The U.S. conservative movement in the mid-20th Century argued that the United States needed to continuously get tougher in the fight against communism worldwide. It remained supportive of U.S. efforts throughout the Vietnam War. However, in the period immediately preceding Americanization of the war in 1965, conservatives were uncertain about the outcome of any fighting in Vietnam. Specifically, they claimed that optimism for the Republic of Vietnam was lost with the assassination of President Ngo Dinh Diem in 1963. Without Diem, conservatives claimed, the Vietnam War was likely lost before it began. This article discusses how Diem went from a barely talked-about anti-Communist ally prior to his death to becoming posthumously the last great hope for Southeast Asia. Conservatives argued that without Diem, the only way the United States would be able to stop Communist expansion in Indochina would be to engage in a massive aerial bombing campaign and find a regional partner to deploy troops. Had he survived, this might not have been necessary. Learning why and how conservatives supported Diem after his death helps us better understand how conservatives reacted to the Vietnam War once Americanization began in 1965.