This article analyzes what the drivers of contestation of secondary powers vis-à-vis the regional power are, differentiating therein between structural, historical, behavioural and domestic such drivers. We argue that in regions characterized by relative stability where major interstate violent conflicts are unlikely, as is the case in South America, secondary powers rely mainly on soft-balancing mechanisms vis-à-vis the regional power. Whereas Brazil's foreign policy behaviour is key to South American secondary powers being induced to contest the country's powerhood, the choices that the foreign policy elites of those secondary powers make regarding what the specific expression of soft balancing is to be are influenced by certain domestic groups. Empirical examples are given of how Argentina, Chile, Colombia and Venezuela as secondary powers unfold these domestic drivers, which shape their different ways of soft balancing Brazil. The article thus explains why some secondary powers rely more on institutional binding, others on economic statecraft, or buffering, while others contest by offering and building alternative leadership proposals.