Killing Fields, which lead to the deaths of up to two million Cambodians. The total loss of life in Cambodia between 1959 and 1979 was approximately 4 million. The Cambodians paid a very high price for the United States government’s two secret wars which extended its Vietnam War into Cambodia in an attempt to stop the southward spread of communism in Southeast Asia.
Acknowledgements
This research study was conducted with the support and approval of the Merry Band of Retirees Research Committee. The team includes five US Vietnam veterans, two Vietnam Era veteran, two US Army veterans, and four Agricultural College Professors. Our team mission is to conduct soil, water, agricultural and natural resource management scientific research; the synthesis and analysis of current and historical documents and scientific evidence relevant to the legacies of war, especially the US Vietnam War; and the preparation and publication of peer reviewed papers of interest and value to those who lead and served in the US military, especially Vietnam Era veterans, their families and the general public. The legacies of the US Vietnam War had impacts far beyond front line veterans; encompassing civilian and military personnel who manufactured, transported and handled the tactical herbicides—arsenic-based Agent Blue and Agent Orange (and other 2, 4, 5-T herbicides) contaminated with the dioxin TCDD; those who came in contact with contaminated aircraft and other equipment; and the residual effects of these chemicals on southern Vietnam soil and water and the health of people who continue to work these lands for their living.
NOTES
*Kenneth R. Olson is U.S. Army Vietnam Era Veteran and Professor Emeritus of Soil Science.
#David R. Speidel is a former USDA Resource Conservationist and Agricultural Consultant with Natural Resource Conservation Service and Foreign Agricultural Service, Benton, Missouri, USA.