Answer: Because of his heavy-handed tactics and brutal treatments
Step-by-step explanation:
The United States of America killed the leader of South Vietnam in the 1960s and he was called Ngo Dinh Diem. He was having heavy-handed tactics against the Viet Cong insurgency. He had brutal treatment of the opposition to his regime, and nobody did think that his treatments very good. He was killed during a coup d'etat. The ones that killed him very his generals in 1963.