erhaps no concept in the social sciences has received as much renewed attention as the nearly age-old concept "legitimacy." 1 Scholars of many different intellectual persuasions are being attracted to the concept, even including conventional rational choice researchers (e.g., Vanberg 2001). , and interest in legitimacy extends across several disciplines within the social sciences (e.g., Jost and Major 2001; Tyler 2006). While legitimacy is a concept that can be associated with many different objects (e.g., nations, governments as a whole, cultural values 2), our focus here is on institutional legitimacy, and in particular on the institutional legitimacy of the U.S. Supreme Court. Scholarship on various aspects of the Court's legitimacy has exploded in the past decade or so, with many new studies contributing to the wellestablished conventional wisdom-even if many new studies also challenge established dogma, raising a host of significant empirical and theoretical issues. Legitimacy is a concept particularly relevant to courts, especially non-elected courts like the U.S. Supreme Court. In a democratic polity, accountability and the consent of the governed form the most common source of institutional legitimacy. For many political institutions, legitimacy arises from the social contract.