Explaining the diffusion of judicial reform policies among the American States is an elusive task. It begins with Max Weber's sociology of law from which his concept of rationalization is adopted as a schema of policy development. According to Weber, the 'rationalization' of legal institutions would accompany the advancement of capitalism in modernizing nations. Thus, it is expected that specific judicial reform policies expressly aimed at rationalizing the structure and process of State court systems be closely associated with each other and with commonly accepted indicators of economic development among the States. Court reforms are related to broader policy innovations among the States, drawing on earlier 'diffusion of innovations' research. The data indicate a strong connection between judicial reform and more general patterns of innovation diffusion among the States, but provide only modest support for Weber's assertions about the rationalization of legal systems under advancing capitalism. Three of the selected reforms cluster together and are largely explainable by indicators of economic development. Two other reforms do not fit this pattern, and their 'behavior' requires additional discussion and research. Thus, the diffusion of judicial reform policy is partly accounted for by factors found in explanations of general policy innovations across States, but other, as yet unidentified, factors apparently influence certain aspects of judicial reform. 4 tables and 62 references. (Author abstract modified)