Interest group pluralism presumes that public policy outcomes are determined principally through a contest for influence among organized pressure groups. Most interest groups, however, do not represent themselves in this process. Rather, they rely on professional lobbyists for representation, information, and advice. These lobbyists are agents with their own interests, and these interests may not align perfectly with those of their clients. This essay outlines this principal-agent problem and sketches its possible implications for policy outcomes. In particular, we hypothesize that the lobbyist-client agency problem may bias policy in favor of small homogeneous groups, may exacerbate status quo bias and lead to excessive attention to symbolic issues, may promote expansive delegations to administrative agencies, and may impede systematic reforms to the policy-making process
