 The referendum was widely condemned for being fraudulent . Historian and writer Jessica Chapman said " Even Diệm apologists like Anthony Trawick Bouscaren and American CIA officer Edward Lansdale concur with the prime minister 's harshest critics on the conclusion that the South Vietnamese government was either incapable of or unwilling to hold a truly free , representative plebiscite " . A CIA report written in 1966 adjudged the poll to be the most heavily manipulated in the first 11 years of South Vietnam 's history . The U.S. government privately concluded that the monopoly Diệm had on the media and the election campaign was a greater factor in the victory than intimidation and the fact that the voting was effectively public . Reinhardt cabled Washington , saying that the " referendum proved [ a ] resounding success for [ the ] Diem government " . He indicated that the poll results were not necessarily a reflection of reality by adding that the result did not show that Diệm had majority support but that he was able to control the country , effectively unchallenged . The U.S. government was heartened by Diệm 's apparent ability to negate communist and other opposition . 
