From the late 1970s on, penal populism, or the tendency for the public to support harsh criminal justice policies, has been recognized as a driving force of socially and economically costly punitive trends in the Western world. This support has traditionally been attributed to political leanings and related ideological systems. A competing view is that policy preferences reflect deep-seated individualizing and binding moral systems. However, each view has difficulty refuting the other in empirical and theoretical terms. Using a structural equation modeling approach, this study applies 2 competing theoretical models to investigate the ideological and moral underpinnings of public support for harsh criminal justice policy. Results suggest both ideological and moral components to public punitiveness. Though right-wing authoritarianism was most strongly associated with supporting harsh criminal justice policies, we find some indication of the underlying importance of moral concerns. We argue that persistent public calls for harsh criminal justice policy could be abated by appealing to deeply ingrained and universal moral concerns about fairness.