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During the Vietnam War, Thailand was one of the places where GIs on leave went for a much-welcome break from the fighting. But Thailand’s multifaceted support for U.S. combat operations in Indochina—Vietnam, Cambodia and Laos—was a far more important contribution.

The Southeast Asian kingdom, bordered on the east by embattled Cambodia and Laos, was home to major U.S. Air Force bases used to launch attack, escort, bombing and reconnaissance missions throughout the war zone. Thailand also provided boots on the ground to assist the U.S. and its other allies in the fight, which included South Korea, Australia, New Zealand and The Philippines.

By the end of the war, more than 40,000 Thai military personnel had served in Vietnam, suffering losses of 351 killed and 1,358 wounded. Most Thai forces saw action in open and covert operations conducted primarily in Laos—although Thailand’s Queen’s Cobras and Black Panthers did fight in South Vietnam.

In a 1967 interview on “ABC Scope,” a weekly TV news program, Foreign Minister Thanat Khoman explained that Thailand’s reasons for supporting the war effort had both security and economic underpinnings. His country’s common borders with Laos and Cambodia, each threatened by communist insurgencies, put the kingdom in a dangerous position that endangered its own survival. The instability on the long eastern border also affected Thailand’s economy.

In 1953, the Viet Minh, the communist-dominated organization fighting at the time for Vietnam’s independence from France, invaded French-controlled northern and eastern Laos, where the communist Pathet Lao insurgency was emerging, a direct threat to Thailand. In 1954, after a defeated France ended its rule of Indochina, the Thai government pushed for pro-Western Laos to act as a buffer between Thailand and the newly created communist North Vietnam.

Unlike other countries in the region, Thailand, known as Siam until 1939, had never been under the control of a European colonial power, a source of great pride in the country. Thailand therefore had not experienced the anti-colonialist revolutionary fervor that drove communist-backed independence movements elsewhere in Southeast Asia.

Even so, Thailand still feared the region’s spreading communist movement—the Viet Cong in Vietnam, the Khmer Rouge in Cambodia and the Pathet Lao in Laos—which proselytized an ideology that imperiled Thailand’s monarchial form of government, culture and dominant religion. The Thais believed it was their duty to fight against the communists who were destroying Buddhist temples in their quest for control of Cambodia and Laos.

In the late 1950s and the early 1960s, U.S. leaders in Washington, committed to a “containment” policy to stop the spread of Soviet-style communism, were deeply concerned about communist expansion in Southeast Asia. They had “lost China” to Mao Zedong’s communists in 1949 and just narrowly defeated the North Korean/Chinese attempt to conquer democratic South Korea in 1950-53. Much of America’s Cold War leadership adhered to the “domino theory”—if even one Southeast Asian country fell, the rest would inevitably drop like tumbling dominoes. 

The Udorn base’s Air America compound, shown around 1965, is crowded with T-28 Trojan aircraft likely destined for a CIA covert operation. (Courtesy Randy Kim)
The Udorn base’s Air America compound, shown around 1965, is crowded with T-28 Trojan aircraft likely destined for a CIA covert operation. (Courtesy Randy Kim)

President Dwight D. Eisenhower and his successor, John F. Kennedy, would not allow Laos to fall to communists, and their administrations realized that Thailand’s active cooperation was vital in that effort. They hoped to make Thailand an anti-communist stronghold in the region through economic support, military aid and troop training.

“In 1951, the CIA sent case officer Bill Lair to Thailand,” James Parker, a CIA case officer in Laos 1971-73, said in a 2016 interview with the Bangkok Post. “He was given the job of training some Thai border police as a ready reaction force to counter communist incursions across the Thai borders.”

In 1953, Eisenhower’s selection for a new ambassador to Thailand was William Donovan, who had led the World War II spy agency, the Office of Strategic Services, forerunner of the CIA, created in 1947.

Like the U.S., Thailand was concerned with events in Laos, which had been its buffer against intervention from both China and Vietnam. If Laos fell, the door was wide open for communism to infiltrate Thailand. Particularly disconcerting, Thailand was home to 50,000 ethnic Vietnamese, many of them sympathetic to North Vietnamese leader Ho Chi Minh and his communist ideology. The CIA estimated that some 3,200 known communist guerrillas, mostly ethnic Chinese and Vietnamese, were operating in Thailand by the mid-1960s. The Thais understood that the only answer to this problem was to join forces with the United States.

By the late 1950s Pathet Lao forces, linked with the communists in North Vietnam and China, were gaining more and more control of territory in Laos, which was struggling to defeat the insurgents. To counter the Pathet Lao, the CIA developed an anti-communist paramilitary force in Laos and trained Thai army and police units in guerrilla warfare. For the first time, Thai forces began covert operations into Laos under the direction of the CIA.

Those forces were a way to confront the communists in Laos without the direct action of American troops. However, by 1959 U.S. Army Special Forces, the Green Berets, had covertly entered Laos and begun training Meo tribesman to fight the Pathet Lao.

Thailand’s situation worsened in 1961 as North Vietnam, with assistance from the Soviet Union and China, provided support to communist operations in South Vietnam, Cambodia, Laos and parts of Thailand. The Communist Party of Thailand led an armed revolt in the northeastern provinces of the country. In response, Thailand deployed 30,000 troops, wresting an uneasy control of the area, which lasted throughout the war.

The United States gave both economic and military aid to Thailand, and in return Thailand provided both air and ground bases for the Americans. Between 1961 and 1965 seven Thailand bases saw the arrival of American warplanes. Eventually, they housed more than 400 aircraft and 25,000 military personnel.

Although technically Thailand-owned bases for the Royal Thai naval and air forces, the installations served as headquarters for U.S. Air Force units that used them for operations throughout Indochina. Some 80 percent of the American airstrikes launched against North Vietnam and its guerrilla camps in the region came from those air bases.

CIA operatives, under the guise of “military advisers,” began training Lao troops and pilots in Thailand, while Thai special forces continued their covert missions into Laos. Specially trained Thai operators “volunteered” to join the Royal Laotian Army and complemented the facade with Laotian uniforms and ID cards. By early 1962, about 60 Thais had “enlisted” in Lao units; all on the CIA payroll.

The CIA also began training Hmong tribesmen from the mountains of Laos and Vietnam to fight the communists under an authorization that Eisenhower signed in December 1960. The training camps were in Thailand. With much of the training and logistics coming from the CIA, the new forces were prepared to battle the enemy through covert action.

The American aid did not go unnoticed by the communist side. Tensions ramped up when the Pathet Lao attacked in spring 1962 and took control of the Nam Tha river valley in northwestern Thailand. Fearing an all-out attack, Thailand sent thousands of troops to repel the attackers.

In May 1962, Kennedy deployed 6,500 Marines to bolster the Thai forces (although he decided in July to withdraw them because of concerns about establishing a long-term commitment). Thai operatives, trained by the CIA and U.S. Special Forces, entered Laos and engaged Pathet Lao units, driving them back and securing the northern part of the country against further encroachments.

In the meantime, American technicians and engineers worked on improvements at Thai air bases. Air America, a U.S. government-owned airline secretly supporting CIA missions, flew from those bases into Laos and Vietnam, delivering supplies to covert groups working with anti-communist forces.

Despite those efforts, by 1962 the reports coming out of Laos were not good. The North Vietnamese were using a network of routes that ran through the country, collectively known as the Ho Chi Minh Trail, to smuggle arms and fighters into South Vietnam. Intelligence estimates indicated 7,000 to 9,000 North Vietnamese Army troops were in Laos.

Thai army soldiers in the Queen’s Cobras unit look at Viet Cong killed during a December 1967 battle east of Saigon. Thailand sent thousands of troops into South Vietnam to assist in the fight against communist forces. (Bettmann/Getty Images)
Thai army soldiers in the Queen’s Cobras unit look at Viet Cong killed during a December 1967 battle east of Saigon. Thailand sent thousands of troops into South Vietnam to assist in the fight against communist forces. (Bettmann/Getty Images)

In March 1964 American planes flying out of Thai bases started bombing Viet Cong camps and supply routes in Laos. Those bombers were not allowed to strike North Vietnam directly. That changed after the Gulf of Tonkin incident in August 1964, when North Vietnamese torpedo boats attacked an American destroyer, and President Lyndon B. Johnson ordered retaliatory airstrikes on North Vietnam.

Meanwhile, Royal Thai air force planes and Royal Laotian planes based in Thailand were flying bombing missions over territory held by the Pathet Lao in both Laos and Thailand. On the ground, Thai and Laotian special forces units, ferried by Air America from Thailand to Laos, attacked Pathet Lao positions.

In early 1966, Thailand openly pledged to send combat troops to Vietnam (in addition to the Thai soldiers already placed into Laos for covert operations). Within months of the announcement, 5,000 men had volunteered. In 1969 the Thai military deployed more than 12,000 ground troops, including the Queen’s Cobras regiment and the Black Panther Division of the Royal Army Volunteer Force. 

By 1971, 15 percent of the Thai army was in South Vietnam, perhaps as many as 22,000 troops, not including those in covert actions. Their primary mission was to fight North Vietnamese guerrilla forces taking refuge in Laos. The U.S. Air Force’s 606th Air Commando Squadron trained Thai forces in counterinsurgency operations. And the Thai air force was deployed to support the ground forces.

Three Thai special forces units joined with the U.S. 1st Special Forces Group, and by early May 1966 the joint forces began conducting 30-day missions into remote, undisclosed locations not just inside Laos, but throughout Indochina.

Thai forces were very effective in their missions, and thus Thailand became the target of ever-increasing guerrilla attacks. In 1967, guerrillas killed 138 people, including 78 government officials.

Udorn Royal Thai Air Base was hit by a guerrilla attack in July 1968. Several aircraft were lost, and five American and Thai personnel were injured. Four of the intruders were killed, among them a North Vietnamese Army officer.

After the attacks on the air base, Thai counterinsurgency and covert missions increased. In July 1968 three groups of Thai special forces were sent into Laos to conduct long-range reconnaissance missions. An estimated 21,000 Thais were operating in Laos by 1973. They often dressed like and lived with the ethnic Lao and Hmong populations.

In addition to combating Pathet Lao infiltrations, the Thais had to contend with the Viet Cong, Muslim separatists, Chinese terrorists and even Indonesian communists. All of those groups were a constant threat to the stability of Thailand’s government, either through terrorist-style attacks or direct confrontation along the border. The rather large Vietnamese population also was still a great concern.

The CIA reported that “all conditions for rapid development of a subversive mechanism were present in Thailand.” CIA intelligence pointed out that the Chinese were actively working with the Pathet Lao and possibly with the Muslim insurgency in southern Thailand and Malaysia.

With Thailand facing threats on all fronts, the U.S. increased the military and economic aid being sent. Like South Vietnam, Thailand was becoming increasingly dependent upon U.S. support.

Gen. William Westmoreland, the top U.S. commander in South Vietnam, awards a Thai soldier in 1968. (U.S. Army)

Despite the valuable assistance the Thai government had provided to the U.S., by August 1970 President Richard Nixon didn’t consider Thailand as important as his predecessors did. Realizing this, the Thai government decided to halt its clandestine operations in Laos and asked the United States to remove American forces from Thailand.

While the request did have merit and the forces were removed over time, Thailand’s actions were more an act of political showmanship than anything else. Even though 48,000 U.S. troops were eventually removed from Thailand, covert operations continued, albeit to a lesser extent, until 1975.

Despite the departure of the American military, Thailand never fell under communist control like its neighbors to the east did. Indeed, Thailand emerged as one of the region’s strongest and most stable economies. American troop withdrawal did not mean that American financial aid stopped, as happened in South Vietnam, and that may be one of the reasons Thailand was able to hold on when others could not.

Dana Benner holds a bachelor’s degree in U.S. history and Native American culture and a master of education degree in heritage studies. He teaches history, political science and sociology on the university level. Benner served more than 10 years in the U.S. Army.

 This feature originally appeared in the April 2020 issue of Vietnam magazine. To subscribe, click here.