When viewed from a personnel perspective, the Council of the European Union is the world’s most dynamic legislative chamber. The national ministers who sit at the apex of the Council system come and go with greater frequency than the politicians who populate national legislative chambers. These high levels of turnover have important effects on the distribution of power in the EU system. They endanger the Council’s cohesion and weaken it vis-à-vis the European Commission and the European Parliament (Scherpereel and Perez 2015). High turnover rates also empower nominally subordinate levels of the Council system (Perez and Scherpereel 2016). These insights suggest that Council dynamics resemble those of more conventional (national and subnational) legislatures: turnover threatens institutional cohesion and empowers actors both “beyond” and “below” an institution’s high office holders (Carey, Niemi, and Powell 2000; Matland and Studlar 2004; Niemi and Winsky 1987; Polsby 1993; Rosenthal 1992). In this paper, we attempt to deepen emerging insights about the effects of personnel flux on the EU system and the effects of parties on public policy (Guinaudeau 2014; Leinaweaver and Thomson 2016; Schmidt 1996). We do so by considering the partisan dimension of ministerial turnover. We begin by distinguishing between interpartisan replacement and intrapartisan replacement. Interpartisan replacement takes place when an old minister is replaced by a new minister from a different political party. Intrapartisan replacement takes place when an old minister is replaced by a new minister from the same political party. We then seek to determine the extent to which these different kinds of replacement affect (a) the success of particular governments in Council negotiations, (b) the relationship between the Council and the EU’s other institutions, and (c) the vertical distribution of authority within the Council. We seek, in other words, to investigate the extent to which interpartisan and intrapartisan replacements affect horizontal intrainstitutional, horizontal interinstitutional, and vertical intrainstitutional balances of power. We argue that interpartisan replacements have particularly important effects. With regard to power balances within the Council, we suggest that countries experiencing interpartisan replacements perform less well in negotiations than countries that experience personnel consistency or intrapartisan replacement. With regard to relations among the institutions, we suggest that Council configurations that experience high levels of interpartisan replacement are more likely to lose ground to the Commission and the Parliament. And with regard to vertical relations within the Council, we suggest that ministers in configurations that experience high levels of interpartisan replacement tend to concentrate more decision-making discretion in ministers’ hands.
