Titoist Yugoslavia—the multiethnic state rising out of the chaos of World War II—is a particularly interesting setting to examine the integrity of the modern nation-state and, more specifically, the viability of a distinctly multi-ethnic nation-building project. Much scholarly literature has been devoted to the brutal civil wars that destroyed Yugoslavia during the 1990s with emphasizes on divisive nationalism and dysfunctional politics. But what held Tito's state together for the preceding forty-six years? In an attempt to understand better what united the stable, multiethnic, and successful Yugoslavia that existed before 1991, this dissertation illuminates the pervasive problem of legitimacy within this larger history. Cast aside and threatened with removal by Stalin's henchmen after the war, Tito made his revolution a genuine alternative to Soviet control. Because Tito and the ruling elite feared the loss of political power by either foreign aggression or from domestic groups challenging the Communist Party's (LCY) claim to govern, they fought hard for the reform of Marxism. Furthermore, Yugoslav elites manipulated popular conceptions of a Yugoslav identity as a means to solidify their regime with a unifying and progressive identity. Citing elite perceptions of the Yugoslav system—including key aspects of central institutions such as the LCY and the military— this dissertation attempts to reconcile how leaders of a country that scholars have dismissed as full of national hatreds had constructed a functioning and popular system for so long.