In Strength in Numbers, Gunnar Trumbull advances a powerful critique and alternative to the dominant understanding of interest-group politics developed by Mancur Olson. -- Jonah Levy, University of California, Berkeley This book makes a bold and startling claim: diffuse interests, rather than concentrated interests, dominate the making of public policy in the advanced democracies. -- Pepper D. Culpepper, European University Institute Trumbull attacks head on the Olson tradition of diffuse versus concentrated interests, which suggests that the concentrated will always defeat the diffuse. He argues that the diffuse often wins-at least far more often than the standard Chicago collective action theory suggests. -- Peter Gourevitch, University of California, San Diego

Many consumers feel powerless in the face of big industry’s interests. And the dominant view of economic regulators (influenced by Mancur Olson’s book The Logic of Collective Action, published in 1965) agrees with them. According to this view, diffuse interests like those of consumers are too difficult to organize and too weak to influence public policy, which is determined by the concentrated interests of industrial-strength players. Gunnar Trumbull makes the case that this view represents a misreading of both the historical record and the core logic of interest representation. Weak interests, he reveals, quite often emerge the victors in policy battles.

Based on a cross-national set of empirical case studies focused on the consumer, retail, credit, pharmaceutical, and agricultural sectors, Strength in Numbers develops an alternative model of interest representation. The central challenge in influencing public policy, Trumbull argues, is not organization but legitimation. How do diffuse consumer groups convince legislators that their aims are more legitimate than industry’s? By forging unlikely alliances among the main actors in the process: activists, industry, and regulators. Trumbull explains how these “legitimacy coalitions” form around narratives that tie their agenda to a broader public interest, such as expanded access to goods or protection against harm. Successful legitimizing tactics explain why industry has been less powerful than is commonly thought in shaping agricultural policy in Europe and pharmaceutical policy in the United States. In both instances, weak interests carried the day.