This article investigates the relationship between the political preferences of E.U. Member States and the behavior of judges at the European Court of Justice (ECJ) by analyzing their citation behavior. It shows that judges at the ECJ are more likely to cite judgments authored by judges appointed by Member State governments with similar preferences regarding European integration. Analogous with the context of U.S. courts, nonrandom opinion assignment potentially threatens the validity of these results. To overcome this problem, I exploit the unique institutional setting at the ECJ to develop an improved identification strategy that builds on comparing the citations in two documents produced in the same case (i.e., the judgment and the opinion of the Advocate General). The findings in this article provide evidence for the hypothesis that the political preferences of Member State governments are reflected in the behavior of the members of the ECJ.