Courts Under Pressure: Career Incentives and Political Capture from Within

How do political elites shape the composition of high courts in systems formally designed to insulate judges from politics? This paper develops a model of judicial politicization in bureaucratic judiciaries, where career advancement to the highest courts is formally meritocratic but in practice responsive to political incentives. We argue that judges engage in early-career political signaling—such as running for internal judicial elections under ideologically aligned associations—to improve their chances of promotion when partisan gatekeepers are in control. We formalize this logic in a two-stage model in which judges first decide whether to expose their ideological leanings through intra-judicial elections, and then political actors select high court judges conditional on their alignment and government vulnerability. Empirically, we analyze all appointments to Spain’s Supreme Court between 1975 and 2023 and all candidacies to internal elections in the regional High Courts (Tribunales Superiores de Justicia) between 1989 and 2023. We find that early political exposure significantly increases a judge’s probability of promotion to the Supreme Court, and that this effect is stronger under narrow parliamentary majorities and conservative judicial councils. These results suggest that judicial careers are shaped not only by internal meritocratic criteria but also by strategic alignment with political actors’ goals. Our findings contribute to debates on democratic backsliding, de facto judicial independence, and informal channels of institutional capture. By showing how political dynamics affect judicial promotion well before formal nomination processes take place, the paper offers a new perspective on how judicial autonomy is subtly undermined in civil law systems.