Nguyễn Cao Kỳ becomes Prime Minister of South Vietnam at the head of a military junta; General Nguyễn Văn Thiệu becomes the figurehead chief of state.

Nguyễn Cao Kỳ was a South Vietnamese military officer and politician who served as the chief of the Republic of Vietnam Air Force in the 1960s, before leading the nation as the prime minister of South Vietnam in a military junta from 1965 to 1967. Then, until his retirement from politics in 1971, he served as vice president to bitter rival General Nguyễn Văn Thiệu, in a nominally civilian administration.

South Vietnam, officially the Republic of Vietnam, was a country in Southeast Asia that existed from 1955 to 1975. It first garnered international recognition in 1949 as the associated State of Vietnam within the French Union, with its capital at Saigon. Since 1950, it was a member of the Western Bloc during the Cold War. Following the 1954 partition of Vietnam, it became known as South Vietnam and was established as a republic in 1955. South Vietnam was bordered by North Vietnam to the north, Laos to the northwest, Cambodia to the southwest, and Thailand across the Gulf of Thailand to the southwest. Its sovereignty was recognized by the United States and 87 other nations, though it failed to gain admission into the United Nations as a result of a Soviet veto in 1957. It was succeeded by the Republic of South Vietnam in 1975. In 1976, the Republic of South Vietnam and North Vietnam merged to form the Socialist Republic of Vietnam.

Nguyễn Văn Thiệu was a South Vietnamese military officer and politician who was the president of South Vietnam from 1967 to 1975. He was a general in the Republic of Vietnam Armed Forces (RVNAF), became head of a military junta in 1965, and then president after winning a rigged election in 1967. 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.