Although Ngô Đình Diệm personally was respected for his nationalism , political stability and policies triggering rapid economic growth , he ran a nepotistic and authoritarian government . Elections were routinely rigged and Diệm favored of minority Roman Catholics on many issues , believing that Catholics were " more trustworthy " , more anti-communist and more impermeable to Viet Cong infiltration . His religious policies sparked protests from the Buddhist community after demonstrators were killed on Vesak , Buddha 's birthday , in 1963 when they were protesting a ban on the Buddhist flag . This incident sparked mass protests calling for religious equality . The most famous case was of Venerable Thích Quảng Đức , who burned himself to death to protest . The images of this event made worldwide headlines and brought extreme embarrassment for Diệm . The tension was not resolved , and on August 21 , the ARVN Special Forces loyal to his brother and chief adviser Ngô Đình Nhu and commanded by Lê Quang Tung raided Buddhist pagodas across the country , leaving a death toll estimated to range into the hundreds . In the United States , the Kennedy administration became worried that the problems of Diệm 's government were undermining the US 's anti-Communist effort in Southeast Asia , and of Diệm 's increasing resistance and non-cooperation with the American government . On November 1 , 1963 , with the planning and backing of the CIA and the Kennedy administration , South Vietnamese generals led by Dương Văn Minh engineered a coup d'état and overthrew Ngô Đình Diệm , killing both him and his brother Nhu . ( '' see also Ngô Đình Cẩn '' ) Between 1963 and 1965 , South Vietnam was extremely unstable as no government could keep power for long . There were more coups , often more than one every year . The Communist-run Viet Cong expanded their operation and scored some significant military victories during this period . In 1965 , US President Lyndon Johnson sent troops to South Vietnam to secure the country and started to bomb North Vietnam , assuming that if South Vietnam fell to the Communists , other countries in the Southeast Asia would follow , in accordance with the domino theory . Other US allies , such as Australia , New Zealand , South Korea , Thailand , the Philippines , and Taiwan also sent troops to South Vietnam . Although the American-led troops succeeded in containing the advance of Communist forces , the presence of foreign troops , the widespread bombing over all of Vietnam , and the social vices that mushroomed around US bases upset the sense of national pride among many Vietnamese , North and South , causing some to become sympathetic to North Vietnam and the Viet Cong . In 1965 , Air Marshal Nguyễn Cao Kỳ and General Nguyễn Văn Thiệu took power in a coup , and presided over a stable junta , and promised to hold elections under US pressure . In 1967 , South Vietnam managed to conduct a National Assembly and Presidential election with Lt. General Nguyễn Văn Thiệu being elected to the Presidency , bringing the government to some level of stability
raided Buddhist pagodas across the country
Xá Lợi Pagoda raids
History of Vietnam since 1945