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

In a telegram to the American Embassy in Saigon, U.S. Assistant Secretary of State Roger Hilsman says that at some point, were the US to require "political liquidation" in South Vietnam, it should also "urgently examine all possible alternative leadership and make detailed plans as to how we might bring about Diem's replacement if this should become necessary".

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

According to the historian Ellen Hammer, there were "perhaps as many as six and possibly more" different plots,[23] and these spanned the gamut of society to include civilian politicians, union leaders, and university students.

[25][26] Another person in this group was Colonel Phạm Ngọc Thảo, an undetected communist agent who was deliberately fomenting infighting among the officers and mismanaging the Strategic Hamlet Program in order to destabilise the Saigon government.

[30] Thảo's 24 October coup was canceled after senior officers decided that their younger colleagues could not succeed without the help of General Tôn Thất Đính, a loyalist who controlled the III Corps.

[44][51] In the heady times after the attacks, Đính told his American advisors that "he was without doubt the greatest general officer in the ARVN, the saviour of Saigon ... and soon he would be the top military man in the country".

[45][55] The other generals told him that the people were dissatisfied with Diệm's cabinet and that Vietnam needed dynamic young officers in politics, and that their presence would reverse the declining morale in the ARVN.

The loyalists and some of Nhu's underworld connections were also to kill some figures who were assisting the conspirators, such as the titular but relatively powerless Vice President Nguyễn Ngọc Thơ, CIA agent Lucien Conein, who was on assignment in South Vietnam as a military adviser, and Lodge.

Three marine battalions in tanks and armored cars had moved toward the Saigon city center to spearhead the revolt, and some of the 7th Division had arrived from the Mekong Delta to cut the main road from the south into Tân Sơn Nhứt Air Base.

Khiêm reported this to Đôn, and claimed that he had placed Chinese medicinal oil into his eyes to irritate and redden them and thus give the appearance he had become remorseful about the coup, in order to test Đính's loyalty to the plot.

[78] On 1 November, the plotters summoned many senior officers who were not involved in the plot to the JGS headquarters at Tân Sơn Nhứt, on the pretext of a routine lunchtime leadership meeting.

[95] The latter installation was captured by some newly enlisted troops from the Quang Trung National Training Center, led by General Mai Hữu Xuân,[1] who promptly arrested the Diem supporters in the office.

The Australian historian Anne E. Blair said "there can be no doubt that Lodge silenced some of Diệm's rejoinder, supremely confident as he was in his ability to control not only the American press but the official government records as well".

At the same time, the US military ordered units of the Seventh Fleet to move into the waters near Saigon as a "precautionary measure" in case the fighting endangered Americans lives and to deter an opportunistic communist offensive.

For security reasons, the surrounding streets were regularly sealed after sunset; the building had several bunkers and an intricate tunnel system, including a half-block-long escape route to the basement of the City Hall.

[105] When I Corps commander General Đỗ Cao Trí was informed that coup was imminent, he left Huế on 29 October for Đà Nẵng so that he would be away from Ngô Đình Cẩn, who ruled central Vietnam from Hue for his family.

In contrast, a United States Senate investigative commission in the early 1970s raised a provocative conundrum: "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.

Minh had also dispatched an APC and four jeeps to Gia Long to transport Diệm and Nhu back to JGS headquarters for the ceremonial handover of power during a nationally televised event witnessed by international media.

[114] Hammer asserts that they walked past the tennis courts and left the palace grounds through a small gate at Le Thanh Ton Street and entered the car.

[41] 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.

[41] 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.

An investigation by Đôn later determined that Nghia 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.

Kennedy later penned a memo, lamenting that the assassination was "particularly abhorrent" and blaming himself for approving Cable 243,[121] which authorised Lodge to explore coup options in the wake of Nhu's Xá Lợi Pagoda raids.

Several members of the Kennedy administration were appalled by the killings, citing them as a key factor in the future leadership troubles which beset South Vietnam.

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.

"[133][134] On the night of 1 November, as Gia Long Palace was besieged, VC radio in South Vietnam had urged the Vietnamese people and ARVN loyalists to resist the coup.

As Lodge traveled from his residence to the US embassy, the crowds cheered his convoy, and when he walked past the Xá Lợi Pagoda, the focal point of the raids by Nhu's Special Forces, he was mobbed by jubilant Buddhists.

[137] Further, it condemned the recent legislative elections as "dishonest and fraudulent", imposed martial law, announced a curfew, and ordered the release of political prisoners jailed by Diệm.

[105][142] The generals decided on a two-tier government structure, with a military committee overseen by Minh presiding over a regular cabinet that would be predominantly civilian, with Thơ as prime minister.