Abstract: Using a novel dataset of about 640,000 circuit court decisions from 1985 to 2020, I show that panel political composition is associated with case outcomes in a vastly broader array of federal circuit court cases—representing together about 90% of all cases—than prior work has appreciated. In cases between parties that could be perceived to have unequal power, Democratic-nominated judges tend to have a “Pro-Weak” tendency to side with the seemingly weaker party. In cases without perceived power inequality, Democratic-nominated judges tend to have a “Less-Deference” tendency to be more willing to reverse lower court decision.