Since the 1950s, the domestic politics of the Republic of Vietnam (RVN) has puzzled outside observers. To these external analysts, the American-backed regime seemed to be plagued by instability and factionalism for no apparent reason. Their bewilderment, however, has obscured a deep and complex history. In Disunion, Nu-Anh Tran shows how factional struggles in the Saigon-based republic reflected serious disagreements about political ideas at a...