Ngo Dinh Diem was a catholic from Central Vietnam. At a young age he worked for the French colonial administration as a province governor and in 1933 became Bao Dai's Minister of Interior. He left Vietnam in 1950, living in the United States and Belgium until 1954, when Bao Dai appointed him as his Prime Minister. A year later, Diem doctored a referendum, with American support, and ousted the Emperor.

Diem stayed in power until 1963, when he was deposed and assassinated in a coup led by General Minh. The high level of corruption of his regime and its lack of popular support made U.S. support for him one of the main controversies of U.S. policy towards Vietnam.

Letter from Eisenhower to Diem
From the Vietnam Wars Page at Vassar College
http://vietnam.vassar.edu/~vietnam/doc5.html

Eisenhower promises Diem direct assistance to the government in exchange for reforms.

Letter from Diem to Kennedy
From Tom Dier's Vietnam Page
http://greene.xtn.net/~wingman/docs/lettdiem.htm

Ngo Dinh Diem sent this letter to President Kennedy in December 1961, requesting U.S. support in the fight against the North. Aware of U.S. fears of a global Communist takeover, Diem reminds Kennedy in his letter that the war in Vietnam is another episode of the larger confrontation of Communism vs. Free World.

Kennedy's response to Diem
From Tom Dier's Vietnam Page
http://greene.xtn.net/~wingman/docs/letdiem2.htm

Kennedy's December 14, 1961, response to Diem, promising an increase of U.S. assistance for South Vietnam.

Excerpts from Law 10/59 against suspected communists
From the Vietnam Wars Page at Vassar College
http://vietnam.vassar.edu/~vietnam/doc6.html

This law was representative of the harsh repression of Diem's regime, which led to unrest and, eventually, the coup that unseated him.

Phone Conversation Between Ngo Dinh Diem and Henry Cabot Lodge, November 1, 1963
From the Vietnam Wars Page at Vassar College
http://vietnam.vassar.edu/~vietnam/doc8.html

Under instructions of "not thwarting" General Minh's coup, Lodge coldly responds to Diem's call for help. While offering U.S. assistance to ensure Diem's personal safety, Lodge refuses to offer any support for the survival of the regime. Diem and his brother Ngo Dinh Nhu were assassinated shortly after.