The aim of the article is to clarify the nature and function of the augural formal defect known as uitium, by attempting to reassess the declarations of uitium by the augural college in the context of the patricio-plebeian conflict of the 5th-4th centuries, the Second Samnite War, and the Second Punic War, as well as the augural formal defects resulting from the announcement of unfavourable signs (obnuntiatio), mainly documented towards the end of the Republic. Drawing on Jörg Rüpke’s suggestions on obnuntiatio, it is proposed that the augural uitium should be equated with a rupture in internal political negotiations within the senatorial aristocracy – a rupture that is legitimate because it is carried out in the name of the gods and in deference to institutions.