In 1955, Prime Minister Ngô Đình Diệm held a referendum to decide whether the State of Vietnam would remain a monarchy or become a republic. This referendum was blatantly rigged in favor of a republic. Not only did an implausible 98% vote in favor of deposing Bảo Đại, but over 380,000 more votes were cast than the total number of registered voters; in Saigon, for instance, Diệm was credited with 133% of the vote. Diệm proclaimed himself the president of the newly formed Republic of Vietnam. Despite successes in politics, economics and social change in the first 5 years, Diệm quickly became a dictatorial leader. With the support of the United States government and the CIA, ARVN officers led by General Dương Văn Minh staged a coup and killed him in 1963. The military held a brief interim military government until General Nguyễn Khánh deposed Minh in a January 1964 coup. Until late 1965, multiple coups and changes of government occurred, with some civilians being allowed to give a semblance of civil rule overseen by a military junta.