Judges Judging Judges: Partisanship and Politics in the Federal Circuit Courts of Appeals

We examine how politicization and polarization influence judicial review within U.S. Federal appellate courts. Analyzing over 400,000 cases from 1985 to 2020, we find that judges' political alignment or misalignment with trial judges increasingly affect their decisions, particularly in the last two decades. This trend is significant in precedential cases: panels of Democratic judges are 6.9 percentage points more likely to reverse Republican trial judges compared to Democratic ones, whereas Republican panels are 3.6 percentage points less likely to reverse fellow Republican judges. This effect persists across ideological and non-ideological cases and even among judges appointed before 2000.