Does the US administration exercise more informal influence over the World Bank when it has less control over US bilateral aid because of opposition from Congress? Replicating four studies of the World Bank, we show that years with a divided US government account for earlier findings of informal influence. This link between donor domestic politics and the exercise of influence in multilateral settings is important for understanding informality in international organizations and provides an alternate explanation to persistent questions about the role of international organizations in the international political economy.