Competence Expansion and Legitimization in the European Court of Justice

authority? The separation-of-powers literature has traditionally argued that a split legislator increases courts’ autonomy, as it faces no credible threat of a legislative override. However, many courts – and in particular international courts – rely on a coordinated action from policy-makers to ensure implementation. To the extent that courts care about their effectiveness, we may therefore expect that political division in fact induces self-restraint. Courts further rely on their reputation as useful venues for even-handed problem-solving. This legitimacy rests on a belief that courts are apolitical. When courts resolve questions subject to political debate, they appear as political actors themselves. As polarization among policy makers increases, the court’s decision politicizes. We define politicized questions as touching upon salient issues that affect a larger number of actors and that have a polarizing effect. We argue that courts react to a politicized context by a) seeking to convince policy-makers that the judicial process includes all the checks and balances of a representative body and b) by refraining from further affirmation of its authority. This paper relies on original data on all cases brought before the Court of Justice of the European Union (CJEU) relating to the “Free movement of people” (1954-2015). The CJEU is arguably the world’s most powerful international court and is often portrayed as driving European integration in the face of governments’ incapacity to coordinate. We demonstrate on the one hand that, as the polarization of EU integration grows among member states, the Court increasingly relies on larger chamber formations in an attempt to legitimize its position. On the other hand, we show that the same polarization reduces the likelihood that the Court affirms its authority. Thus, the Court’s use of direct effect and doctrinal innovations are more frequent in periods where there is consensus among policy makers.