Organized interests have long driven power relations in Japan, yet they are often overlooked in political histories that tell of bureaucrats prevailing over politicians, the Japanese state suppressing the people, or social movements protesting against the state. Missing in many of these accounts is the associational middle that informed political practice. My dissertation takes into account relevant aspects of agricultural cooperatives, peak business federations, and other professional and trade associations from 1890 to 1996, while focusing in archival detail on the leading lawyer and newspaper associations. By treating "politics by association" in historical terms informed by social science concepts, I propose to answer two questions: What explains the success of Japan's organized interests in shaping political practice in spite of both hostile or indifferent governments and regular appeals by bureaucrats and politicians to "transcend" factional interests? And, what does the twentieth-century Japanese experience demonstrate about the evolving construction and mediation of links between government and the public, in comparison to other developed nations? These two questions are addressed in a longitudinal study that focuses on the political processes in Japan while drawing on analysis of the U.S. and nations in Europe. By juxtaposing present theorization about political action in public and private spheres with an analysis of interactions between Japanese associations, national and local governments, and broader publics over the course of the twentieth-century, I hope to contribute to the ongoing re-conceptualization of organized interests as actors in modern politics.