Focusing on the psychological underpinnings of partisanship, this study asks whether there is a difference in the personality profile for self-described Democrats and Republicans. Using a survey of young voters (N = 610), psychological measures such as the Big Five personality dimensions and locus of control were measured in conjunction with standard political interest variables such as political cynicism and political information efficacy. The results indicate supporters for the two major parties are wired differently, in line with previous findings about ideology. Democrats were driven by an external locus of control and Republicans by an internal locus. This research finds self-identified Independents as truly being somewhere in between.