In 1963, South Vietnamese President Ngo Dinh Diem and his brother Ngo Dinh Nhu were killed in a military coup.

CNN: Saturday,

In 1955, Ngo Dinh Diem proclaimed South Vietnam a republic and declared himself president.

CNN: Sunday,

Kennedy to approve a coup that left our client in South Vietnam, Ngo Dinh Diem, with a bullet in the back of his head?

WSJ: Eliot A. Cohen: A Wartime President