Udenism doesn’t finish in UDN. It isn’t just a party ideology, but an ensemble of political practices and beliefs, who has strongly determined a certain party acts and ideas, but not just that. Only referring to UDN this amount of practices and ideas becomes a define ideology, nevertheless their consequences certainly surpass it. In fact, it’s an ideology trespass by profound ambiguities, bigger than the traditional division between theory and practice. Beyond the conjunction between authoritarian practices and liberal discourse, udenist’s actors reveal conflicts in their acts’ core, and contradictory theoretical beliefs. This work looks for some reasons of those conflicts, based at udenism insertion in Brazilian political thought tradition. Determined by different influences, udenism reveals itself as an ideology divided, who utilizes its great opponent arguments, Vargas’s instrumental authoritharism, as its main political practice. Ambiguity isn’t only accidental, it defines the udenism’s core. This work aims to define not only the authoritarian concept’s use, identified with a certain first Republic tradition, but also to investigate such practices’ motives and consequences, vital task for a adequate view of Brazilian’s politics between 1946-1964.