Colonel Phạm Ngọc Thảo of the Army of the Republic of Vietnam, and a communist spy of the North Vietnamese Viet Minh, along with Generals Lâm Văn Phát and Trần Thiện Khiêm, all Catholics, attempt a coup against the military junta of the Buddhist Nguyễn Khánh.

Phạm Ngọc Thảo, also known as Albert Thảo, was a Vietnamese military officer and spy. He was a sleeper agent of the Việt Minh who infiltrated the Army of the Republic of Vietnam (ARVN) and also became a major provincial leader in South Vietnam. In 1962, he was made overseer of Ngô Đình Nhu's Strategic Hamlet Program in South Vietnam and deliberately forced it forward at an unsustainable speed, causing the production of poorly equipped and poorly defended villages and the growth of rural resentment toward the regime of President Ngô Đình Diệm, Nhu's elder brother. In light of the failed land reform efforts in North Vietnam, the Hanoi government welcomed Thao's efforts to undermine Diem.