According to the Pentagon Papers, which commented on Eisenhower's observation, Diệm would have been a more popular candidate than Bảo Đại against Hồ, stating that "It is almost certain that by 1956 the proportion which might have voted for Ho - in a free election against Diem - would have been much smaller than 80%."[96] In 1957, independent observers from India, Poland, and Canada representing the International Control Commission (ICC) stated that fair elections were impossible, with the ICC reporting that neither South nor North Vietnam had honored the armistice agreement.[97]

From April to June 1955, Diệm eliminated political opposition in the south by launching operations against religious groups: the Cao Đài and Hòa Hảo of Ba Cụt. The campaign also attacked the Bình Xuyên organized crime group, which was allied with members of the communist party secret police and had military elements. The group was defeated in April following a battle in Saigon. As broad-based opposition to his harsh tactics mounted, Diệm increasingly sought to blame the communists.[8]

In a referendum on the future of the State of Vietnam in October 1955, Diệm rigged the poll supervised by his brother Ngô Đình Nhu and was credited with 98% of the vote, including 133% in Saigon. His American advisors had recommended a more "modest" winning margin of "60 to 70 percent." Diệm, however, viewed the election as a test of authority.[88]: 224  He declared South Vietnam to be an independent state under the name Republic of Vietnam (ROV), with him as president.[25] Likewise, Ho Chi Minh and other communists won at least 99% of the vote in North Vietnamese "elections".[89]: 193–194, 202–203, 215–217 

The domino theory, which argued that if a country fell to communism, all surrounding countries would follow, was first proposed by the Eisenhower administration.[76]: 19  John F. Kennedy, then a senator, said in a speech to the American Friends of Vietnam: "Burma, Thailand, India, Japan, the Philippines and obviously Laos and Cambodia are among those whose security would be threatened if the Red Tide of Communism overflowed into Vietnam."[98]

Diệm era, 1954–1963
Main articles: Ngo Dinh Diem and War in Vietnam (1954–1959)

Rule

A devout Catholic, Diệm was fervently anti-communist, nationalist, and socially conservative. Historian Luu Doan Huynh notes "Diệm represented narrow and extremist nationalism coupled with autocracy and nepotism."[76]: 200–201  Most Vietnamese were Buddhist, and alarmed by Diệm's actions, like his dedication of the country to the Virgin Mary.

On 11 April 1955,[99] Diệm launched the "Denounce the Communists" campaign, during which suspected communists and other anti-government elements were arrested, imprisoned, tortured, or executed. He instituted the death penalty in August 1956 against activity deemed communist.[51] The North Vietnamese government claimed that, by November 1957, over 65,000 individuals were imprisoned and 2,148 killed in the process.[100] According to Gabriel Kolko, 40,000 political prisoners had been jailed by the end of 1958.[57]: 89  In October 1956, Diệm launched a land reform program limiting the size of rice farms per owner. 1.8m acres of farm land became available for purchase by landless people. By 1960, the process had stalled because many of Diem's biggest supporters were large landowners.[101]: 14–16 

In May 1957, Diệm undertook a 10-day state visit to the US. President Eisenhower pledged his continued support, and a parade was held in Diệm's honor. But Secretary of State Dulles privately conceded Diệm had to be backed because they could find no better alternative.[88]: 230 

Insurgency in the South, 1954–1960
Main articles: Viet Cong and War in Vietnam (1959–1963)

Between 1954 and 1957, the Diệm government succeeded in preventing large-scale organized unrest in the countryside. In April 1957, insurgents launched an assassination campaign, referred to as "extermination of traitors".[102] 17 people were killed in the Châu Đốc massacre at a bar in July, and in September a district chief was killed with his family.[51] By early 1959, Diệm had come to regard the violence as an organized campaign and implemented Law 10/59, which made political violence punishable by death and property confiscation.[103] There had been division among former Viet Minh, whose main goal was to hold elections promised in the Geneva Accords, leading to "wildcat" activities separate from the other communists and anti-GVN activists. Douglas Pike estimated that insurgents carried out 2,000 abductions, and 1,700 assassinations of government officials, village chiefs, hospital workers and teachers from 1957 to 1960.[25]: 106 [51] Violence between insurgents and government forces increased drastically from 180 clashes in January 1960, to 545 clashes in September.[104]

In September 1960, COSVN, North Vietnam's southern headquarters, ordered a coordinated uprising in South Vietnam against the government and a third of the population was soon living in areas of communist control.[25]: 106–107  In December 1960, North Vietnam formally created the Viet Cong (VC) with the intent of uniting all anti-GVN insurgents, including non-communists. It was formed in Memot, Cambodia, and directed through COSVN.[77]: 55–58  The VC "placed heavy emphasis on the withdrawal of American advisors and influence, on land reform and liberalization of the GVN, on coalition government and the neutralization of Vietnam." The identities of the leaders of the organization were often kept secret.[51]

Support for the VC was driven by resentment of Diem's reversal of Viet Minh land reforms in the countryside. The Viet Minh had confiscated large private landholdings, reduced rents and debts, and leased communal lands, mostly to poorer peasants. Diem brought the landlords back, people who had been farming land for years had to return it to landlords and pay years of back rent. Marilyn B. Young wrote that "The divisions within villages reproduced those that had existed against the French: 75% support for the NLF, 20% trying to remain neutral and 5% firmly pro-government".[105]: 73 

North Vietnamese involvement
See also: North Vietnamese invasion of Laos and Ho Chi Minh trail

In March 1956, southern communist leader Lê Duẩn presented a plan to revive the insurgency entitled "The Road to the South" to the Politburo in Hanoi. However, as China and the Soviets opposed confrontation, his plan was rejected.[77]: 58  Despite this, the North Vietnamese leadership approved tentative measures to revive southern insurgency in December 1956.[50] Communist forces were under a single command structure set up in 1958.[106] In May 1958, North Vietnamese forces seized the transportation hub at Tchepone in Southern Laos near the demilitarized zone, between North and South Vietnam.[107]: 24 

The North Vietnamese Communist Party approved a "people's war" on the South at a session in January 1959,[25]: 119–120  and, in May, Group 559 was established to maintain and upgrade the Ho Chi Minh trail, at this time a six-month mountain trek through Laos. On 28 July, North Vietnamese and Pathet Lao forces invaded Laos, fighting the Royal Lao Army all along the border.[108]: 26  About 500 of the "regroupees" of 1954 were sent south on the trail during its first year of operation.[109] The first arms delivery via the trail was completed in August 1959.[110] In April 1960, North Vietnam imposed universal military conscription for men. About 40,000 communist soldiers infiltrated the south from 1961 to 1963.[77]: 76 

Kennedy's escalation, 1961–1963
Main articles: War in Vietnam (1959–1963) and Strategic Hamlet Program

In the 1960 U.S. presidential election, Senator John F. Kennedy defeated incumbent Vice President Richard Nixon. Although Eisenhower warned Kennedy about Laos and Vietnam, Europe and Latin America "loomed larger than Asia on his sights."[88]: 264 

The Kennedy administration remained committed to the Cold War foreign policy inherited from the Truman and Eisenhower administrations. In 1961, the US had 50,000 troops based in South Korea, and Kennedy faced four crisis situations: the failure of the Bay of Pigs Invasion he had approved in April,[111] settlement negotiations between the pro-Western government of Laos and the Pathet Lao communist movement in May,[88]: 265  construction of the Berlin Wall in August, and the Cuban Missile Crisis in October. Kennedy believed another failure to stop communist expansion would irreparably damage US credibility. He was determined to "draw a line in the sand" and prevent a communist victory in Vietnam. He told James Reston of The New York Times after the Vienna summit with Khrushchev, "Now we have a problem making our power credible and Vietnam looks like the place."[112][113]

Kennedy's policy toward South Vietnam assumed Diệm and his forces had to defeat the guerrillas on their own. He was against the deployment of American combat troops and observed "to introduce U.S. forces in large numbers there today, while it might have an initially favorable military impact, would almost certainly lead to adverse political and, in the long run, adverse military consequences."[114] The quality of the South Vietnamese military, however, remained poor. Poor leadership, corruption, and political promotions weakened the ARVN. The frequency of guerrilla attacks rose as the insurgency gathered steam. While Hanoi's support for the VC played a role, South Vietnamese governmental incompetence was at the core of the crisis.[76]: 369 

One major issue Kennedy raised was whether the Soviet space and missile programs had surpassed those of the US. Although Kennedy stressed long-range missile parity with the Soviets, he was interested in using special forces for counterinsurgency warfare in Third World countries threatened by communist insurgencies. Although they were intended for use behind front lines after a conventional Soviet invasion of Europe, Kennedy believed guerrilla tactics employed by special forces, such as the Green Berets, would be effective in a "brush fire" war in Vietnam.

Kennedy advisors Maxwell Taylor and Walt Rostow recommended US troops be sent to South Vietnam disguised as flood relief workers.[115] Kennedy rejected the idea but increased military assistance. In April 1962, John Kenneth Galbraith warned Kennedy of the "danger we shall replace the French as a colonial force in the area and bleed as the French did."[116] Eisenhower put 900 advisors in Vietnam, and by November 1963, Kennedy had put 16,000 military personnel there.[25]: 131 

The Strategic Hamlet Program was initiated in late 1961. This joint U.S.–South Vietnamese program attempted to resettle the rural population into fortified villages. It was implemented in early 1962 and involved some forced relocation and segregation of rural South Vietnamese, into new communities where the peasantry would be isolated from the VC. It was hoped these new communities would provide security for the peasants and strengthen the tie between them and the central government. However, by November 1963 the program had waned, and it ended in 1964.[8]: 1070  In July 1962, 14 nations, including China, South Vietnam, the Soviet Union, North Vietnam, and the US, signed an agreement promising to respect Laos' neutrality.

Ousting and assassination of Ngô Đình Diệm
Main article: Arrest and assassination of Ngô Đình Diệm
See also: United States in the Vietnam War, Krulak–Mendenhall mission, McNamara–Taylor mission, and 1963 South Vietnamese coup d'état

The inept performance of the ARVN was exemplified by failed actions such as the Battle of Ấp Bắc on 2 January 1963, in which the VC won a battle against a much larger and better-equipped South Vietnamese force, many of whose officers seemed reluctant even to engage in combat.[117]: 201–206  The ARVN lost 83 soldiers and 5 US helicopters, serving to ferry troops shot down by VC forces, while the VC lost only 18 soldiers. The ARVN forces were led by Diệm's most trusted general, Huỳnh Văn Cao. Cao was a Catholic, promoted due to religion and fidelity rather than skill, and his main job was to preserve his forces to stave off coups. Policymakers in Washington began to conclude Diệm was incapable of defeating the communists and might even make a deal with Ho Chi Minh. He seemed concerned only with fending off coups and had become paranoid after attempts in 1960 and 1962, which he partly attributed to US encouragement. As Robert F. Kennedy noted, "Diệm wouldn't make even the slightest concessions. He was difficult to reason with ..."[118] Historian James Gibson summed up the situation:

"Strategic hamlets had failed ... The South Vietnamese regime was incapable of winning the peasantry because of its class base among landlords. Indeed, there was no longer a 'regime' in the sense of a relatively stable political alliance and functioning bureaucracy. Instead, civil government and military operations had virtually ceased. The National Liberation Front had made great progress and was close to declaring provisional revolutionary governments in large areas."[119]

Discontent with Diệm's policies exploded in May 1963, following the Huế Phật Đản shootings of nine Buddhists protesting the ban on displaying the Buddhist flag on Vesak, Buddha's birthday. This resulted in mass protests—the Buddhist crisis—against discriminatory policies that gave privileges to Catholics over the Buddhist majority. Diệm's elder brother Ngô Đình Thục was the Archbishop of Huế and aggressively blurred the separation between church and state. Thuc's anniversary celebrations occurred shortly before Vesak had been bankrolled by the government, and Vatican flags were displayed prominently. There had been reports of Catholic paramilitaries demolishing Buddhist pagodas throughout Diệm's rule. Diệm refused to make concessions to the Buddhist majority or take responsibility for the deaths. On 21 August 1963, the ARVN Special Forces of Colonel Lê Quang Tung, loyal to Diệm's younger brother Ngô Đình Nhu, raided pagodas, causing widespread destruction and leaving a death toll into the hundreds.

US officials began discussing regime change during the middle of 1963. The United States Department of State wanted to encourage a coup, while the Pentagon favored Diệm. Chief among the proposed changes was removal of Diệm's younger brother Nhu, who controlled the secret police and special forces, and was seen as being behind the Buddhist repression and the architect of the Ngô family's rule. This proposal was conveyed to the US embassy in Saigon in Cable 243. The CIA contacted generals planning to remove Diệm, and told them the US would not oppose such a move, nor punish them by cutting off aid. Diệm was overthrown and then executed, along with his brother, on 2 November 1963. When Kennedy was informed, Maxwell Taylor remembered he "rushed from the room with a look of shock and dismay on his face."[88]: 326  Kennedy had not anticipated Diệm's murder. The U.S. ambassador Henry Cabot Lodge, invited the coup leaders to the embassy and congratulated them. Lodge informed Kennedy that "the prospects now are for a shorter war".[88]: 327  Kennedy wrote Lodge a letter congratulating him for "a fine job".[120]