Measuring Judicial Legitimacy: Public Support for the Mexican Supreme Court, 1998–2024

Introduction Survey indicators of judicial support, trust, approval, and performance ratings are often treated as interchangeable. This study tests whether this assumption holds for Mexico's Supreme Court, using two decades of surveys to assess whether wording yields different pictures of public support, with implications for judicial‐legitimacy research. Methods The analysis draws on 43 surveys, 1998–2024 (N = 46,560). Pooled logistic regression with survey fixed effects, plus multilevel and survey‐specific models, assesses correlates of Court support across four wordings—autonomy, approval, rating, trust—and tests whether presidential co‐partisanship shapes support and how wording‐adjusted latent indices vary over time. Results Presidential approval and satisfaction with democracy are positive and significant across wordings, though magnitude differs by type: approval items are most responsive, ratings are intermediate, and trust is most stable. Co‐partisanship with the president independently predicts higher support, though spillover does not vary by alignment. Demographics play a limited role, and latent indices show no decline in support before the 2024 reform. Conclusion Trust, approval, and performance ratings are not interchangeable: they differ in baseline levels and political sensitivity, with implications for judicial‐legitimacy trends. Court support appears shaped mainly by political attitudes rather than demographics, with no broad erosion ahead of the 2024 reform.