He established rule over South Vietnam until he resigned and left the nation and relocated to Taipei a few days before the fall of Saigon and the ultimate North Vietnamese victory.

In 1967, a transition to elected government was scheduled; and, after a power struggle within the military, Thiệu ran for the presidency with Kỳ as his running mate—both men had wanted the top job.

[4] During the 1971 Operation Lam Sơn 719 and the communists' Easter Offensive, the I Corps in the north of the country was under the command of his confidant, Hoàng Xuân Lãm, whose incompetence led to heavy defeats until Thiệu finally replaced him with Ngô Quang Trưởng.

[5][6] Born in Phan Rang on the south central coast of Vietnam, Thiệu was a son of a small, well-off landowner who earned his living by farming and fishing.

[8] With the help of his brother, Nguyễn Văn Hiếu, a Paris-trained lawyer who served in the upper echelons of the State of Vietnam government, Thiệu initially was enrolled in the Merchant Marine Academy.

[9] On 11 November 1960, Colonels Vương Văn Đông and Nguyễn Chánh Thi launched a coup attempt against President Ngô Đình Diệm, but after surrounding the palace, they stopped attacking and decided to negotiate a power-sharing agreement.

In 1971, Minh claimed that Thiệu had caused the deaths by hesitating and delaying the attack on Gia Long Palace, implying that if Diệm was captured there, junior officers could not have killed him while in a small group.

[25] In August 1964, the current junta head, General Nguyễn Khánh, who had in fact deposed Minh and his colleagues in January or at least heavily weakened him – as he had to formally retain Minh in recognition of the United States' will – decided to increase his authority by declaring a state of emergency, increasing police powers, banning protests, tightening censorship and allowing the police arbitrary search and imprisonment powers.

However, these moves served only to weaken Khánh as large demonstrations and riots broke out in the cities, with majority Buddhists prominent, calling for an end to the state of emergency and the abandonment of the new constitution, as well as a progression back to civilian rule.

[26] Fearing that he could be toppled by the intensifying protests, Khánh made concessions,[28] repealing the new constitution and police measures, and promising to reinstate civilian rule and remove the Cần Lao, a Catholic political apparatus covertly used to maintain the Diệm regime in power by seeking out dissenters, etc.

[38] The signature of Chief of State Phan Khắc Sửu was required to pass the ruling, but he referred the matter to the High National Council (HNC), an appointed civilian advisory body, to get their opinion.

[38] This prompted US Ambassador Maxwell D. Taylor to angrily berate Thiệu, Thi, Kỳ and Cang in a private meeting and threaten to cut off aid if they did not reverse their decision.

[41] Thiệu was again plotting the following month when the junta-appointed Prime Minister, Trần Văn Hương, introduced a series of war expansion measures, notably by widening the terms of conscription.

[48] Thiệu took a cautious approach, as did Có and Cang, and they were pre-empted by Colonel Phạm Ngọc Thảo, an undetected communist double agent, who launched a coup with Phát on a hardline Catholic platform without US backing.

[50][51][52] There were claims that Thiệu ordered the military to capture and extrajudicially kill Colonel Phạm Ngọc Thảo, who died in 1965 after a series of coup attempts between various ARVN officers.

[63] On 1 February, Thiệu declared martial law,[64] and in June, the National Assembly approved his request for a general mobilization of the population and the induction of 200,000 draftees into the armed forces by the end of the year;[64] the bill had been blocked before the Tết Offensive.

[72] In late 1973, the communists issued Resolution 21, which called for "strategic raids" against South Vietnam to gain territory and to gauge the reaction of Thiệu and the American government.

[77] Thiệu believed the American promise to reintroduce air power against the communists if they made any serious violations of the agreement,[77] and he and his government also assumed that US aid would continue to be forthcoming at previous levels.

[78][80] Despite Nixon's growing political difficulties and an increasingly hostile working relationship with the legislature over Vietnam,[81] Thiệu, and most of the Saigon leadership, remained optimistic about ongoing aid.

[96][97] Due to Thiệu's insistence on not surrendering any territory, the army was spread very thinly, defending useless terrain along a 600 mile (966 km) frontier, while the strategic reserve was occupied in static defensive roles.

[102] On 2 January 1975, Thiệu held an emergency meeting with General Dư Quốc Đống, who was in charge of the Phước Long situation, and other senior military figures.

[104] Thiệu decided to cede the entire province to the North Vietnamese, since it was considered to be less important than Tây Ninh, Pleiku, or Huế — economically, politically, and demographically.

[118] After reviewing the situation, Thiệu pulled out a small-scale map of South Vietnam and discussed the possible redeployment of the armed forces to "hold and defend only those populous and flourishing areas which were really most important".

"[124][125] With respect to the I and II Corps Zones, he drew a series of phase lines on the map indicating that South Vietnamese forces should hold what they could,[125] but that they could redeploy southward if needed.

Thiệu had decided to abandon Pleiku and Kon Tum so that the II Corps forces could concentrate on retaking Buôn Ma Thuột, which he considered more important.

[129][130] Phú then decided that the only possible means of doing this was to retreat to the coast along Interprovincial Route 7B, a dilapidated, rough track with several downed bridges, before recuperating and counterattacking back into the highlands.

[158][161] As anarchy and looting enveloped Đà Nẵng, with a defense of the city becoming impossible, Trưởng requested permission to evacuate by sea, but Thiệu, baffled, refused to make a decision.

[175][176] General Dũng prepared a three-pronged attack, which would seize the vital highway intersection at Xuân Lộc,[177] the capital of Long Khánh Province and "the gateway to Saigon",[178] before heading for Biên Hòa.

"[199] The military historian Lewis Sorley suggests that Thiệu "was arguably a more honest and decent man than Lyndon Johnson, and – given the differences in their respective circumstances – quite likely a more effective president of his country.

[200] He died on 29 September 2001, aged 78, at Beth Israel Deaconess Medical Center in Boston, after he collapsed and was put on a respirator due to a stroke which he suffered at his Foxborough home.