On 2 November 1963, Ngô Đình Diệm, the president of South Vietnam, was arrested and assassinated in a CIA-backed coup d'état led by General Dương Văn Minh.

When rebel forces entered the palace, Diệm and his adviser and younger brother Ngô Đình Nhu were not present, having escaped to a loyalist shelter in Cholon.

Opposition candidates were threatened with being charged for conspiring with the Viet Cong, which carried the death penalty, and in many areas, large numbers of ARVN troops were sent to stuff ballot boxes.

Public servants and army officers had long been promoted on the basis of religious preference, and government contracts, US economic assistance, business favors and tax concessions were preferentially given to Catholics.

The key turning point came shortly after midnight on 21 August, when Nhu's Special Forces raided and vandalised Buddhist pagodas across the country, arresting thousands of monks and causing a death toll estimated to be in the hundreds.

Unknown to Diệm, General Đính, the supposed loyalist who commanded the ARVN III Corps that surrounded the Saigon area, had allied himself with the plotters of the coup.

The transfer allowed the rebels to completely encircle the capital and denied Cao the opportunity of storming Saigon and protecting Diệm, as he had done during the previous coup attempt in 1960.

Minh and Đôn had invited senior Saigon based officers to a meeting at the headquarters of the Joint General Staff (JGS), on the pretext of routine business.

Assistant Secretary of State Roger Hilsman had written in August that "under no circumstances should the Ngô brothers be permitted to remain in Southeast Asia in close proximity to Vietnam because of the plots they will mount to try to regain power.

[13] In contrast, a US Senate investigative commission in the early 1970s raised a provocative thought: "One wonders what became of the US military aircraft that had been dispatched to stand by for Lodge's departure, scheduled for the previous day.

"[13] The historian Mark Moyar suspected that Lodge could have flown Diệm to Clark Air Force Base in the Philippines, which was under American jurisdiction, before taking him to the final destination.

[19] Minh had also dispatched an M113 armored personnel carrier and four jeeps to Gia Long Palace to transport an arrested Diệm and Nhu back to JGS headquarters for official surrender.

While Minh was on the way to supervise the takeover of the palace, Generals Đôn, Trần Thiện Khiêm and Lê Văn Kim prepared the army headquarters for Diệm's arrival and a ceremonial handover of power to the junta.

A large table covered with green felt was brought in with the intention of seating Diệm for the handover to Minh and Vice President Nguyễn Ngọc Thơ, who was to become the civilian Prime Minister.

They escaped through one of the tunnels with two loyalists: Air Force Lieutenant Ðỗ Thơ, Diệm's aide-de-camp, who happened to be a nephew of Colonel Đỗ Mậu, the director of military security and a participant in the coup plot, and Xuân Vy, head of Nhu's Republican Youth.

The brothers sought asylum from the embassy of the Republic of China, but were turned down and stayed in Ma Tuyen's house as they appealed to ARVN loyalists and attempted to negotiate with the coup leaders.

[19] Nhu's secret agents had fitted the home with a direct phone line to the palace, so the insurgent generals believed that the brothers were still besieged inside Gia Long.

[19] After Minh had ordered the rebels to search the areas known to have been frequented by the Ngô family, Colonel Phạm Ngọc Thảo was informed by a captured Presidential Guard officer that the brothers had escaped through the tunnels to a refuge in Cholon.

[25] Lieutenant Thơ, who had earlier urged Diệm to surrender, saying that he was sure that his uncle Đỗ Mậu, along with Đính and Khiêm, would guarantee their safety, wrote in his diary later "I consider myself responsible for having led them to their death".

An investigation by Đôn determined that Nghĩa had shot the brothers at point-blank range with a semi-automatic firearm and that Nhung sprayed them with bullets before repeatedly stabbing the bodies with a knife.

"[28] Kennedy learned of the deaths on the following morning when National Security Council staffer Michael Forrestal rushed into the cabinet room with a telegram reporting the Ngô brothers' alleged suicides.

Kennedy later penned a memo, lamenting that the assassination was "particularly abhorrent" and blaming himself for approving Cable 243,[28] which had authorised Lodge to explore coup options in the wake of Nhu's attacks on the Buddhist pagodas.

He reasoned the devoutly Catholic Ngô brothers would not have taken their own lives, but Roger Hilsman rationalised the possibility of suicide by asserting that Diệm and Nhu would have interpreted the coup as Armageddon.

[31] Father Leger of Saint Francis Xavier Catholic Church asserted that the Ngô brothers were kneeling inside the building when soldiers burst in, took them outside and into the APC.

Embassy official Rufus Phillips, who was the US adviser to Nhu's Strategic Hamlet Program, said that "I wanted to sit down and cry",[33] citing the killings as a key factor in the future leadership troubles which beset South Vietnam.

[33] According to historian Howard Jones, the fact "that the killings failed to make the brothers into martyrs constituted a vivid testimonial to the depth of popular hatred they had aroused.

"[33] The assassinations caused a split within the coup leadership, turning the initial harmony among the generals into discord, and further abroad repulsed American and world opinion, exploding the myth that this new regime would constitute a distinct improvement over their predecessors, and ultimately convinced Washington that even though the leaders' names had changed in Saigon, the situation remained the same.

According to Jones, "when decisions regarding postcoup affairs took priority, resentment over the killings meshed with the visceral competition over government posts to disassemble the new regime before it fully took form.

"[35] Trần Văn Hương, a civilian opposition politician who was jailed in 1960 for signing the Caravelle Manifesto that criticised Diệm, and later briefly served as Prime Minister, gave a scathing analysis of the generals' action.

According to the eulogy, Diệm died because he had resisted the domination of foreigners and their plans to bring great numbers of troops to Vietnam and widen a war which would have destroyed the country.