Are Judges on Per Curiam Courts Ideological? Evidence from the European Court of Justice

Abstract Institutional designers of judiciaries often want to provide the appearance of impartiality. As a result, many collegial courts issue per curiam rulings in which judges’ votes are not public. An extensive scholarship, however, provides evidence that ideology and mechanisms of retention affect judicial decision-making. Do per curiam rulings actively mitigate or provide cover for ideological and career-oriented judicial decision-making? I argue that – when serving as the rapporteur (opinion-writer) – a judge on a civil law per curiam court can steer their panel towards the outcome their appointer prefers. When their appointing government turns over, nonetheless, a judge is not compelled to change their decision-making to be in line with their new government, as per curiam rulings protect them from retaliation. An analysis of decisions at the Court of Justice of the European Union provides evidence for this account.