Who are more powerful in a federation, national or subnational politicians? As the cases of democratic Brazil, Spain and South Africa show, there is no straightforward answer to this question. As the power of politicians in a federation can be periodically changed, in democratizing federations such as Brazil (1988-2002), Spain (1979-2004), and South Africa (1994-2007) subnational politicians have been constantly bargaining to increase their autonomy vis-à-vis national politicians through a process of federalization and decentralization. In the light of these processes, I explain how and why the locus of authority has changed after a democratic constitutional pact has been reached between national and subnational political elites in the three cases. In the comparison, I observe that in democratizing countries where decentralization and federalization (independent variable) unfold under a bargained interaction between levels of government, the subnational political actors can gain institutional and policy autonomy (dependent variable) to shift the balance of power to the subnational levels (e.g. municipalities and states/provinces). In building a causal chain of events that explains changes in the intergovernmental balance of power, I show how and why decentralization-cumfederalization leads to de facto subnational autonomy in Brazil, Spain and South Africa. This research suggests that when changes in the intergovernmental dynamics occurred in Brazil, Spain, and South Africa, they were mainly endogenously generated by a mechanism that has reinforced over time the prevailing interest of subnational political elites reached at the time of the all-encompassing constitutions. The research findings indicate that despite the variations in the strategies of intergovernmental actors to shift the intergovernmental balance of power, the subnational interests have prevailed most of the time through decentralization and federalization processes. In all three cases intergovernmental relations changed from a centralized to a more dispersed distribution of authority, and from an imposed form of cooperation to a more bargained one. In order to search for external validation, I compare the abovementioned findings against the experiences of three additional countries —India, Malaysia and Mexico. These countries have shown that, despite being federations, intergovernmental bargaining has been limited and the processes of decentralization and federalization have been undermined by national political elites. This case-oriented research accomplishes the following goals: theoretically, it proposes a model that explains change and shifts of intergovernmental balance of power across countries; and, empirically, it presents the conditions under which intergovernmental balance of power can be changed.