A large body of empirical evidence demonstrates that judicial review of agency action is highly politicized in the sense that Republican appointees are significantly more likely to invalidate liberal agency decisions than conservative ones, while Democratic appointees are significantly more likely to invalidate conservative agency decisions than liberal ones. These results hold for both (a) judicial review of agency interpretations of law and (b) judicial review of agency decisions for arbitrariness on questions of policy and fact. On the federal courts of appeals, the most highly politicized voting patterns are found on unified panels, that is, on panels consisting solely of either Democratic or Republican appointees. On the Supreme Cour...