I am excited to share the preprint summarizing the results of research conducted with my excellent colleague Andreu Rodilla Lazaro (University of Barcelona and Barcelona Supercomputing Center).
While judicial polarization is well-documented in the U.S., our study provides systematic evidence that polarization dynamics are also shaping constitutional courts in parliamentary democracies. Using a dataset of 100,000+ votes across 20,000+ cases (1980-2023), we reveal how Spanish Constitutional Tribunal judges are increasingly sorting into progressive and conservative camps, making dissent more ideologically predictable and extreme over time.
Key Findings:
1) The frequency of dissents has increased, mirroring Spain’s broader political polarization.
2) Judicial appointments, as revealed by latent preference modelling, are becoming more ideologically distinct, reinforcing partisan divisions.
3) The ideological gap between judges, measured by the party manifestos of their appointing parties, is now a strong predictor of disagreement in rulings.
Our research challenges the view that constitutional courts are insulated from polarization. Instead, we show that political forces are shaping judicial behaviour, with implications for judicial independence and democratic governance.
Download Preprint from SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=5124478
Download Preprint from ResearchGate: https://www.researchgate.net/publication/388721113_Ideological_Polarization_on_Constitutional_Courts_Evidence_from_Spain
We welcome feedback and discussion!