when was ngo dinh diem assassinated?
1963
Ngo Dinh Diem
 He was the final prime minister of the State of Vietnam (1954–55), and then served as President of South Vietnam (Republic of Vietnam) from 1955 until he was deposed and assassinated during the 1963 military coup.

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Ngo Dinh Diem [SEP] Introduction
Diệm soon consolidated power in South Vietnam, aided by his brother Ngô Đình Nhu. After a rigged referendum in 1955, he proclaimed the creation of the Republic of Vietnam, with himself as president. His government was supported by other anti-communist countries, most notably the United States. Diệm pursued a series of nation-building schemes, emphasising industrial and rural development. From 1957, he was faced with a communist insurgency backed by North Vietnam, eventually formally organized under the banner of the Việt Cộng. He was subject to a number of assassination and coup attempts, and in 1962 established the Strategic Hamlet Program as the cornerstone of his counterinsurgency effort.