We examine scholarship on the role and influence of advocacy organizations in the U.S. political process. We identify common theoretical questions in the disconnected literatures on social movements, interest groups, and nonprofits, and we propose a unifying conceptual framework for examining advocacy organizations. Focusing on the post-1960s growth in advocacy organizations, we examine major organizational characteristics including organizational structures, membership and participation, resources, and interorganizational networks and coalitions. Our analysis of organizational influence focuses on five dimensions of the policy process: (a) agenda setting, (b) access to decision-making arenas, (c) achieving favorable policies, (d) monitoring and shaping implementation, and (e) shifting the long-term priorities and resources of political institutions. Finally, we identify recurrent theoretical and methodological problems, including the compartmentalization of research within disciplines, an overreliance on studies of large national organizations, a disproportionate focus on recruitment and selective incentives, and limited research on the influence of advocacy organizations. We conclude by highlighting productive pathways for future scholarship.
