Judicial Ideology as a Check on Executive Power

The ideological outlook of federal judges has long been a focal point for criticism of the judiciary, but it has taken on new urgency with the escalating political rhetoric and polarization in Washington. President Trump’s recent reference to a district court judge as an “Obama Judge,” after the judge ruled against the Administration in an immigration case, exemplifies the increasingly partisan view of federal judges. In an unusually high-profile response, Chief Justice Roberts defended the judiciary by asserting categorically that “[w]e do not have Obama judges or Trump judges, Bush judges or Clinton judges . . . . What we have is an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them.”

Justice Roberts’s statement may appear defensive or naive, particularly in an era of hyper-politicized judicial confirmations. However, setting aside the Supreme Court, the evidence that exists on the influence of judicial ideology is mixed at best, as most empirical studies find that a judge’s politics have only a modest impact on case outcomes. Existing studies also overlook how changes in executive branch policies affect judicial review and thus confound the influence of judicial ideology with presidential politics. In this study, we find that the influence of judicial ideology on case outcomes is mediated by the partisanship of the executive branch. Thus, while public debates about the federal judiciary focus on whether judges are political, the underlying driver is often politically driven conflicts between executive branch policies and governing statutes.

Overall, judicial ideology affected case outcomes in less than five percent of the appellate cases we analyzed over roughly a fifteen-year period spanning the George W. Bush and Barack Obama Administrations. The influence of ideology on case outcomes was lowest during the Obama Administration, when presidential politics aligned strongly with the environmental laws we studied. Moreover, when it was a factor during the Bush Administration, judicial ideology had a moderating effect on executive branch policies through judicial opinions that guided policies towards centrist positions more in line with statutory mandates, which may or may not align with the current political views of the executive branch or Congress.